EVERYDAY SCIENCE
(Everything you need)
1. LPG: Liquefied Petroleum Gas
2. TNT: Tri Nitro Toluen
3. RNA: Ribonucleic Acid
4. CNG: Compressed Natural Gas
5. ATP: Adenosine Tri Phosphate
6. RBC: Red Blood Cells/Corpuscles
7. ECG: Electro Cardio Gram
8. PVC: Poly vinyl
Chloride
9. RAM: Random Access Memory
10. CFC: Chloro Fluoro Carbon
11. LASER: Light Amplification by Stimulated emission of
Radiation
12. RADAR: Radio Detection And Ranging
13. AIDS: Acquired Immune Deficiency Syndrome
14. ROM: Read Only Memory
15. LAN: Local Area Network
16. WWW: World Wide Web
17. DNA: Deoxyribonucleic Acid
18. SONAR: Sound Navigation And Ranging
19. SARS: Severe Acute Respiratory Syndrome
20. NTP: Network Time Protocol/ Normal
Temperature and Pressure
21. RQ: Respiratory Quotient
22. NPN: Negative Positive Negative
23. PNP: Purine Nucleoside Phosphorylase
24. WAN: Wide Area Network
25. CPU: Central Processing Unit
26. BCG: Bacillus Calmette Guerin
27. STP: Standard Temperature And Pressure/Shielded Twisted
Pair/Sodium
Tripolyphosphate/Spanning Tree Protocol
28. ATP: Adenosine Triphosphate
29. KWh: Kilo Watt Hour
30. BTU: British thermal Unit
31. LDL: Low Density Lipoprotein
32. MAF: Million Acre
Feet
33. HDL: Hardware Description Language
34. MCV: Mean Corpuscular Volume
35. UHF: Ultra High Frequency
36. LED: Light emitting Diode
37. LCD: Liquid Crystal Display
38. BASIC: Beginner‘s All-Purpose Symbolic Instruction Code
39. MASER: Microwave Amplification by Stimulated Emission of
Radiation
40. ETT: Educational Telecommunications and Technology/
European Transaction on
Telecommunication
41. HST: High Speed Technology/ High Speed Train (in UK )/Hubble
Space Telescope
42. DBS: Data Base Server/ Direct Broadcast Satellite
43. CRO: Cathode Ray Oscilloscope
44. BOT: Build, Operate and Transfer/Botulinum Toxin
45. AMU: Atomic Mass Unit
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46. EMF: Electro Motive force
47. ADH: Anti-diuretic Hormone
48. GeV: Giga Electro Volt
49. CRT: Cathode Ray Tube
50. CNS: Central Nervous System
51. PTFE: Poly Tetra Fluoro Ethylene
52. GUT: Grand Unified Theory
53. LONAR: Long
Range
54. MeV: Mega Electron Volt/ Million Electron Volt/
Multi-experiment Viewer
55. AWACS: Airborne Warning and Control System 56. CCTV: Closed-Circuit Television
1. ABM: Anti-Ballistic Missile
2. AC: Alternating Current/Air Conditioning
3. AEC: Atomic Energy Commission
4. Alt: Altitude
5. am: Ante Maridiem (Before Noon/Midday)
6. Amp: Ampere
7. APTEC: All Pakistan Technology Engineers
Council
8. ATM: Automated Teller Machine (Banking)
9. AW: Atomic Weight/
Asia Watch
10. BIOS: Basic Input Output System
11. BDS: Bachelor Of Dental Surgery/ Bomb Disposal Squad
12. BP: Blood Pressure/ Boiling Point/ Blue Print 13. C/A: Current Account
14. CAA: Civil Aviation Authority
15. CABB: Centre Of Agricultural Biochemistry And
Biotechnology 16. CAD: Computer-Aided
Design
17. Cal :
Calorie
18. CD: Compact Disc/ Civil Defence/ Community Development
19. CD-ROM: Compact Disc Read-Only Memory
20. CECP: Cotton Export Corporation Of Pakistan
21. CHASNUPP: Chashma Nuclear Power Plant
22. CMCC: China Mobile Communications Corporation
23. COM: Computer Aided Manufacturing
24. COMSAT: Communications Satellite Corporation
25. COMSTECH: Council Of Scientific And Technology
Cooperation Of Islamic Conference
26. CSIRO: Commonwealth Scientific And Industrial Research
Organisation
27. CTBT: Comprehensive Test Ban Treaty
28. CT-Scan: Computerised Axial Tomography Scanning
29. DVD: Dynamic Versatile Disc
30. ECAT: Engineering Colleges Admission Test
31. EDB: Engineering Development Board
32. EEG: Electroencephalogram
33. ENERCON: Energy Conservation Centre
34. EPA: Energy Protection Agency
35. EPD: Energy Protection Department
36. ESA: European Space Agency
37. ESRO: European Space Research Organisation
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38. FAT: File Allocation Table
39. FCPS: Fellow Of The Royal College
40. FM: Frequency Modulation
41. FMCT: Fissile Material Cut-Off Treaty
42. FRCS: Fellow Of The Royal College
43. GHz. Gigahertz
44. GMT: Greenwich
Mean Tim
45. HIV: Human Immune Deficiency Virus
46. HTML: Hypertext Mark-Up Language
47. HTTP: Hypertext Transfer Protocol
48. IAEA: International Atomic Energy Agency (UN)
49. IBM: International Business Machine
50. IC: Integrated Circuit/ Intelligence Corps
51. ICBM: Inter-Continental Ballistic Missile
52. ICU: Intensive Care Unit
53. IEA: International Energy Agency
54. INSTRAW: International Research And Training Institute
For The Advancement Of
Women
55. INTELSAC: International Telecommunications Satellite
Consortium
56. Intelsat: International Telecommunications Satellite
Organisation
57. IRBM: Intermediate
Range
58. ISP: Internet Service Provider
59. IT: Information Technology
60. ITB: Information Technology Board
61. JAXA: Japan Aerospace Exploration Agency
62. KANUPP: Karachi
Nuclear Power Plant
63. KAPCO: Kot Adu Power Company
64. kHz:
Kilohertz
65. KV: Kilo
Volt
66. kW: Kilowatt
67. MCAT: Medical Colleges Admission Test
68. MDS: Master In Dental Surgery
69. MNP: Mobile Number
Probability
70. MRBM: Medium
Range
71. MRCP: Member Of Royal College
72. MRCS: Member Of Royal College
73. MRI: Magnetic Resonance Imaging
74. MS: Medical Superintendent
75. MSN: Microsoft Network
76. MW: Megawatt
77. NADRA: National Database And Registration Authority
78. NEPRA: National Electric Power Regulatory Authority
79. NM: Nautical Mile
80. NMD: National Missile Defence
81. NPT: Non-Nuclear Proliferation Treaty
82. NRA: Nuclear Regulatory Authority
83. OGRA: Oil And Gas Regulatory Authority
84. NWD: Nation Wide Dialling
85. OGDC: Oil And Gas Development Corporation
86. pm: Post Meridiem
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87. PEMRA: Pakistan
Electronic Media Regulatory Authority
88. PTA: Pakistan
Telecommunication Authority
89. RADAR: Radio Detection and Ranging
90. SALT: Strategic Arms Limitation Talks
91. SLV: Satellite Launch Vehicle
92. SMS: Short Message Service
93. SNGPL: Sui Northern Gas Pipelines Limited
94. SONAR: Sound Navigation And Ranging
95. SSGPL: Sui Southern Gas Pipeline Limited
96. STD: Subscriber‘s Trunk Dialling
97. STM: Subscriber Identification
98. SUPARCO: Space And Upper Atmosphere Research Committee (Pakistan )
99. TB: Tubercle Bacillus/ Tuberculosis
100. UHF: Ultra High Frequency
101. UNAEC: United Nations Atomic Energy Commission
102. UNESCO: United Nations Education, Scientific And
Cultural Organisation
103. VCD: Video Compact Disc
104. VHF: Very High Frequency
105. WAN: Wide Area Network
106. WAP: Wireless Application Protocol
107. WAPDA: Water And Power Development Authority
108. WHO: World Health Organisation
109. WMD: Weapons Of Mass Destruction
110. WWF: World Wildlife Fund
111. ZPG: Zero Population Growth
2. Units
1. Force: Newton /
Dyne
2. Temperature: Kelvin/ Celsius/ Degree
3. Current: Ampere
4. Heat: Joule/ Calorie/ BTU
5. Pressure: Pascal/Torr
6. Radioactivity: Becquerel/Curie/Rutherford
7. Atomic energy: Rydberg/Joule
8. Voltage: Volt
9. Electric Potential Difference: Volt
10. Electric Charge: Coulomb
11. Power: Watt
12. Resistance: Ohm
13. Conductivity: Mho
14. Energy: Joule/ Erg
15. Distance Between Stars And Planets: Light Year
16. Wavelength: Angstrom
17. Volume: Acre-Foot/Litre
18. Frequency: Hertz
19. Rate of flow of water: Cusec
20. Length: Meter/Fermi/Parsec
21. Optical Power Of A Lens or A Curved Mirror: Dioptre
22. Plane Angle: Radian
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23. Luminous Intensity: Candela
24. Amount of Substance: Mole
25. Rate Of Decay Of Radioactive Material: Rutherford
26. Sedimentation Rate: SVEDBERG Unit
27. Induction: Henry
28. Magnetic flux: Maxwell/ Weber
29. Magnetic Flux Density/Magnetic Inductivity: Telsa/Gauss
30. Electric Conductance: Siemens
31. Angle: Degree
32. Solid Angle: Steradian
33. Torque: Foot-Pound
34. Mass: Slug
35. Volume of Water Reservoirs: Acre-foot
36. Mechanical work/Energy: Erg
37. Magneto Motive Force: Gilbert
38. Newton :
Force
39. Dyne: Force
40. Kelvin: Temperature
41. Celsius: Temperature
42. Degree: Temperature
43. Ampere: Current
44. Joule: Heat/Atomic Energy/Energy
45. Calorie: Heat
46. BTU: Heat
47. Pascal: Pressure
48. Torr: Pressure
49. Becquerel: Radioactivity
50. Curie: Radioactivity
51. Rutherford : Rate Of
Decay Of Radioactive Material/Radioactivity
52. Rydberg: Atomic Energy
53. Volt: Voltage/Electron Potential Difference Coulomb: Electric Charge
55. Watt: Power
56. Ohm: Resistance
57. Mho: Conductivity
58. Erg: Energy
59. Light Year: Distance Between Star
60. Angstrom: Wavelength
61. Litre: Volume
62. Acre Foot: Volume
63. Hertz: Frequency
64. Cusec: Rate Of Flow Of Water
65. Meter: Length
66. Fermi: Length
67. Parsec: Length
68. Dioptre: Optical Power Of Lens
69. Radian: Plane Angle
70. Candela: Luminous Intensity
71. SVEDBERG: Sedimentation Rate
72. Henry: inductance
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73. Maxwell: Magnetic Flux
74. Weber: Magnetic Flux
75. Tesla: Magnetic Flux Density/Magnetic Inductivity
76. Gauss: Magnetic Flux Density/Magnetic Inductivity
77. Siemens: Electric Conductance
78. Degree: Angle
79. Steradian: Solid Angle
80. Foot Pound: torque
81. Slug: Mass
3. Discoveries/Inventions-Scientists Past Papers
1. Structure Of DNA: Watson & Crick
2. Rabies Vaccination: Louis Pasteur
3. Penicillin: Alexander Fleming
4. Genetic Laws of Heredity: Mendel
5. Vaccination Against Small Pox: Edward Jenner
6. Solar System: Copernicus
7. Current Electricity: Volta
8. Telephone: Graham Bell
9. Gramophone: Thomas Edison
10. Atomic Number: Mosley
11. Mercury Thermometer: Fahrenheit
12. Dynamite: Alfred Noble
13. Cell: Robert Hooke
14. Television: John Baird
15. X-rays: Roentgen
16. Circulation Of Blood: William Harvey
17. Bicycle: Macmillan
18. Wireless Telegraphy: Signor Marconi
19. Microorganisms: Antoni Van Leeuwenhoek
20. Laser: Dr. C. Gilbert
21. Periodic Table: Mendeleev
22. Radium: Madam Marie Curie
23. Mass/Energy Conversion Equation: Einstein
24. Cement: Joseph Aspdin
25. Simple Microscope: Hans Janssen and Zacharias Janssen
26. Sulphuric, Nitric and Hydrochloric Acid: Jabir Bin Hayan
27. Jet Engine: Frank Whittle
28. Electricity: Thomas Edison
29. Computer: Charles Babbage
30. Lightening Conductor: Benjamin Franklin
31. Semiconductor: Bardeen and Brattain
32. Uncertainty Principle: Heisenberg
33. Cyclotron: Ernest Lawrence
34. Electro Magnetic Engine: James Maxwell
35. Internal Combustion Engine: Nikolas August Otto
36. Earth As A Huge Magnet: William Gilbert
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37. First Person To Orbit Earth: Yuri Gagarin
38. Water: Henry Cavendish
39. Gravitation: Newton
40. Magnet: Dr. Gilbert
41. E.M Induction: Faraday
42. Energy Quanta: Max Planck
43. Vitamin. C Therapy: Linus Pauling
44. First Clone Of A Sheep: Ian Wilmit
45. Streptomycin: S.A.Waksman
46. Helical Structure Of Protein: Linus Pauling
47. Polio Vaccine: Jonas Salk
48. Nylon: Wallace. H Carothers
49. Radioactivity: Becquerel
50. Safety Match: John Walker
51. Gun Powder: Roger Bacon
52. Jupiter: Galileo
53. Neutron: James Chadwick
54. Earth‘s Radius: Eratosthenes
55. Oxygen: Joseph Priestley
56. Noble Gases: Cavendish
57. Synthesis Of Gene In Laboratory: Hargobind Khorana
58. Earth Revolves Round The Sun: Copernicus
59. Binomial Nomenclature: Carl Von Linnaeus
60. North America :
Christopher Columbus
61. Green
Land
62. Transistor: William Bradford Shockley
63. Typewriter: Sholes
64. Bacteriology: Pasteur
65. Laser: Theodore
Maiman
66. Father Of Botany: Theophrastus
67. Father Of Zoology: Aristotle
68. Father Of Taxonomy: Carolus Linnaeus
69. Father Of Genetics: Gregor Mendel
70. Cell Theory: Scheilden And Schwann
71. Cholera Bacillus: Robert Koch
72. Theory Of Relativity And Photoelectric Effect:
Einstein
73. Insulin: Dr. F.G Banting
74. Nucleus: Robert Brown
75. Chromosome: Waldeyer
76. Ultra Violet Rays: Johann Wilhelm Ritter
77. Law Of Attraction And Repulsion Between Electric
Charges: Coulomb
78. Battery : Alessandro
Volta
79. Electromagnetic theory: James Clerk Maxwell
80. First Person To Televise Pictures Of Moving Objects:
John Logie Baird
81. Antiseptic Medicine: Joseph Lister
82. Cotton Gin: Eli Whitney
83. Big Bang Theory: Georges Lemaitre
84. Electron: J.J Thomson
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85. Aeroplane: Wilbur and Orville Wright
86. Steam Railway Locomotive: Richard Trevithick
87. Radio: Marconi
88. Household Vacuum Cleaner: Herbert Cecil Booth
89. Bakelite: Baekeland
90. Windscreen Wipers: Marry Anderson
91. Ballpoint pen: Laszlo And Georg Biro
92. Helicopter: Igor Sikorsky
93. DDT: Paul Muller
94. Blood Banking: Charles Drew
95. AK-47: Mikhail Kalashnikov
96. Integrated Circuit: Robert Noyce
97. Cellular Phone: Dr. Martin Cooper
98. Vitamins: Funk
99. Uranus: Herschel
100. Calculating Machine: Blaise Pascal
101. Tuberculosis: Robert Koch
102. Logarithm Table: John Napier
103. Malaria Parasite: Ronald Ross
104. Zero: Al Khwarizmi
105. Velocity Of Light: Roomer
4. Measuring Tools
1. Pressure: Barometer
2. Voltage: Voltmeter
3. Purity Of Milk: Lactometer
4. Temperature: Thermometer
5. Velocity Of Wind: Anemometer
6. Earthquake: Richter Scale
7. Degree Of Humidity: Hygrometer
8. Blood Pressure: Sphygmomanometer
9. Radioactivity: Geiger Counter
10. High Temperature: Pyrometer
11. Rainfall: Rain Guage
12. Earthquake Recording: Seismograph
13. Electric current: Ammeter
14. Altitude: Altimeter
15. Velocity And Direction Of Wind: Anemometer
16. Sensitivity Of Skin: Algeismeter
17.AtmosphericPressure: Aneriodograph/Barometer
18. Improvement Of Hearing Power: Audiometer
19. Quantity Of Heat: Calorimeter
20. Intensities Of Colours: Colorimeter
21. Longitude Of Vessel
Over Sea
22. Detection Of Electric Charge: Electroscope
23. Voltage Difference: Electrometer
24. Depth Of The Ocean: Fathometer
25. Small Electric Current: Galvanometer
26. Relative Density of Liquids: Hydrometer
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27. Change In Atmospheric Humidity: Hygroscope
28. Detection And Measurement Of Light: Photoelectric
Cell
29. Salinity Of Water: Salinometer
30. Spectrum Analysis: Spectroscope
31. Hearing Of Heartbeat And Lung Sound: Stethoscope
32. Maintenance Of A Constant Temperature: Thermostat
33. Amplification Of Current: Transistor
34. Measurement OF Potential Difference Between Two Points:
Voltammeter
35. Flow Of Air: Aerometer
36. Radiant Energy: Radiometer
37. Conversion Of Rays Into Mechanical energy: Radiograph
38. Measurement Of Intensity Of Light: Lucimeter
1. The energy of food is measured in Calories
2. The microscope is used to study Small and near objects
3. The S.I unit of temperature is Kelvin
4. The telescope is used for viewing Distant Objects
5. Decibel is a unit of Sound
6. The instrument used to measure Electric Current is
Ammeter
7. The apparatus used in submarines to give a clear view of
the object, on the surface of the ocean or
ground is known as Periscope
8. Richter Scale is used for measuring Intensity Of
Earthquake
9. Fathometer is used to measure Ocean Depth
10. Hygrometer is used to measure Relative Humidity
11. Venturi Tube is used for Measuring Flow Of A Fluid
12. Coronagraph is used for Observing and often
photographing the sun‘s corona
13. Microphone is used to convert sound waves into electric
energy
14. Velocity of wind is measured by Anemometer
15. Altimeter is used to measure the approximate height
above the ground
16. Light year is related to Distance
17. Pressure of gases is measured by Barometer
18. Altitude of the Sun is measured by Sextant
19. There are 981 Dynes in one gram weight
20. When listening to heart beat with stethoscope, one hears
closing of valves
21. The unit of Current is Ampere
22. The unit of energy in MKS system is Joule
23. The intensity of an earthquake is measured by
Seismograph
24. Centigrade and Fahrenheit scales give the same reading
at -40 Degree
25. The instrument, which is used to measure temperature by
radiation, is called Pyrometer
26. Centrifuge is used to separate mixtures of chemicals
27. Radio Telescope is used to receive radio waves from
objects in space
28. Audiometer is used to measure intensity of sound
29. A chronometer is used to measure time
30. Electroscope detects the presence of electric current
31. Stroboscope is used to view rapidly moving objects
32. Taceometer is used to measure distance, elevations and
bearings during survey
33. Retinoscope is an instrument used to determine
Refractive power of lens
34. The final image produced by a simple microscope is
Virtual and Erect
35. Photodiode is used for the detection of Light
36. A Polaroid is a device used for analysing polarized
light
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37. The spectrum of luminous bodies is studied by
Spectrometer
38. Transformer is used for conversion of low voltage into
high voltage and vice-versa
39. Ophthalmoscope is used to observe Retina
40. Sonar works on the principle of Absorption of sound
5. Everyday Science MCQS Material
1. When the resultant of all the forces acting on a body is
zero the body is said to be in a state
of Equilibrium.
2. Gamma Rays are similar to X-Rays.
3. The Separation of ordinary light into its constituent
colours is known as Dispersion.
4. If a body weighs 600 kg on the surface of the earth then
the weight of the same body on the surface
of moon will be 1/6th i.e. 100kg.
5. When a bullet penetrates into a target, the kinetic
energy of a bullet is converted into Mechanical
Energy.
6. The process of digestion begins in Mouth.
7. Sometimes when white blood corpuscles greatly increase in
number, they cause a disease
called Leukaemia.
8. The principle of wireless telegraphy was discovered by
Signor Marconi.
9. The planet nearest to sun is Mercury.
10. Pressure cooker works on the principle that the boiling
point of a liquid increases with the
increase of pressure.
11. Copper is the best conductor of electricity.
12. Blood cells are manufactured by bone marrow of the body.
13. The smallest organism which causes disease is virus and
even smaller is called viroids.
14. Neutron, electron and Proton have neutral, negative and
positive charges respectively.
15. Of all the flying machines that man has made only
Rockets are suitable for space flight.
16. Transistors do not need a warm up period because they
have no Filaments.
17. If an object gives off its own light, it is said to be
Luminous.
18. An electric heater would be most likely to produce I.R
Radiations.
19. The Kelvin scale of temperature is called the absolute
scale.
20. The type of radiation that is unaffected by magnetic
field is called Gamma Rays.
21. If we know the mass of an object and the force applied
on it, it is possible to
calculate acceleration of the object.
22. Active transport in animals and plants required
metabolic energy and Concentration Gradient to
carry the substances across cell membrane electrical
gradient.
23. Diseases that spread through air are called Air Borne
diseases.
24. When iron is less in body, the quantity of Haemoglobin
in cell decreases.
25. Arteries become hard due to deposition of Fats and
Cholesterol in them.
26. The science of study of old age is called Gerontology.
27. The instrument used for measuring the velocity is called
Anemometer.
28. The science which deals with the bird is called
Ornithology.
29. The function of the thermostat in a refrigerator is to
maintain temperature.
30. Blotting paper absorbs ink because the action of
capillary.
31. Mirage is an example of Reflection of Light.
32. The age of a tree can be determined by counting Rings of
stem.
33. In a normal resting man, the rate of heart beat is 72
per minute.
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34. In Pakistan
copper is found in Saindak.
35. American space shuttle Mercury Atlas-6 is the first
winged space ship to orbit and return to
airport landing.
36. Myopia is a defect of vision which does not permit to
see clearly the distant objects.
37. The brightest planet is Venus.
38. Urea s not a phosphorous fertilizer.
39. Ibn Baitar was a renowned Muslim Botanist.
40. Cellulose is natural polymer.
41. Vitamin A & D are not water soluble.
42. Amoeba is a unicellular animal.
43. Solar eclipse occurs in full moon.
44. Leprosy is a disorder of the Nervous System.
45. Chlorofluorocarbons (CFCs) cause decomposition of ozone.
46. Quartz is chemically a Silicate or Silicon dioxide.
47. Chicken egg is composed of One Cell.
48. Visible light energy has the wave length range of
400-700 nm.
49. The particle with positive charge but having mass equal
to that of electron is called Positron.
50. Gas in children‘s play-balloons going upward is
hydrogen.
51. Standard pressure is 760 mm-Hg.
52. Iron corrodes due to the formation of Iron Oxide.
53. Starch is a polymer of Glucose.
54. Adrenalin is secreted by the Adrenal Gland.
55. Mars planet is nearest to the earth.
56. The process of conversion of a material from solid state
directly to gaseous state is
called Sublimation.
57. Bacteria are parasite.
58. Ruby is an oxide of Aluminium.
59. In the Australian continent nights are larger than days
in June.
60. Gypsum is not hydrated calcium carbonate.
61. Uranus is the coldest planet.
62. Chromite ore contains chromium oxide.
63. Mica is a non-conductor of electricity.
64. Sun is not the biggest star in the universe.
65. The capacity to do work is called energy.
66. The energy possessed by body due to its position is
called potential energy.
67. Kitab-al-Manazar is publication by a famous Muslim
Scientist about Optics.
68. Nucleus usually lies in the centre of animal cells.
69. Calcium and phosphorous are the essential elements of
bones.
70. Proteins are formed by combination of amino acids.
71. Rain water dissolves Sulphur dioxide to form Sulphuric Acid.
72. The set of instruction given to a computer is called
command.
73. Chemicals such as penicillin which act on bacteria are
called antibiotics.
74. Comet shoemaker-levy 9 hit the planet Jupiter in July
this year.
75. A branch of medicine studying blood and its disorders is
called Haematology.
76. Cytology is the branch of biology which deals with the
study of structure and function of cells.
77. A biological study of external form and structure of
living organisms or their parts
is Morphology.
78. Am academic and applied discipline which involves the
scientific study of human or animal
mental functions and behaviours is called Psychology.
79. A study of the chemical composition of the earth‘s crust
is called Geology.
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80. In a heat engine heat energy is changed into Mechanical
Energy.
81. Frequency of audible sound is 20-20,000 Hz.
82. Deficiency of vitamin B causes Beriberi.
83. Cheapest source of producing electricity is Water.
84. The smallest unit of measurement of wave-length is
Angstrom.
85. The chemical generally used in refrigerator is Freon.
86. The unit ―TON‖ to specify air conditioners is equivalent
to 12,000 BTU/hour.
87. Unit of electricity ―Kilowatt Hour‖ is the unit of
Power.
88. Period of famous Muslim scientists is 7th to 13th
century A.D.
89. Heat radiation travels at a speed equal to Speed of
light.
90. Cryptograms are non-flowering plants.
91. Reserve food material is usually stored as Starch in
plants and Glycogen in animals.
92. Streptococcus is a gram positive bacterium.
93. Spinach is a good source of vitamin K.
94. Insulin is a hormone secreted by the pancreas.
95. Femur is a bone of the leg. 96. The moon has no atmosphere.
97. Excessive burning of the fossil fuels causes acid rains.
98. Twenty first of June is the longest day of the year in
the northern hemisphere.
99. Electricity is a secondary source of energy.
100. The outer most layer of the earth is called Crust.
101. Newton
is the unit of Force.
102. Radium was discovered by Madam Marie Curie.
103. The memory of the computer is expressed in bytes
104. AIDS is caused by Human Immunodeficiency Virus (HIV).
105. Chemical name of gypsum is Calcium Sulphate.
106. Molten super-hot material present inside a volcano is
called Magma/Lava.
107. Richter scale measures the severity of Earthquake.
108. pH of blood is 7.3-7.4.
109. one of the countries through which equator passes is Kenya .
110. Purest form of iron is Wrought Iron.
111. Hypo is a solution of sodium thiosulphate.
112. Cod liver oil contains Vitamin D.
113. Aorta is a n organ of the Circulatory System.
114. Planet Mars has two moons.
115. Bauxite is an ore of Aluminium.
116. Circular aperture which appears as a dark spot in the
eyes is called pupil.
117. The speed of light is nearly 300, 0000 km/sec.
118. Ideally water can be used as a car fuel after
electrolysis.
119. Our eye is very sensitive to blue light.
120. Al Beruni died in 1048 A.D.
121. Abu ail Sina born in Iraq .
122. Blue colour has shortest wavelength.
123. Light travels fattest in Vacuum.
124. The universe is Expanding.
125. The disease, Haemophilia is caused by the deficiency of
Vitamin K.
126. Protein is a nautral polymer.
127. Astronomers cannot be nominated for the Noble Prize.
128. A sheet of muscles called Diaphragm separates the chest
from the abdomen.
129. In human body, blood clotting factor is produced by the
platelets.
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Human blood is able to carry large amounts of oxygen because
of the Haemoglobin.
130. The living part of a plant cell is composed of a
nucleus and cytoplasm.
131. The pattern for building protein molecule is stored in
the messenger RNA.
132. Anvil and stirrup are names of bones present in the
ear.
133. The front of the eye is covered with a tough
transparent material called Cornea.
134. The young plant inside a grain of wheat is called the
Embryo.
135. Inborn behaviour that involves only one part of the
body is called Reflex Action.
136. The smallest branches of an artery lead into tiny blood
vessels called capillaries.
137. Eustachian tube belongs to ear.
138. Cartilage is a connective tissue.
139. Auricle is present in heart.
140. Tendon is a muscle.
141. Dendrites are the part of Neuron.
142. In an animal cell protein is synthesized in the
Ribosome.
143. Chemically finger nails are made up of protein.
144. Muscle stiffness is symptom caused by the disease
Tetanus.
145. Riboflavin (vitamin B2) is not affected by cooking.
146. Thiamine is vitamin B1.
147. Ascorbic acid is vitamin C.
148. Rickets is caused by the deficiency of vitamin D.
149. The number of chromosomes in the spermatozoon is 23.
150. The fat in our food is digested by the Enzyme Lipase.
151. The most abundant element in the human body is Oxygen.
152. Sound is a form of energy.
153. A fraction of sunlight is refracted as it enters the
earth‘s atmosphere.
154. Rainbows are produced by the reflection of light
through rain drops.
155. Light switches in our homes are connected in parallel
series.
156. Generators convert mechanical energy into electricity.
157. Modern incandescent bulbs do not contain filaments made
of copper.
158. Trout is not a sea fish.
159. Epiphytes are a plant that grows upon another plant.
160. Hepatitis is the inflammation of liver.
161. Meningitis is inflammation of membrane surrounding the
brain.
162. Equinox is the time when the sun appears vertically
overhead at noon at the equator.
163. Joseph Aspdin is the inventor of cement.
164. Neurology is the science of Nervous system.
165. Biometry is the application of statistics in the study
of Biology.
166. Aviculture is the rearing and breeding of birds.
167. Malaria is caused by Plasmodium.
168. Goitre is caused due to deficiency of Iodine in diet.
169. Typhoid is caused by Salmonella Typhosa.
170. Black hole is a hypothetical region of space having a
gravitational pull so great that no mater or
radiation can escape from it.
171. Fungicide is used against moulds and fungi.
172. The science which deals with heredity is known as
Genetics.
173. Insulin is used for the treatment of Diabetes.
174. Yuri Gagarin is the first space man.
14
175. The distance between the earth and the sun is called
Astronomical unit.
176. The study of chemical processes in living organisms is
called Biochemistry.
177. The first computer virus invented by two Pakistani
brothers is called the brain virus.
178. Severe deficiency of vitamin C results in Scurvy.
179. Plant cells manufacture their food due to the presence
of chlorophyll.
180. Mitosis is a type of cell division where in the number
of chromosomes in the daughter cell are
the same.
181. Blood cells are of three types.
182. The ultraviolet rays cause sunburn.
183. Xylem and Phloem are conducting tissues.
184. Carbohydrates are cheapest and most ready source of
energy.
185. Enzymes are responsible for chemical digestion of food.
186. Plasma is the fluid part of the blood in which the
cells are suspended.
187. Haemoglobin combines with oxygen and transport to
different cells of the body.
188. Neutron is the negative charged particle in an atom.
189. Hydrogen is the lightest gas.
190. Mercury is the smallest planet of the solar system.
191. Image of the object is formed on the retina of the eye.
192. Barometer is used for measuring the pressure.
193. Monomer of proteins is Amino Acids.
194. Water transport in plants occurs within Xylem.
195. Underground horizontal stems are allied Rhizomes.
196. In the eye only Retina contains receptors for light
energy.
197. Plant Hormones control plant response to environment
stimuli.
198. Mitochondria are often called the powerhouse of the
cell.
199. The rate at which a current changes direction is called
its Line Frequency/Main frequency.
200. Diamond is an allotropic form of the element Carbon.
201. Speed of the wind is measured by Anemometer.
202. Ligament connects the muscle with the bone.
203. Polio is caused by virus.
204. Neptune is the coldest
planet of the solar system.
205. Eggshell is composed of calcium carbonate.
206. The most abundant element in the earth‘s crust is
oxygen.
207. The main constituent of Biogas is Methane.
208. Stalagmites are deposits of Calcium Carbonate.
209. Gigantism is the result of Hyper Pituitarism.
210. The purpose of computer is Manipulation of data.
211. The chemical name of washing soda is Sodium
Bicarbonate.
212. The main constituent of Sui gas is Methane.
213. Blue colour has the shortest wave length.
214. Glass is called Silica.
215. Ascorbic Acid is Vitamin C.
216. The solar system has 8 planets.
217. The second most abundant element in the earth‘s crust
is silicon.
218. The fastest revolving planet is Mercury.
219. Geysers are hot
springs that erupt hot waters and steam from time to
time.
220. The first simple microscope was invented by Hans
Janssen and Zachariah Janssen.
221. Hot liquid rock beneath the earth‘s surface is called
Lava/Magma.
222. Mitochondria are the power house of the cell.
223. Ability of the air to absorb long heat waves from the
earth after allowing the short waves from
15
sun to pass through it is known as Green House Effect.
224. Computer works on the principle introduced by the
Muslim scientist Musa al-Khwarizmi.
225. Coldest planet of the solar system is Neptune .
226. The rupture of red blood cells is called Eryptosis.
227. Muslim Scientist Ail bin Tabari is famous for his work
on Firdous al-Hikmah.
228. Haploid cells result from the process of meiosis.
229. All stars are not of the same colour.
230. The left lung has two lobes while the right lung has
three lobes.
231. The pulmonary veins return oxygenated blood to the
right atrium.
232. Our galaxy milky way is shaped like a large thick
concave lens with a large central bulge
233. DNA has a double helix structure while the RNA does not
have a double helix structure.
234. The normal temperature of Human Blood is 37C (98.60 F)
235. The liver is a part of gastrointestinal tract.
236. The major fossil fuel impurity is Sulphur .
237. Sphalerite is an ore of Zinc.
238. The most abundant element present in the sun is
Hydrogen.
239. The metal atom present in chlorophyll is Magnesium.
240. The gland responsible for the secretion of the hormone
estrogen is Ovary.
241. An element used in the doping of silicon for the
preparation of a p-type semiconductor is Boron.
242. A synthetic fibre which is a polyamide is Nylon.
243. Glycogen is a carbohydrate.
244. The cell structure that controls movements of material
into and out of the cell is Cell Membrane.
245. The unit that co-ordinates different devices of the
computer system are Control Unit.
246. Mastication is an example of Mechanical Digestion.
247. Botanically a fruit is a Ripened Ovary.
248. The vocal folds are part of the Larynx.
249. The famous book Al-Qanoon was written by the Muslim
scientist Abu Ail Sina.
250. The instrument used for the measurement of blood
pressure is Sphygmomanometer.
251. A mammal, which can fly is Bat.
252. A disease which is more common in men than in women and
is hereditary in character is Colour
Blindness.
253. Snow Leopard is an endangered animal species of Pakistan .
254. Cinnabar is an ore of Mercury.
255. Anabaena azolla is cyanobacterium.
256. The nuclear reaction taking place on the surface of sun
is Nuclear Fusion reaction.
257. Jabir bin Hayan prepared Sulphuric Acid.
258. The constituent elements of Brass are Copper and Zinc.
259. The conversion of non-diffusible substances into
diffusible ones by the action of enzymes is
called digestion.
260. Diamond is the purest naturally occurring crystalline
form of Carbon.
261. Caustic soda is extensively used for making Soap.
262. When a person can see nearer objects but not the
distant ones he is said to be suffering
from Myopia/Near-sightedness/Short sightedness.
263. Marble is a metamorphic rock.
264. Curie is a unit of Radioactivity
265. The brown colour of rust is because of Oxidation of
iron/formation of iron oxide.
266. The movement of food through oesophagus is by the
muscular action is known as Peristalsis.
267. Granite is a form of igneous rock.
268. Cellulose is the min chemical substance in the plant
cell wall.
269. Cell Nucleus was first discovered by Robert Brown.
16
270. Enzymes are organic catalysts made up of proteins.
271. Animals obtain carbohydrate mainly from Starch.
272. The minimum speed of a Pentium II computer is 233 MHz
273. According to recent classifications the living
organisms are divided into 5 kingdoms.
274. Glycolysis is a process of Respiration.
275. The unit that coordinates different devices of Computer
system is control Unit.
276. Seed is technically Ripened Ovule.
277. ADH is a hormone secreted by Posterior pituitary gland.
278. Permian Period belongs to Palaeozoic era.
279. Right kidney in man is slightly lower in position than
the left kidney.
280. Light is visible.
281. Steel is more elastic than rubber.
282. Pitch of man‘s voice is lesser than that of woman.
283. Diastolic blood pressure is lesser than systolic blood
pressure.
284. Guava contains more vitamin C than orange.
285. A light year is a unit of distance.
286. Mercury is heavier than lead.
287. Kangaroo Rat is a desert mammal which does not drink
water.
288. Aqua Regia is a mixture which can dissolve platinum.
289. The constituent elements of Bronze are tin and copper.
290. The deficiency of Thiamine (B1) causes Beriberi.
291. A nuclear reaction in which two or more than two
lighter nucleus are fused together to form a
relatively heavier one is calledNuclear Fusion.
292. Diamond is the purest naturally occurring crystalline
form of carbon.
293. The hormone secreted by adrenal cortex is
Corticosteroids (Cortisol & aldosterone)
294. The three colours combination which produces the
sensation of white light is Red, Green and
Blue.
295. A six feet tall lady can see her full image in a three
feet plane Mirror.
296. Vanadium, a steel gray corrosion resistant metal occur
naturally in oxide state.
297. Fibre optics cable carries data in the form of light.
298. Blue flame is hotter than red flame.
299. The falling of yellow leaves during autumn is the
seasonal time for plants to get rid of
accumulated wastes.
300. Friction is necessary evil.
301. Cancer can be treated by Chemotherapy and Radiotherapy.
302. The velocity of a moving object is least where the
pressure is greater.
303. The largest planet of solar system is Jupiter.
304. The temperature of the dead human body on Celsius scale
is 25C (Normally room Temperature)
305. The number of the spinal nerves in the man is 31 pairs.
306. A primary cell cannot be charged again.
307. Halos around the moon are formed because of the
phenomenon of dispersion.
308. Muscle stiffness is called by a disease called Tetanus.
309. Oil rises in a wick of oil lamp on account of a
property of matter called Capillary action.
310. Muslim scientist Ail al Tabari is famous for his work
on Firdous al-Hikmah.
311. The three elements needed for healthy growth of plants
are N (nitrogen), P (phosphorus) and K
(potassium).
312. Ammonium nitrate is not used for rice crop.
O2.
314. Ascorbic acid is a water soluble vitamin.
17
315. Lipase enzyme brings about hydrolysis of fats.
316. The solution if benzoic acid is used for seasoning of
food.
317. Influenza is caused by virus.
318. The energy possesses by water in a dam is potential energy.
319. The organ in the human body which is responsible for
the digestion of protein only is stomach.
320. Nicolas Leonard Sadi Carnot designed the first internal
combustion engine used to burn low
grade fuel.
321. William Gilbert was the scientist who asserted the
earth to be a huge magnet.
322. The metal known as quick silver is called Mercury.
323. Electrochemical cell converts the chemical energy into
electrical energy.
324. Yuri Gagarin was the first person to orbit the earth.
325. Water was discovered by Henry Cavendish.
326. To say in the sunlight while circling the globe at the
equator, one has to move with a speed
of 1670 km/hour.
327. Infrared waves have more wavelengths than the red
colour.
328. Liver produces bile which is involved in the breakdown
of fats.
329. A secondary cell can be charged again.
330. The study of human population is called Demography.
331. Human being belongs to species called Sapiens.
332. Defect of eye due to which nearly located objects are
not clearly visible is
called Hyperopia/Hypermetropia.
333. About 60-70% of the human body consists of water.
334. All of the oxygen that we breathe has been produces by
the splitting of water
during Photosynthesis.
335. The important ore of Chromium is Chromite.
336. The measurement of rainfall is made by an instrument
known as Rain gauge.
337. Oxidation means loss of electron.
338. Poplar is woody raw material which is used for the
manufacture of paper pulp.
339. Rectified spirit contains alcohol about 95%.
340. The Famous book; Al-Qanoon was written by the Muslim
scientist Abu Ail Sina
341. Basic metals can be converted into gold by artificial
nuclear radioactivity.
342. One of the main functions of the earth‘s ozone layer is
to filter out ultraviolet rays.
343. The alloy consisting of metals copper, zinc and nickel
is called Paktong/Alpaca/Nickel
Silver/German Silver
344. The instrument specially designed for recording
earthquake waves is called Seismograph.
345. The electrical device which converts sound energy into
electrical energy is Microphone.
346. The ore of mercury metal is Cinnabar.
347. The variation of blood flow can be heard thorough
Sphygmomanometer.
348. Alexander Fleming discovered penicillin.
349. Neil Armstrong was the first astronaut who first landed
on the surface of the moon.
350. Kangaroo rat is the desert mammal which does not drink
water.
351. Heat transfers from the sun to the earth through
Radiation.
352. Pitch of the cat sound is greater than the dog sound.
353. Ultraviolet light is not visible.
354. A guava contains more vitamin C than an orange.
355. Sound travels faster in iron than air.
356. Wheat
Bridge
357. Morphine can cause constipation and lowering of blood
pressure.
358. A convex lens is used for the correction of the
Hyper-phobia.
359. The nucleic acids are responsible for proteins
synthesis in the human body.
18
360. Entomology is the branch of zoology which deals with
the study of insects.
361. Beri Beri is the disease which is caused by the
deficiency of vitamin B1.
362. Oil rises in a wick of oil lamp because of a property
of matter, called Capillary action.
363. The production of genetically identical offspring is
called as Cloning.
364. Mercury is the fastest planet of the solar system.
365. Mercury metal is 13.5 times heavier than water.
366. Relative density of milk is measured by an instrument
known as Lactometer.
367. The temperature of a human body is measured by an
instrument known as Mercury
thermometer.
368. Gold and silver are known as coinage metals.
369. The amount of ozone in the atmosphere is expressed in
ppm (parts per million).
370. One of the country through which equator passes is Kenya
371. Max Planck received the Noble prize in Physics in 1918
for his discovery of energy quanta.
372. Bronze is made up of copper and tin
373. Addison‘s disease is caused by the excessive secretion
of Adrenocorticotrophic Hormone.
374. Margalla Hill is a branch of Himalaya Range
375. Humming bird belongs to a category called Endotherm
376. Insulin is secreted by Pancreas, thyroxin by Thyroid
gland, Adrenalin by Adrenal gland,
Oestrogen by Ovary, cortisol by Adrenal gland, Testosterone
by Testes of male and ovaries of female
377. Japan
is called Land of rising sun.
378. Rodenticides are used to kill rats.
379. Venus planet of our solar system is called as Morning
Star.
380. The diameter of the earth is 12742 km.
381. Insects are invertebrates
382. Opium is found in poppy.
383. Opium is used to make Heroine.
384. Kitab-al-Manadhir was written by Ibn-al-Haisham.
385. Speed of light is 300000 km/sec
386. Generators convert mechanical energy into electric
energy.
387. Dry ice is CO2.
388. Telephone was invented by Dr. Graham Bell.
389. Ammeter is the instrument which is used to measure
electric current.
390. Ascorbic acid is vitamin C.
391. Total number of bones in human face is 14.
392. The sky appears blue due to Tyndall Effect.
393. A, D, E, K are fat soluble vitamins
394. The composition of the mixture used for welding is
Copper Oxide and Aluminium.
395. Abu ail Sina, Al Beruni, Ibn Al Haisham belonged to
which 10th century.
396. Bakelite is not a Thermoplastic.
397. Haematite (a mineral) is the important source of iron.
398. Bauxite is the mineral of Aluminium.
399. Bronze is an alloy of copper and tin.
400. Skin is the largest organ of the body.
401. Vaccine for T.B is Bacillus Calmette Guerin (BCG)
402. Mitochondria is called the power house of the cell.
403. Persons with AB+
blood group are considered to be universal recipient.
404. Study of life in outer space is known as Exobiology.
405. The name of the common mineral salt present in sweat is
Sodium Chloride.
406. Sensitive layer of the eye is Retina.
407. Laughing gas as the composition of Nitrogen and Oxygen.
19
408. Dr. Abdus Salam of Pakistan was one of the
contributors of the unification of Electromagnetic
force and weak nuclear force.
409. CAT triplet in DNA codes for valine.
410. The chance of diabetic baby born to parents both
heterozygous normal is ¼.
411. Inheritance of acquired characters is not an art of
Darwinism.
412. Role of biotechnology in the production of food is
based on Fermentation.
413. Founder of modern astronomy was Nicolas Copernicus.
414. The instrument which measures very high temperature is
Pyrometer.
415. The science which deals with study of manners and
customs of people is Ethics.
416. Dry ice is Solid Carbon Dioxide.
417. Chemical name of vinegar is Dilute Acetic Acid.
418. Deficiency of Pyridoxine decreases haemoglobin
production.
419. Orbital period of the planet Mercury around the sun is
88 days.
420. The most splendid and the most magnificent
constellation on the sky is Orion.
421. ―Black holes‖ refer to Collapsing objects of high
density.
422. Eugenics is the study of altering human beings by
changing their genetic components.
423. The position of earth in its orbit when it is at its
greatest distance from the sun causing northern
summer is called Aphelion.
424. Ionosphere layer make the radio transmission possible.
425. Television signals are converted into light signals by
Transistor.
426. Most of Asteroids lie in asteroid belt between the
orbit of Mars and Jupiter.
427. The number of spark plugs needed in a diesel engine is
0.
428. The half-life of a radioactive element is 8 days. It
takes 8 days to reduce it from 10mg to 5 mg.
429. The term ―Blue Shift‖ is used to indicate Doppler
Effect in which an object appears bluer when
it is moving towards the observer or observer is moving
toward the object.
430. Kilowatt-hour is a unit of Power.
431. Fuel used in a Fast Breeder Reactor is Uranium
Plutonium Oxide.
432. Monsoon is caused by Revolution of earth.
433. Atmospheric layer ionosphere helps in radio
communication.
434. A moderator is used in nuclear reactor in order to slow
down the speed of the neutrons.
435. Sedimentary rocks are Porous.
436. Gypsum is a non-metallic mineral.
437. Ozone layer prevents the ultraviolet radiation from
entering the atmosphere.
438. The phenomenon of Aurora Borealis, the display of red
and green lights in northern hemisphere
is due to radiations from Ionosphere.
439. Oasis is associated with Desert.
440. Quartz crystal in quartz watches work on the principle
called Piezo-electric effect.
441. The fruits with seed, like banana, are called
Parthenocarpic fruits.
442. Animal which captures and readily kills living animals
for tis food is called Predator.
443. In a railway track, two rails are joined end in end
with a gap in between them to avoid accidents
due to expansion.
444. Al-Qanoon is the famous book of Ibn-e-Sina in which
human physiology and medicine are
discussed.
445. Copper can be converted into gold by Artificial
Radioactivity.
446. In winter an iron pipe feel colder than a wooden
window. This is because wood is non-conductor.
447. The echo (reflected sound) will be distinctly heard
only at ordinary temperatures if the distance
of the reflecting surfaces from the source of sound is at
least 56 ft.
448. It is possible to recognize a person in the dark by
simply hearing hiss unique voice. It is because
of the Pitch.
20
449. When a ray of sunlight enters a dark room, its straight
path becomes visible because of dust
particles hanging in the air. It is because light is
Transparent.
450. The principle used in radar is the same as that of
sonar. In radar we use radio waves; whereas in
sonar we use Ultrasonic.
451. Parsec is a unit of distance.
452. The German or nickel silver is composed of
approximately 60% copper, 20% nickel and 20%
zinc.
453. The temperature of the dead body is the temperature of
the place where it is kept.
454. Cusec is the unit for measuring the flow of
liquids/flow rate, equal to one cubic foot per second.
455. The deepest place on earth is Mariana trench.
456. Twinkling of stars is caused by Refraction of light.
457. Magnifying power of a simple microscope can be
increased by decreasing focal length of the
lens.
458. A very important practical application of properties of
matter is hoeing or ―godi‖ practiced by
the farmers. This property of matter is called Capillarity.
459. It is observed that the total pressure exerted by air
on the man of average size is around 14.7 lb.
wt. per square inch. But the man feels quite comfortable. It
is because of an equal and opposite
pressure acts from inside.
460. A nuclear reactor is a device used to carry out
controlled nuclear reaction whereas GM counter
is a device used to detect nuclear radiation.
461. A body can escape the gravitational pull of the earth
if it is thrown up with a velocity of 7 miles
per sec.
462. Night vision is possible with the help of Infrared
Rays.
463. Myopia is a defect of human eye. It can be corrected by
using a lens called concave lens.
464. Walnuts can be broken in the hand by squeezing two
together but not one. It is because of work
done.
465. The instrument which is specially designed for
recording earth quake wave is called
seismograph which measure earth quake waves on a Richter
scale.
466. Fossils found in the lowest geological strata are
generally most primitive.
467. Evolution can be described as a continuing process.
468. Mutation is the only source new alleles.
469. Polygenic characteristic are controlled by Multiple
Genes.
470. Digestion involves ingestion, digestion, absorption and
elimination.
471. In humans, most nutrient molecules are absorbed by the
small intestine.
472. The energy needed to fuel essential body processes is
called Basal metabolism.
473. Inhaled air passes through Bronchiole in the last.
474. Hermaphroditism is a form of sexual reproduction.
475. Cobalt is a metal which is strongly attracted by a
magnet.
476. Hepatitis A is transmitted to different individuals by
Faeces.
477. The unit that coordinates different devices of the
computer system is Control unit.
478. The approximate intensity level of the sound which can
cause damage is 100 decibel (dB).
479. Fuse wire is made of 63% tin and 37% lead.
480. The unit of photosynthesis in green plants is called
Quantosome.
481. The property by virtue of which metals can be beaten
into thin sheets is known as Malleability.
482. The sky appears blue because the earth‘s atmosphere
Reflects blue light.
483. Gamma rays are Higher energy rays emitted by
radioactive elements.
484. The radiation that is used in magnetic resonance
imaging (MRI) is in the infra-red range.
485. Lead is used in storage batteries.
486. The gas produced during the fermentation of Biomass is
Methane.
487. Biogas is the common name of Natural Gas.
21
488. Bacteria help in the process of fermentation of
biomass.
489. One thousand watt power is called as 1 kilowatt.
490. The meter installed in our homes measure electricity in
KWh.
491. Unis of electricity consumed by 2500 watt
air-conditioner in one hour are 2.5 units.
492. Gas bills are charged in CGS and BTU.
493. In BTU system, one BTU is equal to 1055 joule.
494. Air is present in the atmosphere of earth up to the
height of 200 kilometres.
495. All forms of energy that we use are ultimately
transformed into Heat energy.
496. The gas which acts as a glass of greenhouse is Carbon
dioxide.
497. Google is the largest search engine of internet.
498. Carbon dioxide is used in the preparation of soft
drinks.
499. World‘s largest flower auction is held in Aalsmeer.
500. All the plant life is based upon the compounds, which
are made up of Oxygen, Carbon and
Nitrogen.
501. Huge white ball in the sun almost consists of Hydrogen.
502. Charcoal is made by heating wood.
503. In blood, the percentage of water is 90%.
504. As the temperature of ice rises, the ice melts and its
density increases.
505. Water is a universal solvent for Biochemical Reactions.
506. The temperature of the water below the solid ice layer
is 4 degree centigrade.
507. The volume percentage of nitrogen in air is 78%.
508. The composition of oxygen in air is kept constant by
the process of Photosynthesis.
509. Nitrogen occurs in plants and animals in the form of
Protein.
510. Air contains volume of carbon dioxide approximately
0.03%.
511. The gases which are used by divers as an artificial
atmosphere are helium and oxygen.
512. Noble gases are extremely unreactive.
513. The second most abundant metal found in the earth‘s
crust is Iron.
514. The iron content in plant tissue is normally between
50-250ppm.
515. Chernobyl nuclear
reactor lies in Russia .
516. Chernobyl
nuclear plant was destroyed in 1986 due to Failure of cooling system.
517. Radioactive source must be kept in Lead Container.
518 In Brazil
alcohol is used as fuel for vehicles.
519. Voltmeter can be made by modification in Galvanometer.
520. The device used for the measurement of current, voltage
and resistance is AVO meter.
521. In the name of multimeter ―AVO‖, V stands for Voltage.
522. Silicon is a Semiconductor.
523. Paper is an insulator.
524. For sending sound waves at large distance, Radio Waves
are used.
525. The carrier waves used for the radio transmission have
the frequency up to 30 KHz.
526.Video camera is used to convert Picture into electrical
signals.
527. In a colour television, the colours are green, red and
blue.
528. The waves used for sending signals to the satellite
from ground station are Micro Waves.
529. First telegraph signal was transmitted in 1901.
530. In a telephone receiver, Magnet is placed under the
diaphragm.
531. Nowadays, the international communication and
transmission is being done through the waves
known as Microwaves.
532. Modern Bicycle was invented by Staley.
533. Coulomb is the unit of Electric Charge.
534. For certain reasons, some people develop cloudy areas
in one or both lenses. This defect is
called Cataract.
22
535. In order to prevent the corrosion of iron pipes they
are often coated with a layer of zinc. This
process is termed asGalvanization.
536. In a reactor, cadmium rods re used for Absorbing
Neutrons.
537. Detergents dissolved in water help in cleaning clothes
by reducing the surface tension of water.
538. The swing of a spinning cricket ball in the air can be
explained on the basis of Bemoulli‘s
Theorem.
539. The absorption of ink by blotting paper involves Capillary
Action phenomenon.
540. Materials for rain proof coats and tents owe their
water proof properties to Surface Tension.
541. For being able to see three-dimensional pictures we
have to use An Epidiascope.
542. Water has maximum density at 4 degree centigrade.
543. The highest recorded air temperature in the world in
degree Celsius is 57.
544. The instrument that measures wind speed is the
anemometer.
545. The theory of expanding Universe was first propounded
by Hubble.
546. Used tea leaves contain Quinine.
547. A lake starts freezing because of the cold atmosphere.
It will first freeze at the top surface.
548. The Sun remains visible for some time after it actually
sets below the horizon. This happens due
to Atmospheric Refraction.
549. An iceberg is floating in sea. One tenth of its mass
will remain above the surface of water.
550. Bat has the highest upper limit of audible range.
551. ―Hotline‖ is A telecommunication link between the
rulers of countries.
552. Most of the ozone is concentrated in the Stratosphere.
553. The cow‘s milk contains 80% of water in terms of
percentage.
554. Numismatics is the study of Coins.
555. Measles is a viral disease.
556. Vitamin C is present in Citrus Fruits.
557. Leukaemia is a Blood Cancer.
558. Haemophilia is a hereditary disease.
559. Diamond is the hardest material.
560. Lead ball falls through water more slowly than through
air because of the viscous force in water.
561. Polaroid‘s are used for Photoelasticity.
562. Scalding with steam is more severe than scalding by
boiling water because Steam contains more
energy than boiling water.
563. Cooking oil can be converted into vegetable ghee by the
process of Hydrogenation.
564. Stainless steel is an alloy of Iron, Chromium and
Nickel.
565. Optical fibres work on the principle of Total internal
reflection.
566. Water vapour beyond the dew point results in
Condensation.
567. The main chemical substance present in the bones and
teeth of animals is Calcium Phosphate.
568. The Green House Effect is caused by an excess of Carbon
dioxide.
569. Bats can also fly in dark because they are capable of
taking the help of Ultrasonic Waves.
570. Gold is found in its original form.
571. Green vegetables have high iron content.
572. The fat content in buffalo milk is 10%.
573. Whale has the largest egg.
574. The rear view mirror of a motor vehicle is Convex.
575. A post mortem study usually involves an analysis of
liver.
576. Bio fertilisers are nitrogen-fixing micro-organisms
which can enrich soil.
577. Tincture of iodine consists of A solution of iodine in
alcohol.
578. The only planet of solar system which has water vapours
is Neptune .
579. The major part of natural gas, petroleum and coal
consist of Methane.
580. Gypsum is used for cement.
23
581. Chromium is obtained from Chromite.
582. Silica is used in glass-making.
583. Human population has become double during the last 45
years.
584. At present population growth rate in Pakistan is
1.573%.
585. In Pakistan ,
the nuclear power stations are built at Karachi
and Chashma.
586. Plutonium is used as Fuel for nuclear fission.
587. Uranium-235 is used in the fission process.
588. The solar energy falling on the atmosphere of earth is
almost 1.4 kilowatt per square meter.
589. The large plates of solar panels are painted Black.
590. The temperature of the semi-molten rocks about 10 km
below the surface is 200 degree
Centigrade.
591. Cataract is a disease of eye.
592. Rayon is made of Cellulose.
593. Meter per second is a unit of Velocity.
594. The greatest number of compounds is formed by the
element of Carbon.
595. The major component of honey is Glucose.
596. The working principle of a washing machine is
Centrifugation.
597. Oxygen is present in the largest amount in terms of per
cent by mass in the earth‘s crust.
598. Radioactivity was first discovered by Henry Becquerel.
599. Helium gas is commonly used in balloons and airships.
600. The process of elimination of water from any system is
called Dehydration.
501. Huge white ball in the sun almost consists of Hydrogen.
502. Charcoal is made by heating wood.
503. In blood, the percentage of water is 90%.
504. As the temperature of ice rises, the ice melts and its
density increases.
505. Water is a universal solvent for Biochemical Reactions.
506. The temperature of the water below the solid ice layer
is 4 degree centigrade.
507. The volume percentage of nitrogen in air is 78%.
508. The composition of oxygen in air is kept constant by
the process of Photosynthesis.
509. Nitrogen occurs in plants and animals in the form of
Protein.
510. Air contains volume of carbon dioxide approximately
0.03%.
511. The gases which are used by divers as an artificial
atmosphere are helium and oxygen.
512. Noble gases are extremely unreactive.
513. The second most abundant metal found in the earth‘s
crust is Iron.
514. The iron content in plant tissue is normally between
50-250ppm.
515. Chernobyl nuclear
reactor lies in Russia .
516. Chernobyl
nuclear plant was destroyed in 1986 due to Failure of cooling system.
517. Radioactive source must be kept in Lead Container.
518. In Brazil
alcohol is used as fuel for vehicles.
519. Voltmeter can be made by modification in Galvanometer.
520. The device used for the measurement of current, voltage
and resistance is AVO meter.
521. In the name of multimeter ―AVO‖, V stands for Voltage.
522. Silicon is a Semiconductor.
523. Paper is an insulator.
524. For sending sound waves at large distance, Radio Waves
are used.
525. The carrier waves used for the radio transmission have
the frequency up to 30 KHz.
526. Video camera is used to convert Picture into electrical
signals.
527. In a colour television, the colours are green, red and
blue.
528. The waves used for sending signals to the satellite
from ground station are Micro Waves.
529. First telegraph signal was transmitted in 1901.
24
530. In a telephone receiver, Magnet is placed under the
diaphragm.
531. Nowadays, the international communication and
transmission is being done through the waves
known as Microwaves.
532. Modern Bicycle was invented by Staley.
533. Coulomb is the unit of Electric Charge.
534. For certain reasons, some people develop cloudy areas
in one or both lenses. This defect is
called Cataract.
535. In order to prevent the corrosion of iron pipes they
are often coated with a layer of zinc. This
process is termed asGalvanization.
536. In a reactor, cadmium rods re used for Absorbing
Neutrons.
537. Detergents dissolved in water help in cleaning clothes
by reducing the surface tension of water.
538. The swing of a spinning cricket ball in the air can be
explained on the basis of Bemoulli‘s
Theorem.
539. The absorption of ink by blotting paper involves
Capillary Action phenomenon.
540. Materials for rain proof coats and tents owe their
water proof properties to Surface Tension.
541. For being able to see three-dimensional pictures we
have to use An Epidiascope.
542. Water has maximum density at 4 degree centigrade.
543. The highest recorded air temperature in the world in
degree Celsius is 57.
544. The instrument that measures wind speed is the
anemometer.
545. The theory of expanding Universe was first propounded
by Hubble.
546. Used tea leaves contain Quinine.
547. A lake starts freezing because of the cold atmosphere.
It will first freeze at the top surface.
548. The Sun remains visible for some time after it actually
sets below the horizon. This happens due
to Atmospheric Refraction.
549. An iceberg is floating in sea. One tenth of its mass
will remain above the surface of water.
550. Bat has the highest upper limit of audible range.
551. ―Hotline‖ is A telecommunication link between the
rulers of countries.
552. Most of the ozone is concentrated in the Stratosphere.
553. The cow‘s milk contains 80% of water in terms of
percentage.
554. Numismatics is the study of Coins.
555. Measles is a viral disease.
556. Vitamin C is present in Citrus Fruits.
557. Leukaemia is a Blood Cancer.
558. Haemophilia is a hereditary disease.
559. Diamond is the hardest material.
560. Lead ball falls through water more slowly than through
air because of the viscous force in water.
561. Polaroid‘s are used for Photoelasticity.
562. Scalding with steam is more severe than scalding by
boiling water because Steam contains more
energy than boiling water.
563. Cooking oil can be converted into vegetable ghee by the
process of Hydrogenation.
564. Stainless steel is an alloy of Iron, Chromium and
Nickel.
565. Optical fibres work on the principle of Total internal
reflection.
566. Water vapour beyond the dew point results in
Condensation.
567. The main chemical substance present in the bones and
teeth of animals is Calcium Phosphate.
568. The Green House Effect is caused by an excess of Carbon
dioxide.
569. Bats can also fly in dark because they are capable of
taking the help of Ultrasonic Waves.
570. Gold is found in its original form.
571. Green vegetables have high iron content.
572. The fat content in buffalo milk is 10%.
573. Whale has the largest egg.
25
574. The rear view mirror of a motor vehicle is Convex.
575. A post mortem study usually involves an analysis of
liver.
576. Bio fertilisers are nitrogen-fixing micro-organisms
which can enrich soil.
577. Tincture of iodine consists of A solution of iodine in
alcohol.
578. The only planet of solar system which has water vapours
is Neptune .
579. The major part of natural gas, petroleum and coal
consist of Methane.
580. Gypsum is used for cement.
581. Chromium is obtained from Chromite.
582. Silica is used in glass-making.
583. Human population has become double during the last 45
years.
584. At present population growth rate in Pakistan is
1.573%.
585. In Pakistan ,
the nuclear power stations are built at Karachi
and Chashma.
586. Plutonium is used as Fuel for nuclear fission.
587. Uranium-235 is used in the fission process.
588. The solar energy falling on the atmosphere of earth is
almost 1.4 kilowatt per square meter.
589. The large plates of solar panels are painted Black.
590. The temperature of the semi-molten rocks about 10 km
below the surface is 200 degree
Centigrade.
591. Cataract is a disease of eye.
592. Rayon is made of Cellulose.
593. Meter per second is a unit of Velocity.
594. The greatest number of compounds is formed by the
element of Carbon.
595. The major component of honey is Glucose.
596. The working principle of a washing machine is
Centrifugation.
597. Oxygen is present in the largest amount in terms of per
cent by mass in the earth‘s crust.
598. Radioactivity was first discovered by Henry Becquerel.
599. Helium gas is commonly used in balloons and airships.
600. The process of elimination of water from any system is
called Dehydration.
601. Sparkling red colour after the blast of fire cracker is
due to the presence of Sulphur .
602. The chemical name of aspirin is Acetylsalicylic acid.
603. Animal fat has the highest calories per gram.
604 The commonly present element in the artificial fertilizer
is Potassium, Nitrogen and Phosphorus.
605. Potassium nitrate is used in fertilizers.
606. The inherited traits of a person can be investigated by
the study of Deoxyribonucleic acid.
607. Silicon is extensively used in electronics.
608. When a bullet is fired upwards vertically, it gains in
Potential energy.
609. The mixture of Acetylene and oxygen gases is required
in gas welding.
610. Isobars are the lines connecting the places having same
Atmospheric pressure.
611. The velocity of wind is related to Pressure gradient.
612. The acid present in the sour milk is Formic acid.
613. The most important stimulant in tea leaves is Caffeine.
614. Dolly was the name of first cloned sheep.
615. The smallest living cell is that of a Mycoplasma
(bacterium)
616. We lose consciousness if blood flow to the brain is cut
off more than 5 sec.
617. Menopause usually occurs between 40 to 45 years.
618. Platypus and Echidnas are the only monotremes, or
mammals that lay eggs.
619. Film is that part of camera which is analogue to the
retina in the human eye.
620. 72-80 is the average adult pulse rate.
621. Magnetic resonance is the modern tool for imaging brain
tumours.
622. The acid used in a car battery is sulphuric acid.
26
623. After drinking contaminated water, you would be most
apt to develop symptoms of Typhoid
fever.
624. In eye donation, Cornea of donor‘s eye is utilized.
625. Alzheimer is a disease of Brain.
626. Cell was discovered by Robert Hooke.
627. A body is taken from Earth to Moon. Its weight will
Decreases.
628. Brass is an alloy of Copper and Zinc.
629. Mineral essential for the coagulation of blood is
Magnesium.
630. Milk is an example of Emulsion.
631. Iron is the most abundant transition metal.
632. Hydrometer is used to determine specific gravity of
liquids.
633. Convex lenses are used for the correction of
Long-sightedness (Hyperopia)
634. A transformer is used to Increase or decrease AC
voltage.
635. The stones formed in human kidney consist mostly of
Calcium oxalate.
636. Most of the explosions in mines occur due to the mixing
of Methane with air.
637. A mobile phone sends and receives messages through
Radio waves.
638. Fax machine receives the signal and give its output
through the Printer.
639. The procedure of crushing the gallstone and kidney
stone by laser is called Lithotripsy.
640. Laser is used to produce an image of One dimension.
641. Three dimensional image formed by laser is called
Photograph.
642. The first laser ever used is Semiconductor laser.
643. Ordinary light spreads in all directions.
644. Optical fibres are the fine strands of Glass.
645. The satellites which revolve in such an orbit, so that
they move with earth rotation are
called Geo-stationary satellites.
646. The elements which emit radiations have atomic number
greater than 82.
647. In a normal healthy body, the number of red cells or
erythrocytes in each cubic millimetre of
blood is 5.0 m.
648. The average life of a red blood cell in the body is
about 120 days.
649. DNA is a class of nucleic acids.
650. Cellulose is a Carbohydrate.
651. After long periods of use, a gray spot develops on the
inside of a bulb. This is because
the tungsten filament evaporates and collects there.
652. Ice cubes are added to a glass of pure water and a
glass of a pure alcohol. The ice would
be Floating in alcohol and sinking in water.
653. Protein which renders a cell less susceptible to attack
by viruses is called Chloromycetin.
654. The pigment involved in photosynthesis activity is
called Chlorophyll.
655. The chemical part of the dye that absorbs light and
produces colour is called photo chrome.
656. A nuclear reactor harnesses nuclear energy by
Controlled chain reaction.
657. Eyes are tested by dilating the pupils with a very
dilute solution of Atropine.
658. Phenol is used as a raw material in the manufacture of
foam used in mattresses, cushions, etc.
659. ECG is an instrument used for the disorder of Heart.
660. Carbon-14 is used for dating very old objects of
archaeological importance.
661. Lead is used in storage batteries.
662. Enzymes are Biological catalysts.
663. DNA finger-printing is the latest technology used in
Forensic science.
664. Potassium is used in the preparation of glass and soap
in the form of Carbonates.
665. Potassium phosphate is used in the preparation of
detergent.
666. In Chlorophyll, magnesium is present.
667. Calcium plays a vital role in blood clotting.
27
668. For water purification, Chlorine is used
669. Deficiency of calcium causes the impaired growth in
infants.
670. Wheat, rice, corn and maize are the best sources of
carbohydrates.
671. The human blood is divided into four groups.
672. The muscles, tissues and blood all are made up of
Proteins.
673. Iron is a part of haemoglobin which transports oxygen.
674. In thyroid glands iodine is required for the synthesis
of Thyroxin.
675. The amount of calories provided by egg is 150 K
calories/100gm.
676. Jupiter is the largest planet of solar system.
677. The mirror placed near the driver of a bus is Concave
mirror.
678. X-rays are used to disintegrate bladder stones.
679. The percentage of carbohydrates in the normal daily
food calorie requirement of an adult is
about 59%.
680. Impure blood is received in the heart in the right
auricle.
681. Plants take nitrogen in the form of Nitrate.
682. Washing soda in water behaves acidic.
683. The glad which maintains body temperature is the
Pituitary gland.
684. Peeled banana under normal condition is brittle.
685. Phrenology deals with sensory perception of animals.
686. Vinegar is produced by two steps, first fermentation of
sugar by yeast, second fermentation of
ethyl alcohol by bacteria.
687. The longest and the strongest bone in the human body is
Femur.
688. Red color has the longest wavelength and violet has the
shortest wavelength.
689. Chronometer is used to measure Time.
690. Carbon dioxide is used in fire extinguishers.
691. Hereditary disorders are the result of Defective DNA
nucleus.
692. Pure gold is 24 carat.
693. One horse power is equal to 746 watts.
694. Dynamo is a device that converts Mechanical energy into
electrical energy.
695. The minimum velocity required to escape from the
gravitational pull is 11.2 km/s.
696. Heavy water consists of Oxygen and heavy hydrogen.
697. Polio is a viral disease.
698. Ag is the symbol for silver.
699. Babbage is called the father of computer.
700. Dead red blood cells are stored in liver.
Oxygen
46.1% , 461,000
Silicon
28.2% , 282,000
Aluminum
8.23% , 82,300
Iron
5.63% , 56,300
Calcium
4.15% , 41,500
Sodium
2.36% , 23,600
Magnesium
2.33% , 23,300
28
Potassium
2.09% , 20,900
Titanium
0.565% , 5,650
Hydrogen
0.14% , 1,400
701. Spring tides occur on new moon and full moon days
because on these days Sun, moon and earth
are in a straight line.
702. Clayey soil is best suited for cotton.
703. The time interval between two beats of a normal human
heart is 1 second.
704. The material used for bleaching paper pulp is Sodium
hypochlorite.
705. Mercury has the smallest diameter.
706. The instrument, used for recording tremors of earth, is
known as Seismograph.
707. Ionosphere makes the radio transmission possible.
708. Colour of the skin is due to the presence of Melanin.
709. Natural rubber is a protein.
710. Concave mirror can be used to focus sunlight.
711. Liver secrets bile.
712. When an object is transferred from the earth to the
moon its mass remains unchanged.
713. The unit of sound is Decibel.
714. It is economical to transmit electric power at high
voltage.
715. Diamond does not have a tetrahedral structure.
716. The unit to measure the supersonic speed is Mach.
717. The application of the principles of genetics to the
improvement of human race is known
as Eugenics.
718. The penetration of x-rays through an object depends
upon the object‘s Density.
719. Using Ultrasound, we can determine the Structure of the
body.
720. The find the hidden secrets under the water, the ships
and submarines use the Sonar system.
721. The dirt in the dirty water can be separated by using
the Ultrasound.
722. Recording of brain waves from outer surface of head is
called E.E.G (Electroencephalograph).
723. The first rocket launched by Pakistan was Rahber.
724. The first Nuclear power plant in Pakistan was established at Karachi .
725. Sodium benzoate is used for preservation of food
grains.
726. Steel is more elastic than rubber because ratio of
stress to strain is more.
727. Haemoglobin makes the blood look red.
728. Mercury is extracted from Cinnabar.
729. Cattle-bone powder is used as fertilizer as it is rich
in Phosphorous.
730. Heating element of an electric heater Nichrome.
731. Dry sand appears bright while wet sand appears dark
because of Reflection.
732. Acid rain contains high levels of Sulphuric acid.
733. A woman‘s voice is shriller than a man‘s due to smaller
vocal chords.
734. The blood glucose level is commonly expressed as
Milligram per decilitre.
735. Soft drinks such as colas contain significant
quantities of Caffeine.
736. A small pouch containing silica gel is often found in
bottles of medicine in tablet or powder
form because silica gel absorbs moisture.
737. Fluorescent tubes are fitted with a choke. The choke
coil reduces current in the circuit.
738. For reproduction of sound, a CD (Compact Device) audio
player uses a Laser beam.
739. When a CD (Compact Disc used in audio and video systems)
is seen in sunlight, rainbow like
29
colours are seen. This can be explained on the basis of the
phenomenon of Reflection and diffraction.
740. If a U-238 nucleus splits into two identical parts, the
two nuclei so produced will
be Radioactive.
741. The total genetic material within an individual is
known as the Genome.
742. The part of the body directly affected by Pneumonia is
Respiratory system.
743. As the amount of clay in a soil increases, its water
retaining capacity increases.
744. ―O‖ blood group of human beings is a universal donor.
745. Amino acids are a product of the digestion of Protein.
746. Ptyalin is a starch digeting enzyme.
747. Pepsin, a digestive enzyme, is produced in the Stomach.
748. Milk is nearly a complete food by itself.
749. The acids turn the blue litmus paper Red.
750. Permanent magnets can be made from Cobalt.
751. Nights are cooler in the deserts than in the plants
because Sand absorbs heat more quickly than
the earth.
752. Atmospheric pressure exerted on the earth is due to the
Gravitational pull.
753. Fertilizer having high nitrogen content is Urea.
754. Potassium Carbonate is used for removing air bubbles
from the glass during its manufacture.
755. The chemical name for ―baking soda‖ is Sodium
Bicarbonate.
756. The snow on the mountains does not melt all at once
when it is heated by the sun because it
reflects most of the heat from the sun.
757. First time AIDS was identified in 1983.
758. Anthrax is a bacterial disease.
759. Blood is formed in bone marrow in human body.
760. Quark is the smallest part of the matter discovered by
the scientists.
761. Trachoma is a disease of the eye.
762. The heart of a normal adult human being weighs about
300 grams and that of woman 200
grams.
763. Heart pumps 5 litre blood per minute in a normal human
adult (at resting position).
764. The part of the body directly affected by Rikets is
bone tissue.
765. Histology is the study of tissues.
SCIENTIFIC REASONS FROM PAST PAPERS
(95 To 2011):
1) The Earth bulges out at equator. Why?
Ans: This is due to the shape of the earth. The earth is not
a true sphere but it is an ellipsoid.
The equatorial diameter of the earth is 12756.27 kms. While
its polar diameter is 12713.505
km. the difference between its equatorial and polar diameter
is about 43 kilometres. The
rotation of the earth on its axis produces a centrifugal
force which increases its equatorial
diameter. That is why earth bulges at the equator.
2) The Sun appears red at sunset and sunrise. Why?
Ans: The sun appears red at the time of sunset and sunrise
due to the scattering of light by
small particles of dust or smoke near the surface of the
earth. The light travels relatively
without hindrance that is why the sun appears red at the
time of sunset and sunrise.
3) The ozone layer in the atmosphere is necessary for our
survival. Why?
Ans: ozone layer in the atmosphere is very necessary for
plant and animal survival because it
is the absorber of ultraviolet rays which are very dangerous
for animal health. Ultraviolet rays
cause cancer of skin, spotting of plants etc. that is why
the ozone layer is necessary and
essential for animal as well as plant survival.
4) The sky from moon appears black. Why?
Ans: as the moon has no atmosphere, so the sky looks
completely black when viewed from
the moon.
5) Roads are bent inwards on curves. Why?
Ans: The roads are bent inwards on the curves and at the
turns because the bents avoid falling
outside and prevent the accidents.
OR
When an object turns in a circle it is influenced by a
centrifugal force which pushes it away
from the centre of the circle. When vehicles turn on a road
they fall outside under the
influence of centrifugal force. In this way there is danger
of falling or slipping out of road at a
turn. Roads are made in a way that these bent inward at the
turns to avoid falling outside and
to prevent accidents.
6) Australian continent has winter season when we have
summer season in Pakistan .
Ans: the earth on its axis is not at a vertical angle to its
orbit. It is inclined at an angle of
about. In this way when the northern hemisphere of the earth
is inclined to the sun and getting
direct sun rays, southern hemisphere is inclined away from
the sun and getting less direct
rays. Thus the northern hemisphere has summer season and
southern hemisphere has winter
season. Pakistan
is in the northern hemisphere while Australia is in the southern
hemisphere.
So when there is winter in Australia
there is summer season in Pakistan .
31
7) Meat takes longer to cook on mountains.
Ans: The meat takes longer time to cook on the mountains
because the atmospheric pressure
decreases with attitude and the boiling point of a liquid is
directly proportional to the
atmospheric pressure.
8) Water remains cool in earthen pitcher.
Ans: This occurs due to the process of evaporation. Water
gets cooled on evaporation. As the
earthenware pitcher is concerned, they have small pores.
Water tends to come out of pores
and evaporates which results in cooling effect on the
earthenware and water.
While in the metal pots there are no pores and evaporation
does not take place. Besides metal
has tendency to absorb heat that why water does not get
cooled in a metal pot.
9) Ice and salt mixture is used as a freezing agent by
manual ice-cream makers.
Ans: In manual ice-cream making a mixture of salt and ice is
always used because salt has
capacity to reduce the temperature of ice by decreasing its
freezing point. That‘s why ice and
salt mixture is used as freezing agent in manual ice cream
making.
10) It is not advisable to sleep under trees during the
night.
Ans: During night the plants release carbon dioxide (CO2)
which is a poisonous gas and
injurious to health. That is why it is not advisable to
sleep under trees during night.
11) Why the green house operators paint their glass roofs
white in summer?
Ans: White colour is the reflector of light and it absorbs
less heat as compared to other
colours. As in summer there is already very hot season and
heat is not required to that level.
That is why the green-house operators paint glass roofs
white in summer season.
12) Water boils quicker on mountains.
Ans: On Mountains the pressure of the air is low due to
height, as the air pressure decreases
with altitude. In this way, water boils quicker on mountains
at temperature less than 100
degree centigrade, which is the boiling point of water at
ground level.
13) Rainbow is produced in the sky after rainfall and
sunlight.
Ans: After rain, many droplet of water travel in the
atmosphere. When sun rays fall on these
droplets, dispersion of water occurs and droplets act as
prism and produce a spectrum of
seven colours. That‘s why a rainbow is seen in the sky after
rain.
14) Milk is considered as an ideal food.
Ans: Milk is considered as an ideal food due to following
reasons:
a) It contains all constitute of balanced diet.
b) Milk contains fat.
c) Milk has high nutritional value because it contains
proteins as well as minerals.
32
15) Lunar eclipse last much longer than solar eclipse.
Ans: Lunar eclipse last longer than the solar eclipse
because the length of the earth‘s umbral
shadow cone is more than three times the average distance
between the moon and the earth,
so the shadow is relatively wide at the point where the moon
crosses it.
16) Goitre is common in hilly areas.
Ans: Goitre is common in hilly areas because there is
deficiency of Iodine in the water.
17) Detergents are better cleaning agents.
Ans: A detergent consists of hydrophilic and hydrophobic
ends. In case of dirt the detergent
pushes the dirt off the wet surface of the fabric. The
washing machine provides the agitation.
18) Decomposers are important for life.
Ans: Decomposers break down animal waste and dead organisms
in order to get energy and
release free nutrients back into the ecosystem.
OR
Decomposers break down organics into nutrients, which can be
used by living organisms to create
new life.
19) Places near sea are cooler in summer.
Ans: Sea water keeps the temperature moderate. In the summer
season the places located near sea are
cooler due to the lower temperature of water.
20) Colour blindness is more common in men than women.
Ans: Women have the sex chromosomes XX, while men have the
chromosomes XY. The gene for
normal colour vision is found on the X-chromosome. If a
woman has one X-chromosome with the
gene and one without it, she will not be colour blind. On
the other hand, a man with an X-chromosome that is missing the gene has no
'backup'. He will definitely be colour blind. Colour blind
women have both X-chromosomes missing the colour vision
gene. This is less probable
mathematically than having just one X-chromosome missing the
gene.
21) Light colours absorb less heat therefore these are not
heated as much as the black colour.
Ans: Dark colours do not exactly absorb more heat, but they
do convert a higher percentage of light
into heat. In the sun with a dark coloured shirt it gets hot,
where a lighter coloured shirt would not get
nearly as hot. This is due to the amount of light being
absorbed by the colour. The lighter the colour
the smaller is the range of visible light being absorbed and
converted into heat. White objects reflect
all visible light, where black objects absorb all visible
light.
22) Rain water is more fertile than water from tube well.
Ans: Rain water is more fertile because it contains many
salts and nitrogen dissolved from the
atmosphere.
33
23) The manhole covers are generally round.
Ans: Manholes, which interconnect underground sewerage
pipes, and serve as a point of entry for
cleaning the pipes, are located at every major sewer pipe
junction, and are capped with round
manhole covers. The reason for the circular construction of
these covers is, quite simply, that covers
of any other shape would fall through the manholes by virtue
of their varying diameters. Circular
manhole covers do not vary in width, or in diameter, as is
the case with these other shapes, thus
remaining in place despite the street traffic running
roughshod over them.
24) Clothes of a moving dancer bulge.
Ans: The clothes of a moving dancer bulge outside due to the
centrifugal force which tends to move
away from the centre.
25) People are advised not to stand near fast moving train.
Ans: One should not stand beside a fast moving train because
of the strong pressure of air which
carries along. A man can fall in this pressure.
26) The image of a tree is inverted on the bank of a lake.
Ans: The water of lake acts as a mirror. According to the
laws of light, mirror forms inverted images.
27) Polar star is always seen in the north.
Ans: It is because the Polar Star (North Star) is closest to
the location of the celestial North Pole.
28) We never see birds urinating.
Ans: The birds do not have a urinary system like other
living beings which possess urinary excretory
organs. In the birds the urine is excreted from body without
special organs.
29) Pasteurized milk has more nourishment than the ordinary
boiled milk.
Ans: Pasteurized milk is obtained by heating milk at a
temperature of 60 degree Celsius for 30
minutes. In this way the TB bacteria are killed without
damaging the milk protein. Thus pasteurized
milk has more nourishment than ordinary boiled milk.
30) Bees die when they sting human being.
Ans: Their stingers are actually ovipositors, tubular
structures extending from the abdomen that
sometimes contain eggs. When the barbed stinger is left
inside the victim, the honeybee mortally
tears her abdomen in the process. They leave their stingers
in the wound with a tiny venom sac
attached. Fortunately, only about one out of a hundred people
are allergic to bee sting, but allergic
reactions can be very serious.
31) Cloudy nights are usually warmer than the clear ones.
Ans: The clouds serve as a barrier and prevent the loss of
heat. Thus the warm temperature is
maintained.
34
32) Why do some people snore?
Ans: Some people snore during their sleep because the
breathing action produces sound. This is so
because the pharynx or the windpipe offers resistance to the
air taken in or expelled.
33) Why do we sometimes sleep walk?
Ans: Sleep walk is a sort of disorder of sleep in which a
person starts walking during his sleep. The
sleeper walks and performs complex activities automatically
without regaining consciousness.
34) Climbers bend forward while climbing mountain.
Ans: While climbing a mountain, a climber bends his body
forward in order to keep the centre of
gravity of his body within two thirds portion. According to
this principle the Pisa
Tower
falling.
35) Why climbers get their food by climbing on other trees?
Ans: The climbers are mostly parasites and they cannot
manufacture their food. Therefore, they
climb on other trees and get food from them.
36) Mars is called red planet.
Ans: Mars is called the red planet because its colour is red
due to the desert like surface.
37) Vitamin D is the essential component of the body.
Ans: Vitamin D is necessary for body because it is essential
for bone formation and retention of
calcium in the human body. Vitamin D also protects the
teeth.
38) The weight of the object is less at the equator than at
the poles.
Ans: The weight of an object is the product of mass and
force of gravity. The equatorial diameter is
more than the polar diameter. Thus, the force of gravity is
more at the poles and the weight is more
there.
39) The dogs pant, the birds open their mouth and the
elephants move rapidly their ears.
Ans: All of them do not sweat; they use the above mentioned
mechanisms to cool themselves.
40) A geostationary satellite appears standstill to a viewer
on the equator of earth.
41) Why do the stars twinkle?
Ans: The light from the stars travels through different
layers of space of varying densities. Therefore,
the light rays deviate from their original path. Further,
these layers are not stationary but keep on
moving. This leads to the twinkling of stars.
42) On what days do we have equal days and nights all over
the world? And why?
Ans: On 23 September and 21 March we have equal days and
nights all over the world. This is so
because on these days, the rays of the sun fall vertically
on the equator at noon. Both the poles
receive equal rays of the sun. As a result, exactly one-half
of each hemisphere receives the sun‘s rays.
This makes day and night equal.
35
43) Every fourth year has 366 days. Explain.
Ans: One revolution of the earth around the sun takes 356
days and 6 hours. But we consider a year
as consisting of only 365 days and ignore 6 hours. In four
years the difference becomes as much as
24 hours or one day. Hence, to every fourth year we add one
day. That year of 366 days is known as
leap year.
44) Why are igneous rocks called primary or parent rocks?
Ans: Igneous rocks are formed when the molten material from
volcanoes gets solidified. This
material is liquid, hot and sticky which moves towards the
surface through cracks and joints. All
other rocks derived from these rocks. Hence, they are called
primary or parent rocks.
45) Why are the areas lying between the Arctic
Circle and the North Pole in the Northern
Hemisphere and the Antarctic Circle
and the South Pole in the Southern Hemisphere very cold?
Ans: These areas are very cold because the sun does not rise
much above the horizon. Therefore, its
rays are always very slanting which emit minimum heat. These
areas being very cold are called
Frigid Zones.
46) Why are the three hot regions of the world-equatorial
forests, savannah lands and hot deserts-not
found in Europe ?
Ans: The three hot regions of the world-equatorial forests,
savannah lands and hot deserts-are not
found in Europe because Europe
is the only inhabited continent situated entirely outside the tropics.
47) Why is the lowest layer of the atmosphere in contact
with the earth‘s surface, the warmest?
Ans: The lowest layer of the atmosphere in contact with the
earth‘s surface is the warmest because
the atmosphere is heated mainly from the below.
48) Why does the temperature above the ocean and land masses
vary even on the same latitude?
Ans: Temperature above the oceans and land masses varies
even on the same latitude because of the
differential heating of land and water, i.e., land mass is
heated and cooled more rapidly and to a
greater degree than water.
49) Why are marine animals able to live at great depths than
marine plants?
Ans: As marine animals do not depend upon sunlight for their
survival, they are able to live at great
depths where there is permanent darkness.
50) Why do trees of coniferous forests possess needle-like
leaves?
Ans: The needle-like leaves limit transpiration and thus
enable conifers to grow in the drier areas.
51) Why do equatorial forests appear evergreen?
Ans: In equatorial forests trees often shed a few leaves or
shed their leaves seasonally, but most of
the trees retain their leaves for most of the time so that
the forests appear evergreen.
52) Why is petroleum often called black gold?
Ans: Petroleum is often called black gold because of its
great demand in the modern industry and for
domestic use. It provides fuel for heat and lighting,
lubricant for machinery and raw material for a
number of industries.
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53) Why are the kangaroos called marsupials?
Ans: Marsupial means broad-pouch. Since kangaroos have a
pouch-like fold of skin near the stomach
in which they carry their young ones, they are called
marsupials.
54) Why is platypus considered a strange animal?
Ans: Platypus is a strange animal because it is an
animal-bird that survives under water, walks on the
ground and digs tunnel under the ground. It is a four-legged
animal that lays eggs like a bird. It is
found in Australia .
55) Why is a person in moving vehicle thrown forward when
the vehicle stops suddenly?
Ans: A person in a moving vehicle is in a state of motion.
When the vehicle suddenly stops his body
tends to remain in a state of motion due to inertia and he
is thrown forward.
56) Earth is continuously pulling moon towards its centre.
Why does not the moon fall on to the
earth?
Ans: it is so because the gravitational attraction of the
earth provides the necessary centripetal force
to the moon for its orbital motion around the earth due to
which the moon is revolving around the
earth.
57) Which of the two-glass or rubber is more elastic and
why?
Ans: Glass is more elastic than rubber because for a given
applied force per unit area, the strain
produced in glass is much more than that produced in rubber.
58) Animal like camel can easily walk in the desert sand
while other animals like donkeys, dogs and
horses cannot. Explain.
Ans: The camel has very broad and large feet. As a result of
the large surface area in contact with the
ground, it exerts less pressure on the sand and sinks only
slightly in it. Other animals have smaller
feet which exert more pressure on the sand. As a result,
they sink more in the sand and cannot walk
easily in desert.
59) Why does a small quantity of liquid assume spherical
form?
Ans: A small quantity of liquid assumes a spherical form due
to surface tension which tends to
reduce the surface area. A given mass will acquire minimum
surface area if it assumes a spherical
shape.
60) Why does an iron needle float on clean water but sink
when some detergent is added to this
water?
Ans: Due to surface tension, the free surface of liquid at
rest behaves like a stretched membrane.
When an iron needle floats on the surface of clean water,
its weight is supported by the stretched
membrane. When some detergent is added to this water, its
surface tension decreases. As a result of
it, the stretched membrane on the surface of water is
weakened and is not able to support the weight
of needle. Hence the needle sinks in such water.
61) Why is cooking quicker in a pressure cooker?
Ans: The boiling point of water depends upon the pressure on
its surface. Steam produced inside the
cooker builds up pressure thereby raising the boiling point
of water, which results in quick cooking.
62) Why does steam cause more severe burns than boiling
water?
Ans: The amount of heat (latent heat) possessed by steam is
much greater than the amount of heat
possessed by water at the same temperature. Therefore, steam
causes more severe burns than boiling
37
water.
63) Why does ice not melt readily when salt is sprinkled
over it?
Ans: When salt is sprinkled over ice, some of it dissolves.
As dissolution of the salt is accompanied
by absorption oh heat. The temperature of the system falls
below 0 degree Celsius. Hence, ice does
not melt readily.
64) It is difficult for firemen to hold a hose, which ejects
large amount of water at a high velocity.
Why?
Ans: the water which comes out of the fireman‘s hose carries
large momentum as its velocity is very
high. The equal and opposite reaction force pushes the
fireman backwards with a great speed
satisfying the law of conservation of momentum. As a result,
it is difficult for the fireman to hold the
hose.
65) In the outer space astronauts talk to each other through
radios. Why?
Ans: sound waves need a material medium for its propagation.
There is no air in space and hence,
sound waves cannot travel. However, radio waves can travel
through space. The astronauts can see
each other because light, like radio waves, can travel
through vacuum.
66) Sonar scanners are used by doctors. Explain.
Ans: sonar scanners send out ultrasonic waves, which are
reflected by body tissue and organs. From
the pattern of reflections, a computer can build up an image
of the internal structure which is vital for
diagnosis.
67) Why the flash of lightning is seen before the sound of
thunder is heard?
Ans: the velocity of light is much greater than that of the
sound. Therefore, flash of lightning is seen
before the sound of thunder is heard.
68) Bats have poor eyesight but are able to home their prey
with great accuracy. Also, dolphins can
avoid fishing nets and can detect fish at night. Explain
Ans: Bats emit high frequency (1, 20,000 Hz) sound waves and
listen with their sensitive ears for any
echoes. From the time taken to hear the echo and from the
nature of sound received. Bats are able to
estimate the distance and the type of surroundings. This
process is known as echolocation. Same
process is used by the dolphins.
69) When low flying aircraft passes overhead, we sometimes
notice a slight disturbance on our TV
screen. Why is it so?
Ans: a low flying aircraft reflects TV signal. Due to the
interference between the direct signal and the
reflected signal, there is disturbance on the TV screen.
70) In automobiles, why are convex mirrors used to see the
traffic from behind?
Ans: Convex mirrors are used in automobiles because they
form erect and diminished images of the
object. Thus, it helps the drivers to get a wider field of
view of the traffic coming from behind.
71) Why is mirage formes in the deserts?
Ans: A mirage is formed owing to total internal reflection.
To the observer at a distance, the reflected
image of the object appears behind the reflecting surface,
as if the object were in front of it, but
actually it is just an illusion.
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72) What will be the colour of grass in blue light?
Ans: Grass will appear blackish in colour in blue light
because it has the property of absorbing all
other colours except its own colour. The blue rays falling
on grass will be absorbed by it, and it will
appear dark coloured.
73) A bird perches on a bare high power line and nothing
happens to it. A man standing on the
ground touches the same line and gets a fatal shock. Why?
Ans: When bird perches on a live high power line, no current
passes through the body of bird because
there is no potential difference between live wire and the
body of bird as the potential of bird‘s body
is the same as that of wire.
When a man standing on the ground touches the same wire then
due to a large potential difference
between his hands and feet, a large current flows through
his body to the earth.
74) During lightning it is safest to be inside a car rather
than under a tree or in the open. Give reason.
Ans: When a person is in the open or under the tree, the
lightning passes through his body to the
earth. On the other hand, for a person inside a car, the car
provider shielding and the electric field
inside the car is zero, thus lightning does not affect the
person inside it. The lightning actually passes
through the metallic body of the car to the earth without
affecting the person sitting inside it.
75) Why is earthing desirable for electric appliances?
Ans: Earthing helps the current move into the earth in the
event of short-circuit, without giving a
shock to the user.
76) Why does a perspiring man feel relief when air flows by
his side?
Ans: The air flowing by the side of a perspiring man
quickens the pace of evaporation of perspiration
from the body of that person, and the resultant loss of heat
from his body causes the cooling sensation
which provides relief to him.
77) Why is magnet always made of soft iron?
Ans: Magnet is always made of soft iron because
‗magnetisation‘ and ‗demagnetisation‘ both are
possible in soft iron.
78) Why are telephone wires between two poles kept loose?
Ans: Telephone wires are kept loose between two poles so
that they are protected from being broken
due to expansion and contraction caused by the change of
temperature in summers and winters.
79) X-rays penetrate through the flesh but not through
bones. Why?
Ans: The penetrating power of X-rays depends upon the
potential difference between the cathode and
the anode of X-ray tube. The X-rays produced can penetrate
through light element like flesh of
human body but they are unable to penetrate through heavier
elements like bones.
80) What is a black hole? Why is it called so?
Ans: A black hole is a super dense planetary material formed
due to the death of a star of mass more
than five solar masses.
It is called black hole because any particle or photon
approaching its surface is just swallowed by it.
It appears black, as radiation is neither emitted nor
reflected by it.
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81) Why do water pipes burst in severe cold winters?
Ans: Water freezes in pipes during winters, when the
temperature goes below 0 degree Celsius (i.e.,
freezing point of water). It expands and in the process
exerts pressure on the water pipes, thereby
sometimes bursting them.
82) Most aircrafts and ships have their front shape pointed.
Why?
Ans: The shape of many objects, viz. aeroplanes, rockets,
ships, etc. moving through air or water, are
designed in such a way that friction can be reduced between
the objects and air/water. Such type of
body is known as streamlined and the process is known as
streamlining.
83) An athlete runs some distance before taking jump, why?
Ans: An athlete runs a certain distance before actually
jumping in order to increase his speed, and
thereby, his inertia of motion. This increased inertia of
motion enables him to jump a longer distance.
84) It is difficult to drown in the Dead
Sea . Why?
Ans: The water of Dead Sea
has a salt content of 27%. Therefore, its density is much greater than that
of ordinary sea water and it also offers a greater upthrust.
Hence, the body weighs less than an equal
volume of Dead Sea water
and is thus, able to float.
85) Why aquatic animals have soft skeleton unlike those of
the terrestrial animals?
Ans: The density of animals and fish living in water is
almost the same as the density of water.
Therefore, their weight is almost completely balanced by
buoyancy. That is why they do not need
massive skeleton like those of terrestrial animals.
86) Why does a swimming pool appear less deep than it really
is?
Ans: When rays of light start from the bottom of a pool and
travel from water to air, they are
refracted away from the normal because they travel from a
denser medium to a rarer medium. As a
result, a virtual image of bottom is formed above the
bottom. Hence, a swimming pool appears less
deep than it really is.
87) Why is electrical wiring in parallel better?
Ans: electrical wiring in parallel is better because all the
lines will have the same potential difference
and if one line gets fused the other lines remain
unaffected.
88) It is easier to swim in sea water than in river water.
Explain.
Ans: The density of sea water is more than that of the river
water. Therefore, the weight of sea water
displaced by the swimmer is more. Thus, buoyant force of
upthrust on the swimmer increases,
making it easier to swim in sea water.
89) A cold compress is applied on the forehead of a person
suffering from high fever. Why?
Ans: Evaporation causes cooling. As the water evaporates, it
absorbs heat from the forehead and
helps in reducing the temperature.
90) A man with a load his head jumps from a high building.
What will be the load experienced by
him.
Ans: Zero, because the acceleration of his fall is equal to
the acceleration due to gravity of the earth.
91) Why is spring made of steel and not copper?
Ans: The elasticity of steel is greater than that of copper.
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92) Why is it easier to spray water to which soap is added?
Ans: Addition of soap decreases the surface tension of
water. The energy for spray is directly
proportional to surface tension.
93) A piece of chalk when immersed in water, emits bubbles.
Why?
Ans: Chalk consists of pores forming capillaries. When it is
immersed in water, the water begins to
rise in the capillaries and air present there is expelled in
the form of bubbles.
94) Why does a liquid remain hot or cold for a long time
inside a thermo flask?
Ans: Because of the presence of air, which is poor conductor
of heat, in between the double glass
walls of a thermos flask.
95) Why is the boiling point of sea water more than that of
pure water?
Ans: Sea water contains salts and other impurities with
different points which jointly rise its boiling
point.
96) Why is it recommended to add salt in water while boiling
grams?
Ans: By addition of salt the boiling point of water gets
which helps in cooking.
97) Why is soft iron used as an electromagnet?
Ans: Because it remains magnetic only till the current
passes through the coil and loses its magnetism
when the current is switched off (principle of electric
bells)
98) Why does ink leak out of a partially filled pen when
taken to a high altitude?
Ans: As we go up the pressure and the density of air go on
decreasing. Partially filled pen leaks when
taken to a higher altitude because the pressure of air
acting on the ink inside the tube of the pen is
greater than the pressure of air outside.
99) Why does some liquids burn while others do not?
Ans: A liquid burns if its molecules can combine with oxygen
of the air with the production of heat.
Hence, oil burns but water does not.
100) Oil and water do not mix. Why?
Ans: i) Molecules of oil are not bigger than that of water
and therefore do not mix easily.
ii) Molecules of water are polar, i.e. they have opposite
charges at two ends whereas oil molecules do
not; as a consequence they tend to stay away from water
molecule.
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7. Differences
1. Artery & Vein
Artery
i) Arteries are blood vessels which transport blood away
from the heart.
ii) Arteries have thick vascular walls.
iii) The inside bore or lumen of arteries is narrow.
iv) Arteries carry oxygenated blood with the exception of
pulmonary artery.
v) The walls of arteries are more elastic.
vi) The blood is under great pressure in the arteries.
vii) Arteries are generally deeply placed.
viii) Arteries end in the capillaries.
Vein:
i) Veins are the blood vessels which always carry blood
towards heart.
ii) Veins have thin muscular walls.
iii) The inside bore or lumen of veins is wide.
iv) Veins carry deoxygenated blood with the exception of
pulmonary veins.
v) The walls of veins are less elastic.
vi) The blood is under less pressure in the veins.
vii) Veins are generally superficially placed.
viii) Veins start from the capillaries.
2. PNP and NPN Transistor
1. NPN has higher electron mobility than PNP. Therefore, NPN
bipolar transistors are often more
favoured than PNP transistors.
2. NPN is easier to create from silicon than PNP.
3. The main difference of NPN and PNP is the base. One is
just the opposite of the other.
4. With the NPN, a P-dope semiconductor is the base, while
with the PNP, the ‗base‘ is a N-dope
semiconductor.
3. Electronic & Static Electricity
Electronic Electricity
i) This is electricity in motion.
ii) It involves flow of electrons.
iii) It has high voltage.
Static Electricity:
i) This is electricity at rest.
ii) It does not involve flow of electrons.
iii) It has low voltage.
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4. Concave & Convex Lens
Concave Lens
i) It is the lens which is narrower in the centre and broader
towards the corners.
ii) When a beam of light strikes a concave lens all the rays
after passing through it diverge.
iii) It gives mostly virtual image.
iv) They are also called diverging lenses.
Convex Lens:
i) It is the lens which is narrower towards the corners and
broader towards the centre.
ii) When a beam of light strikes a convex lens all the rays
after passing through it converge at a single
point.
iii) Mostly real images are formed except when the ray of
light passes through it when object is
palced between optical centre and focus.
iv) They are also called converging lenses.
5. Absorption & Adsorption
Absorption
i) Absorption is a process in which a substance takes up
another substance, such as blotting paper
(solid) absorbing water (a liquid). OR Adsorption and
absorption are two different things. Absorption
is the chemical integration of one chemical into another.
When you drink a glass of water, you are
absorbing it, as the water becomes part of you.
Adsorption:
i) Adsorption is a process in which a substance adheres to
the surface of another substance.
Adsorption is important in some types of catalysis, notably
where gases adsorb on metal surfaces.
The reaction is then made easier by a consequent lowering of
activation energy. OR Adsorption
occurs when one substance holds another via physical bonds.
If you spill a glass of water on your
shirt, it is adsorbed as the fibres will hold the water
until heat dries out the shirt.
6. Fats & Oils
Fats
i) are solid at room temperature
ii) made by animals, mostly
iii) are more saturated
Oils:
i) are liquid at room temperature
ii) are made by plants, mostly
iii) are less saturated
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Hypoglycaemia:
i) The fall in sugar level in the blood below the normal
physiologic level known as Hypoglycaemia.
Normal physiologic range of sugar in blood is 60-90mg% at
fasting and 120-140 mg% at random.
ii) It is treated by giving intravenous glucose.
iii) It causes mental confusion, visual problem and often
coma etc.
iv) It causes weakness and increases in food desire.
Hyperglycaemia:
i) Hyperglycaemia is a condition in which blood sugar level
rise above its normal range.
ii) It is treated by exercise, medicine or by intravenous
insulin therapy.
iii) It causes weakness, calf pain, unhealed wounds and
kidney problem.
iv) It causes excessive urination, dryness of lips and
increased thirst etc.
2. Epidemic & Endemic
Epidemic:
i) If at one place and times a great number of people suffer
from a disease is known as epidemic.
ii) It can travel from one place to another.
iii) Examples: Influenza, Smallpox, Cholera etc.
Endemic:
i) If a disease persists in a particular locality, certain
area or one region, it is known as endemic
disease.
ii) It cannot travel from one place to another place.
iii) Example: Goitre in iodine deficient areas.
3. Herbivores & Carnivores
Herbivores
i) The animals eating green plants, grass and fodder are
known as Herbivores.
ii) Animals have specific digestive system to digest leaves,
plants and fodder.
iii) The teeth are specifically designed to cut and chew
leaves, plants and fodder.
iv) Jaw movement is specific for side motion.
v) Examples: goats, cattle, sheep, buffalo, cow etc.
Carnivores:
i) The animals eating flesh and meat are known as
carnivores.
ii) Digestive enzymes are specific.
iii) Their teeth are short and to cut and chew leaves,
plants pointed especially for flesh eating.
iv) Jaw movement is specific for up and down movement.
v) Examples: Tiger, dog, cat, lion etc.
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4. Respiration & Photosynthesis
Respiration
i) Respiration is a catabolic process in which compounds are
broken down.
ii) In this process carbohydrates are broken down into
simpler compounds.
iii) The end-products for this process are CO2 and H2O.
iv) In respiration Oxygen enters the plant body and CO2 is
released.
v) It occurs during both day and night. Light is not
necessary for this process.
vi) In respiration energy is released from food material.
Photosynthesis
i) It is an anabolic process in which compounds are formed.
ii) In this process carbohydrates are manufactured.
iii) The end-product of this process is simple
carbohydrates.
iv) In photosynthesis CO2 enters the plant and O2 is
released.
v) It occurs during day time only. Light is essential for
this process.
vi) It is energy consuming process.
5. Pollination & Fertilization
Pollination
i) It is a process involving transfer of pollens form male
reproductive organ to female reproductive
organ of plants.
ii) It occurs in flowering plants.
iii) The products of pollination are seed.
iv) It takes place through animals, birds, insects, wind and
water.
Fertilization:
i) In fertilization fusion of egg and sperm occurs.
ii) It occurs markedly in animals.
iii) The product of fertilization is zygote.
iv) It takes place by physical contact and mating of male
and female.
Thermoplastics
i) Plastics that can be melted again and again are known as
thermoplastics.
ii) They behave just like wax.
iii) These plastics can be shaped again and again.
iv) Examples: Nylon, PVC, Teflon etc.
Thermosetting Plastics:
i) Plastics that can be melted only once are known as
thermosetting plastics.
ii) They become hard after melting.
iii) These plastics cannot be shaped again and again.
iv) Examples: Polyesters and Bakelite.
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Lunar & Solar Eclipse
Lunar Eclipse
i) It occurs when the earth comes between moon and sun.
ii) Moon goes through series of partial eclipses when moon
comes out of umbral region of earth‘s
shadow.
iii) Earth lies in umbral region at total eclipse when earth
lies exactly between moon and sun and its
shadow covers the whole moon.
Solar Eclipse
i) It occurs when moon comes between earth and sun.
ii) Partial eclipse of sun occurs as in Penumbra can see a
part of the sun.
iii) At the total eclipse of the sun, the shadow of moon
which it throws on earth consists of an umbra
and penumbra people on earth who are in umbral region cannot
see the sun.
Asteroid & Meteorite
Asteroid:
i) The small rocky objects which are orbiting the sun
between orbits of Mars and Jupiter are known
as asteroids.
ii) Its origin is concentrated to the remains of planets
that fell apart.
iii) Asteroid means star like but these are known as minor
planets.
Meteorite:
i) Tiny chunk of material floating in space, which can also
enter the earth‘s atmosphere and become
meteor are known as meteorites.
ii) It may originate by the disintegration of comet.
iii) A falling star (Meteor) is seen as a streak of light in
sky.
Renewable & Non-renewable resources
Renewable Resources
i) Renewable resources are used continuously and can be used
again and again.
ii) Major examples are: air, water, soil, wildlife, forests,
fish etc.
iii) These resources support millions of people all over the
world.
iv) Renewable resources are constantly renewed by
bio-geochemical cycles of nature.
Non-renewable Resources
i) Non-renewable resources cannot be used again and again
after their consumption.
ii) Major examples include: Coal, oil, natural gas etc.
iii) These resources cannot support millions of people all
over the world.
iv) Non-renewable resources are being exhausted day by day
because their demand rises. Due to
worldwide demand of fossil fuels, its supplies are
declining.
OR
Renewable resources-
1) the resources that can be renewed by reproduction are
called renewable resources.
2) Renewable resources are inexhaustible.
3) Renewable resources are not affected by the human
activities.
4) All biotic resources are renewable.
5) For example: air and water.
46
Non-renewable resources-
1) the resources that are present in fixed quantities are
called non-renewable resources.
2) Non-renewable resources are inexhaustible.
3) Non-renewable resources are affected by human activities.
4) Some abiotic resources are non-renewable.
5) For example- fossil fuels and minerals.
Endothermic & Exothermic Reaction
Exothermic Reaction
i) Energy is drawn in from the external environment, causing
its surroundings to loose heat, or "cool
down."
ii) The endothermic chemical reaction creates a product that
has a higher energy level than the
original materials, causing the reactant's stored energy to
decrease. (In scientific terms, the reactants
have "less total enthalpy" than the product.)
iii) The resulting product of the reaction is less stable
because, the higher the energy bond, the less
strength its molecules possess.
iv) Most endothermic reactions are not spontaneous.
v) Example: Melting ice. In order for ice to melt, it needs
to draw in the heat (energy) from its
surroundings. The ice becomes less stable as it responds to
the increased heat. The ice stored energy
decreases. The end product is water, which has a higher
energy level than the ice.
Exothermic Reactions
i) Exothermic chemical reactions cause their surroundings to
warm up by giving off heat.
ii) The reactants contain more stored energy than the
product because energy from external sources is
not required, but given off. This gives the product more
stability due to the lower amount of energy
needed. (In this case, the reactants have a "greater
total enthalpy" than the product.)
iii) Exothermic reactions are usually spontaneous.
iv) Example lighting a match. When the head of the match is
struck, it results in the spontaneous
release of stored energy (heat) from the reactants into the
surroundings. The flame that is produced
has a lower level of energy than the match and the striking
surface because the reaction is giving off
stored energy and not required to draw energy in from its
surroundings
Star & Planet
Star
i) Stars are self-luminous heavenly bodies.
ii) They do not revolve around the sun.
iii) They are usually stationary.
iv) Examples: fixed stars, binary stars.
Planet:
i) Planets are rocky non-luminous bodies.
ii) They revolve round the sun.
iii) They usually move.
iv) Examples: Mercury, Venus, Jupiter etc.
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Nuclear Fission & Fusion
Fission:
i) Lighter atoms are fused together at a very high
temperature to form heavier elements.
ii) It is difficult to carry out on the earth.
iii) It has no nuclear waste problem.
iv) It requires cheaper and abundant elements.
v) Not possible at concerning scale as high temperature is
needed to start it.
Fusion:
i) Heavier unstable atoms are broken down to produce energy.
ii) It is easy to carry out on the earth.
iii) It has nuclear waste radioactivity disposal problem.
iv) It requires expensive and rare elements.
v) Possible to commercialize under controlled measure.
RAM
i) It stands for random access memory.
ii) It is an optical disc, where data and information is
stored permanently.
iii) RAM is the primary storage media.
iv) RAM is the primary storage device from which the system
boots.
v) RAM is stored on RAM chip.
vi) The data or information stored on it can be written on
or it can be erased.
ROM
i) It stands for read only memory.
ii) It is that part of CPU, where temporary information is
stored.
iii) RIOM is the secondary storage media.
iv) System does not boot from ROM.
v) ROM is stored on a compact disc.
vi) The data or information stored on it neither be written
on, nor it can be erased.
BIT & BYTE
A bit is defined as: a single basic unit of information,
used in connection with computers and
electronic communication. All modern computers store and use
data in digital form. The smallest unit
of storage and measurement is one binary digit, therefore
its name.
A byte, pronounced ‗bite‘, is the next size up basic unit of
measurement for information storage,
usually consisting of eight bits. These 8 bits are grouped
together to form a byte that is, a total or 8
grouped bits representing one character of data.
Therefore, so far we have two basic units of measuring
digital information storage that have different
capacities, they are:
• 1 Bit
• 8 Bits equal 1 Byte
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CU & ALU
CU
i) It stands for Control Unit.
ii) Control unit controls overall activates of computer.
iii) CU does not perform the functions of calculations.
ALU
i) It stands for arithmetic logic unit.
ii) It performs arithmetic and logical operations.
iii) ALU performs functions of addition, subtraction,
multiplication and division.
Hardware & Software
Hardware:
i) All the physical components of computer which can be
touched, measured have weight and occupy
space are collectively called computer hardware etc.
ii) Examples of hardware are: keyboard, mouse, joy stick,
scanner, printer, CPU etc.
Software:
i) Software can be defined as a set of instructions and
codes written in a defined manner. In other
words software are pre-written programs, which control the
operation of computer.
ii) Examples of software are; DOS, windows, UNIX, XENIX,
Linus, JAVA, Oracle, Antivirus etc.
PC/Minicomputers & Mainframe computers
PC:
i) It is a small computer based on microprocessor.
ii) One user can use it at a time.
iii) These are very low priced computers. An individual can
afford it.
iv) User friendly software are used to operate this
computer.
v) Minicomputers were launched in 1959 by Digital Equipment
Corporation (DEC)
vi) Minicomputers are also made by Data General, Hewlett-Packard
& IBM
Mainframe Computers:
i) The largest computers called mainframe computers are the
oldest category of computer system.
ii) They are capable of great processing speed and data
storage.
iii) These are always kept in air-cooled rooms.
iv) They are mainly used in banks, airlines and industrial
companies.
Email & Snail Mail
Snail mail:
i) "Snail mail" is a term used to refer to mail
that is sent in the traditional way — through the postal
service — rather than by email, fax, or other electronic
means of communication.
ii) It is called "snail mail" because it can be
very slow, as is a snail. Snail mail generally takes 2 or 3
days to go from origin to destination, if not many
more,
iii) Snail mail has gone out of fashion for simple letters,
though it is still necessary for sending
packages, or legal documents that require signatures.
49
Email:
i) Email is electronic mail which is very quick means of
communication through computers and
telephone line.
ii) Email can be sent instantly.
iii) With email, a message is sent directly from a user's
mail program to another person's email
address. Though many email messages simply contain words,
they may also include photos or other
digital files, such as songs, or links to websites.
Apes & Monkeys
Apes:
i) Apes do not have tail.
ii) Apes have rounded nasal openings.
iii) Apes generally have bigger brains and larger bodies
than monkeys.
iv) Apes do not have web foot.
v) Apes are bigger in size.
vi) Apes are: Humans, Chimps, Gorillas, Orangutans and
Gibbons.
Monkeys
i) Monkeys have tails.
ii) Monkeys have slanted nasal openings.
iii) Monkeys have web foot.
iv) Monkeys are smaller in terms of size
v) Monkeys are all primates non-apes and non-prosimians
(lemurs)
Hydrostatics & Hydrodynamics
Hydrostatics:
i) Hydrostatics is a branch of science which deals with
physical behaviour of liquids at rest.
ii) The consideration of liquids at rest, involves problems
of buoyancy and flotation, pressure on
dams and submerged devices, and hydraulic presses.
Hydrodynamics:
i) Hydrodynamics is the branch of science which deals with
behaviour of liquids in motion.
ii) The study of liquids in motion is concerned with such
matters as friction and turbulence generated
in pipes by flowing liquids, the flow of water over weirs
and through nozzles, and the use of
hydraulic pressure in machinery.
Comet & Meteor
Comet:
i) Comet is a collection of gas, dust, and volatile ice that
travel around the sun, generally in very
eccentric orbit.
Meteor:
i) Meteor is a streak of light seen in the night sky signify
the burning up in earth‘s atmosphere of
inter-planetary material.
50
Barrage & Dam
Barrage:
i) Barrages are constructed not at a much height but at a
low height.
ii) Barrages are single purpose constructions i.e. for
irrigation.
iii) Electricity cannot be produced in barrages.
iv) It is constructed on plains.
v) Sukkur barrage is an example.
Dam:
i) Dams are constructed at higher elevation or at a height.
ii) Dam is multipurpose. It acts as reservoir, control
flood, and for irrigation.
iii) Dam is constructed to generate electricity.
iv) It is impossible at ground level.
v) Tarbella dam is an example.
Isotopes:
These are the elements having same atomic number but
different mass number. They have
the same atomic number because the number of protons inside
their nuclei remains the same.
The difference in their mass number is due to the difference
in their number of neutrons.
Isobars
Where Isotopes are chemically the same and physically
different, the converse is true in
Isobars. That is isobars are elements, which are chemically
different but physically the same.
So, isobars are atoms of different elements having the same
atomic mass but different atomic
number. Since their number of electrons is different, their
chemical properties are different.
The light nuclei have unstable isobars. Heavy nuclei have
stable isobars and these occur in
pairs. Suppose the number of protons of one isobar matches
with that of another they are
called as mirror-nuclides of each other.
Autopsy & Biopsy
Autopsy:
i) An autopsy is the dissection and analysis of a dead
subject.
ii) , autopsies are limited to the deceased and there are
two kinds of autopsy; External
examination and internal examination.
iii) Autopsy is performed for medico-legal purpose.
Biopsy:
i) A biopsy is a medical test in which cells, tissue, or
fluid is removed for examination.
ii) Biopsy is not limited to only living people because they
are routinely taken from organs
that are going to be used for transplantation.
iii) Autopsy is performed for diagnosis purpose.
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Mitosis & Meiosis
Mitosis:
i) Mitosis takes place within somatic cells (cells that make
up the body).
ii) One single division of the mother cell results in two
daughter cells.
iii) A mitotic mother cell can either be haploid or diploid.
iv) The number of chromosomes per nucleus remains the same
after division.
v) It is preceded by a S-phase in which the amount of DNA is
duplicated.
vi) In mitosis, there is no pairing of homologous chromosomes.
vii) There is no exchange of DNA (crossing-over) between
chromosomes.
viii) The centromeres split during anaphase.
ix) The genotype of the daughter cells is identical to that
of the mother cells.
x) After mitosis, each daughter cell has exactly same DNA
strands.
Meiosis:
i) Meiosis takes place within gamete cells (sex cells).
ii) Two divisions of the mother cell result in four meiotic
products or haploid gametes.
iii) A meiotic mother cell is always diploid.
iv) The meiotic products contain a haploid (n) number of
chromosomes in contrast to the (2n)
number of chromosomes in mother cell.
v) In meiosis, only meiosis I is preceded by a S-phase.
vi) During prophase I, complete pairing of all homologous
chromosomes takes place.
vii) There is at least one crossing-over or DNA exchange per
homologous pair of
chromosomes.
viii) The centromeres do separate during anaphase II, but
not during anaphase I.
ix) Meiotic products differ in their genotype from the
mother cell.
x) After meiosis, each daughter cell has only half of the
DNA strands.
Hard water & Heavy Water
Hard Water:
i) Hard water is that type of water which does not form
lather easily.
ii) Its formula is H2O.
iii) Hard water is not used in nuclear power plants.
Heavy Water:
i) Heavy water is deuterium oxide in which hydrogen of water
is replaced by its heavier
isotope, Deuterium.
ii) The formula of heavy water is D2O.
iii) Heavy water is used in nuclear power plants.
Climate & Weather
Climate:
i) Climate is the normal weather conditions for an area
during a season or a year.
ii) Climate of an area is described by means of an average
means of an average of the
statistics of the various weather factors over a period of
time, normally 30-years.
Weather:
i) Weather is the condition of the atmosphere at any one
place and time.
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ii) Weather is described by air, temperature and humidity,
wind speed and direction, cloud
amount and precipitation, sunshine and visibility.
Cardiac & Skeletal Muscles:
Cardiac Muscles:
i) Cardiac muscles are present in the heart only.
ii) They have centrally placed nuclei.
iii) They never fatigue.
iv) They are composed of long fibres.
v) They are under involuntary control.
Skeletal Muscles:
i) Skeletal muscles are present in the skeleton of the body.
ii) Nuclei are not centrally placed in skeletal muscle.
iii) They can fatigue.
iv) They are not composed of long fibres.
v) They are under voluntary control.
Haze & Smog
Haze:
i) The dust particle smoke etc. that may be visible in
atmosphere close to the earth‘s surface
is known as Haze.
ii) It does not affect natural visibility.
iii) It does not occur particularly near coastal areas.
Smog:
i) It is a mixture of solid and liquid fog as well as
particles of smoke. It is formed when
humidity is high.
ii) Smog reduces visibility.
iii) It occurs near coastal areas.
Enzyme & Hormone
Enzyme:
i) These are organic catalysts produced in the protoplasm of
all living cells.
ii) These are mostly protein in nature.
iii) They control all biochemical reactions of the cell.
iv) These are present in all cells and show their activity
there.
Hormone:
i) These are organic substances produced in places away from
their functional sites.
ii) These are mostly acids.
iii) They promote and inhibit growth, flowering, sex
expression, etc.
v) These are mobile. They are produced at one site and show
their activities at other sites.
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Igneous & Sedimentary Rocks
Igneous Rocks:
i) Igneous rocks are formed when magma (or molten rocks) has
cooled down and solidified.
ii) Igneous rocks are commonly found inside the Earth‘s
crust or mantle,
iii) Igneous rocks can be an important source of minerals,
iv) Examples of Igneous rocks include granite and basalt.
Sedimentary Rocks:
i) Sedimentary rocks are formed by the accumulation of other
eroded substances,
ii) Sedimentary rocks are usually found in water bodies
(sea, oceans etc.).
iii) Sedimentary rocks, or their bedding structure, are
mostly used in civil engineering; for the
construction of housing, roads, tunnels, canals etc.
iv) Examples of Sedimentary rocks include shale, limestone
and sandstone.
OR
What is the difference between Igneous Rocks and Sedimentary
Rocks?
- Igneous rocks are formed from molten liquid minerals
called magma, while sedimentary
rocks are formed from lithification (cementing, compacting
and hardening) of existing rocks.
- Igneous rocks are non-porous for water, while sedimentary
rocks are porous to the water.
That is water cannot penetrate through igneous rocks but can
through sedimentary rocks.
- Igneous rocks are having fossils very rarely, while
sedimentary rocks are rich in fossils.
- Igneous rocks are harder than sedimentary rocks.
- Tendency to react with acids is higher to sedimentary
rocks when compared to igneous
rocks.
- Igneous rocks may be light or dark coloured, while
sedimentary rocks have great colour
variety.
Producers & Consumers
Producers:
Producers are organisms that make their own food through
photosynthesis or other reactions
and are a food source for other organisms (ex. plants,
extremophile benthos communities).
Consumers:
Consumers are organisms that ingest other organisms, like
plants, in order to gain energy (ex.
herbivores, carnivores, omnivores, and detrivores).
Microcomputer & Minicomputer
Microcomputer:
i) A microcomputer is a standard desktop computer used at a
home and in business.
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ii) A microcomputer is a computer with a microprocessor as
its CPU.
iii) They are cheap, compact and can be easily accommodated
on a study table.
iv) Microcomputer is a single-user computer.
v) The two most common types of storage devices used with
microcomputers are tapes and
disks.
vi) Microcomputer is not powerful or as fast as
minicomputer.
-vii) Examples are- Modern computers like desktop, laptop
etc.
Minicomputer:
i) Minicomputers are mid-sized computer used in
universities, research labs and small
corporations.
ii) Minicomputers are faster than microcomputers.
iii) They are expensive and larger than microcomputer.
iv) Minicomputer is a multi-user computer.
v) For secondary storage, most minicomputers use magnetic
disks or tapes.
vi) Minicomputer is powerful than microcomputer but not as
super computer and mainframe
computer.
vii) Examples are- IBM 9375, Motorola 68040
etc
Mainframe & Super Computers
Mainframe Computers:
i) The largest computers called mainframe computers are the
oldest category of computer
system.
ii) They are capable of great processing speed and data
storage.
iii) These are always kept in air-cooled rooms.
iv) They are mainly used in banks, airlines and industrial
companies.
Super Computers:
i) The super computers are fastest of all computers.
ii) It was invented by two brothers Gregory and David in New York .
iii) These computers have high capacity to work.
iv) These also require air-conditioned rooms.
v) The super computers are mainly used in a) Automotive
engineering b) Modelling nuclear
explosion c) Aeroplane designing d) Oil exploration e)
Weather forecasting etc.
RAM & Cache Memory
RAM
i) It stands for random access memory.
ii) It is an optical disc, where data and information is
stored permanently.
iii) RAM is the primary storage media.
iv) RAM is the primary storage device from which the system
boots.
v) RAM is stored on RAM chip.
vi) The data or information stored on it can be written on
or it can be erased.
55
Cache Memory:
i) Cache memory is a special high speed memory that the CPU
can access quickly.
ii) It is used in computers with very fast CPUs, so that
these CPUs don‘t have to wait for Data
to be delivered from RAM.
iii) The most frequently used instructions are kept in the
cache memory.
iv) This allows the CPU to run faster because it does not
have to take time to swap
instructions in and out of RAM.
Rotation & Revolution Of Earth:
Rotation Of Earth:
i) it is the movement of the earth in which the earth makes
rotation around its axis.
ii) Rotation of the earth occurs from West to East.
iii) The main effect of the rotation of the earth is the
formation of days and nights.
Revolution Of Earth
i) it is the movement of the earth, in which the earth makes
revolution around the sun.
ii) Revolution of the earth occurs in counter clockwise
direction or from right to left.
iii) The main effect of the revolution of the earth is the
change of seasons.
Dicot & Monocot Stem
Dicot Stem:
i) In dicot stem pericycle is broken.
ii) There are few vascular bundles.
iii) The vascular bundles are open.
Monocot Stem:
i) In monocot stem pericycle is not broken.
ii) there are many vascular bundles.
iii) The vascular bundles are closed.
Penumbra & Umbra
Penumbra:
The term relates to the solar and lunar eclipse. When during
its revolution, the moon comes
between the sun and the earth then solar eclipse takes
place. A shadow is created. The outer
shadow region in the eclipse is called penumbra.
Umbra:
Similarly, when the solar eclipse takes place, two regions
of shadow are created. Out of these
the dark inner shadow region is called Umbra.
Nucleus & Nucleolus
Nucleus:
i) The nucleus is the main organelle.
ii) It is mostly present in the centre of the cell.
iii) It is membrane bound.
iv) The nucleus contains DNA.
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v) It contains hereditary material in the form of chromosome
and genes and controls all the
activities of the cell.
Nucleolus:
i) The nucleolus is a sub-organelle.
ii) It is present in nucleus.
iii) It is non-membrane bound.
iv) It contains RNA.
v) It takes part in protein formation.
Lava & Magma
• Magma is the molten rock material deep inside earth‘s
crust, while the same magma, when
it finds its way to a volcano through fissures and cracks,
and comes out of the mouth of the
volcano, is referred to as lava.
• So magma is deep underground, while lava is the hot
mixture of gases and molten rocks that
comes out of the volcano.
• The most notable difference between magma and lava
pertains to their location.
Fold & Fault
Fold:
A fold is a bend in a rock layer caused by forces within the
crust of the earth. Folds usually
occur in a series and look like waves in the rock.
Fault:
Rock layers can also break, in which case a fault occurs. A
fault zone is where the sides of
broken rock have moved relative to each other.
Caustic Soda and Caustic Potash
Sodium hydroxide (NaOH) and potassium hydroxide (KOH) are
both strongly alkaline,
corrosive solids. As chemical re-agents, they are mostly
interchangeable, although some
differences exist in specific applications.
1.Chemistry in Air
o Sodium hydroxide, also known as lye or caustic soda, and
potassium hydroxide, also
known as caustic potash, are both white solids. They are
hygroscopic, meaning they will
absorb water from the air.
Sodium hydroxide will form sodium carbonate (Na₂CO₃,
washing soda) by absorption of
carbon dioxide (CO₂):
2 NaOH + CO₂ ' Na₂CO₃ + H₂O
Potassium hydroxide, however, will form potassium
bicarbonate (KHCO₃):
KOH + CO₂ ' KHCO₃
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2. Solubility
o Sodium and potassium hydroxide are strong bases. At room
temperature, they exhibit
almost identical solubilities in water - 111 grams of sodium
hydroxide will dissolve in 100
millilitres of water vs. 110 grams of potassium hydroxide.
Applications
o Both hydroxides can be used in the saponification of fats
to form soap. Soaps prepared
from potassium hydroxide tend to exhibit greater solubility
and are commonly referred to as
"soft" soaps.
Manufacture
o Sodium and potassium hydroxides are prepared commercially
by electrolysis of sodium
chloride (NaCl, table salt) or potassium chloride (KCl):
2 NaCl + H₂O ' H₂ + Cl₂ + NaOH
2 KCl + H₂O ' H₂ + Cl₂ + KOH
Differences
o In many applications, potassium and sodium hydroxide can
be freely interchanged. The
primary difference between them is cost. In ton quantities,
potassium hydroxide is about three
times more expensive than sodium hydroxide.
SEM & TEM
SEM:
SEM involves shooting an electron beam at a specimen and
observing the reactions on the
specimen surface. When the electron hits a molecule on the
surface, its energy is absorbed by
the molecule, which in turn emits a lower amount of energy.
This energy can be in the form
of a secondary, less energetic electron, a photon of light,
or x-rays. Differentiation between
these emissions is used to produce image contrast. However,
in order to produce a coherent
image, the sample must often be prepared with a conductive
coating or by embedding a resin
for many biological samples.
TEM:
TEM acts much like a typical bright field microscope in the
sense that it sends electrons
through a specimen. As it propagates through the specimen,
some of the electrons are
scattered and some are transmitted. The transmitted
electrons is passed through an objective
lens and then projected onto a scintillating material which
can then be recorded
photographically. This requires samples to be prepared in
very thin slices in order to allow
transmission of the electrons through transparent sections.
OR
A SEM (scanning electron microscope) images using the
electrons reflected from a specimen.
A TEM (transmission electron microscope) images using the
electrons that pass through it.
The image from an SEM thus looks somewhat like a normal
photo (we're used to imaging
using the light reflected from objects). However, a TEM
image takes a bit more interpretation
58
as we're not used to seeing images of light that's passed
through things - think of silhouettes
or slide projectors.
Periscope & Pyrometer:
Periscope:
Instrument used by submarines to see above the surface of
the sea.
Pyrometer:
Instrument used for measuring high temperatures.
Cell & Battery
Cell:
A cell is a DC voltage source in which chemical energy is
converted into electricity.
It is a device which produces electricity through the use of
acid and other chemicals. It is
assembly of many cells.
Perimeter & Altimeter
Perimeter:
A perimeter is a path that surrounds an area. The word comes
from the Greek peri (around)
and meter (measure). The term may be used either for the
path or its length - it can be thought
of as the length of the outline of a shape. The perimeter of
a circular area is called
circumference.
Altimeter:
An altimeter is an instrument used to measure the altitude
of an object above a fixed level.
The measurement of altitude is called altimetry, which is
related to the term bathymetry, the
measurement of depth underwater.
Pelage & Plumage
Pelage:
It is a growth of hair/fur/wool covering the skin of
animals.
Plumage:
Plumages are feathers covering the body of birds.
Smog & Smoke
Smog
Smog is formed by the interaction of pollutants present in
the air in presence of sun light
(photochemical smog), it usually restricts visibility and is
hazardous to health.
Smoke:
Smoke is the thin fine particles usually result from the
combustion.
59
Radiotherapy & Chemotherapy
1. Radiation targets only the cancer cells. However,
chemotherapy is administered through
the blood and therefore, affects both cancerous and
non-cancerous cells
2. Though they can be used for any sort of cancer, radiation
mainly targets solid tumours like
those of the cervix, spine and skin.
3. Chemotherapy treats cancers through medicines, while
radiation deals with cancer cells
through rays
4. Radiation results in additional side effects like
internal inflammation, especially in the
stomach and the intestine.
Springtides & Neap tides
Springtide:
i) Spring Tides When the moon is full or new, the
gravitational pull of the moon and sun are
combined.
ii) At these times, the high tides are very high and the low
tides are very low. This is known
as a spring high tide.
iii) Spring tides are especially strong tides (they do not
have anything to do with the season
spring).
iv) They occur when the Earth, the Sun, and the Moon are in
a line. The gravitational forces
of the Moon and the Sun both contribute to the tides.
v) Spring tides occur during the full moon and the new moon.
Neap tides:
i) Neap Tides During the moon's quarter phases the sun and
moon work at right angles,
causing the bulges to cancel each other.
ii) The result is a smaller difference between high and low
tides and is known as a neap tide.
iii) Neap tides are especially weak tides.
iv) They occur when the gravitational forces of the Moon and
the Sun are perpendicular to
one another (with respect to the Earth).
v) Neap tides occur during quarter moon.
Vertebrates & Invertebrates
• Vertebrates have a backbone with a spinal cord, whereas
invertebrates do not.
• The diversity is exceptionally high among the
invertebrates compared to vertebrates.
60
• Vertebrates are always bilaterally symmetrical, while
invertebrates could show either
bilateral or radial symmetry.
• Vertebrates are usually large-bodied and move fast compared
to invertebrates.
• Vertebrates have a closed blood system, a well-developed
brain, either gills or lungs for
respiration, and a complex and sophisticated nervous system,
whereas those are primitive in
invertebrates. Therefore, it concerns that vertebrates have
many specializations to extract the
best out of the environment compared to invertebrates.
Fluorescent & Neon Light
A neon light is the sort of light you see used in
advertising signs. These signs are made of
long, narrow glass tubes, and these tubes are often bent
into all sorts of shapes. The tube of a
neon light can spell out a word, for example. These tubes
emit light in different colours.
A fluorescent light, on the other hand, is most often a
long, straight tube that produces white
light. You see fluorescent lights in offices, stores and
some home fixtures.
The idea behind a neon light is simple. Inside the glass
tube there is a gas like neon, argon or
krypton at low pressure. At both ends of the tube there are
metal electrodes. When you apply
a high voltage to the electrodes, the neon gas ionizes, and
electrons flow through the gas.
These electrons excite the neon atoms and cause them to emit
light that we can see. Neon
emits red light when energized in this way. Other gases emit
other colours.
A fluorescent light works on a similar idea but it has an
extra step. Inside a fluorescent light
is low-pressure mercury vapour. When ionized, mercury vapour
emits ultraviolet light.
Human eyes are not sensitive to ultraviolet light (although
human skin is -- see How
Sunburns and Sun Tans Work!). Therefore, the inside of a
fluorescent light is coated with a
phosphor. A phosphor is a substance that can accept energy
in one form (for example, energy
from a high-speed electron as in a TV tube -- see How
Television Works) and emit the
energy in the form of visible light. In a fluorescent lamp,
the phosphor accepts the energy of
ultraviolet photons and emits visible photons.
The light we see from a fluorescent tube is the light given
off by the phosphor that coats the
inside of the tube (the phosphor fluoresces when energized,
hence the name). The light of a
neon tube is the colored light that the neon atoms give off
directly.
Telemeter:
A telemeter is a device used to remotely measure a quantity.
Telemeters are generally the
physical devices used in telemetry. Electronic devices are
widely used in telemetry and can
be wireless or hard-wired, analogue or digital. Other
technologies are possible, however, such
as mechanical, hydraulic and optical.
Multimeter:
A multimeter or a multi-tester, also known as a VOM
(Volt-Ohm meter), is an electronic
measuring instrument that combines several measurement
functions in one unit. A typical
multimeter may include features such as the ability to
measure voltage, current and
resistance. Multimeters may use analogue or digital
circuits—analogue multimeters (AMM)
and digital multimeters (often abbreviated DMM or DVOM.)
Analog instruments are usually
61
based on a micro-ammeter whose pointer moves over a scale
calibrated for all the different
measurements that can be made; digital instruments usually
display digits, but may display a
bar of a length proportional to the quantity being measured.
A multimeter can be a hand-held device useful for basic
fault finding and field service work
or a bench instrument which can measure to a very high
degree of accuracy. They can be
used to troubleshoot electrical problems in a wide array of
industrial and household devices
such as electronic equipment, motor controls, domestic
appliances, power supplies, and
wiring systems.
Periscope and Microscope
Periscope:
A periscope is an instrument for observation from a concealed
position. In its simplest form it
consists of a tube with mirrors at each end set parallel to
each other at a 45-degree angle. This
form of periscope, with the addition of two simple lenses,
served for observation purposes in
the trenches during World War I. Military personnel also use
periscopes in some gun turrets
and in armoured vehicles.
More complex periscopes, using prisms instead of mirrors,
and providing magnification,
operate on submarines. The overall design of the classical
submarine periscope is very
simple: two telescopes pointed into each other. If the two
telescopes have different individual
magnification, the difference between them causes an overall
magnification or reduction.
Microscope:
A microscope (from the Greek: μικρός, mikrós,
"small" and σκοπεῖν, skopeîn, "to look" or
"see") is an instrument used to see objects that
are too small for the naked eye. The science of
investigating small objects using such an instrument is
called microscopy. Microscopic
means invisible to the eye unless aided by a microscope.
There are many types of microscopes, the most common and
first to be invented is the optical
microscope which uses light to image the sample. Other major
types of microscopes are the
electron microscope (both the transmission electron
microscope and the scanning electron
microscope) and the various types of scanning probe
microscope.
Nucleon and Photon
Nucleon:
A nucleon is a collective name for two particles: the
neutron and the proton. These are the
two constituents of the atomic nucleus. Until the 1960s, the
nucleons were thought to be
elementary particles. Now they are known to be composite
particles, each made of three
quarks bound together by the so-called strong interaction.
The interaction between two or more nucleons is called
inter-nucleon interactions or nuclear
force, which is also ultimately caused by the strong
interaction. (Before the discovery of
quarks, the term "strong interaction" referred to
just inter-nucleon interactions.)
Photon:
A photon is an elementary particle, the quantum of the
electromagnetic interaction and the
basic unit of light and all other forms of electromagnetic.
It is also the force carrier for the
electromagnetic force. The effects of this force are easily
observable at both the microscopic
62
and macroscopic level, because the photon has no rest mass;
this allows for interactions at
long distances. Like all elementary particles, photons are
currently best explained by quantum
mechanics and will exhibit wave–particle duality, exhibiting
properties of both waves and
particles. For example, a single photon may be refracted by
a lens or exhibit wave
interference with itself, but also act as a particle giving
a definite result when quantitative
momentum (quantized angular momentum) is measured.
Cusec and Comet
Cusec;
Cusec is a measure of flow rate and is informal shorthand
for cubic feet per second (28.317
litres per second).
Comet:
A comet is an icy small Solar System body that, when close
enough to the Sun, displays a
visible coma (a thin, fuzzy, temporary atmosphere) and
sometimes also a tail. These
phenomena are both due to the effects of solar radiation and
the solar wind upon the nucleus
of the comet. Comet nuclei range from a few hundred meters
to tens of kilometres across and
are composed of loose collections of ice, dust, and small
rocky particles. Comets have been
observed since ancient times and have traditionally been
considered bad omens.
Telescope and Microscope are two scientific instruments that
serve their purposes differently.
One of the main differences between a telescope and a
microscope is that a telescope is used
to view things that are far whereas a microscope is used to
view things that are very near.
It is indeed true both the instruments are used to watch the
minute details of the objects or
things more clearly. Another important difference between
telescope and microscope is that
the focal length or the distance from the focal point to the
lens is different in these two
scientific instruments.
As a result of this the focal point in the case of a
telescope may be at a far off place. On the
other hand the focal point in the case of a microscope is just
a fraction of an inch off.
The difference in the diameter of the lens used in the two
instruments also matter a lot when
it comes to the difference between them. The lens diameter
or the aperture is much larger in a
telescope. This is to ensure that the aperture allows tiny
amount of natural light at the focal
point.
On the other hand only artificial illumination is used in a
microscope. The artificial
illumination is made to fall at the focal point in a
microscope. It is interesting to note that a
telescope and a microscope differ from each other in terms
of the curvature of the lens.
A microscope is used to look into smaller details like the
structure of the cells and the
unicellular organism. On the other hand larger objects that
are very far off are the targets of a
telescope. In short it can be said that a telescope is used
to look into space. Magnification is
the keyword in both the scientific instruments.
63
Antibiotics and Vaccines
1) Vaccine kills virus while antibiotics kill bacteria.
2) Vaccine is taken once and has permanent effect whereas
antibiotics work during the time
of disease.
3) Antibiotics are available in different forms like
tablets, capsules, drops or ointments.
Vaccines can be given orally or through injection.
4) Vaccines are preventive method that is taken before
getting infected. Antibiotics are taken
after getting infected.
OR
- Vaccines act against most microorganism, whereas
antibiotics act against bacteria.
- Vaccines are provided before the manifestation of the
infection, but antibiotics are given
mostly after.
- Vaccines usually have a specific single type of microbe,
whereas antibiotics would act
against a multitude of species.
- Vaccines enhance the natural immunity, and antibiotics
cause destruction of the
biochemistry of the organism.
- Vaccines are highly effective against organism, but there
may be resistance to antibiotics
needing the development of newer antibiotics.
- Both have equally lethal complications, but vaccines carry
a lesser range of complications
related to antibiotics.
Myopia:
Myopia (short sightedness) is an eye disease in which the
patient cannot see the distant
objects clearly. This disease can be corrected by using
convex lenses in glasses.
Hyperopia:
Hyperopia (long sightedness) is defect of vision in which a
person cannot see the clearly
objects lying close to him. The disease can be corrected by
using convex lenses in glasses.
Periscope & Perimeter
Periscope:
Instrument used by submarines to see above the surface of
the sea.
Perimeter:
A perimeter is a path that surrounds an area. The word comes
from the Greek peri (around)
and meter (measure). The term may be used either for the
path or its length - it can be thought
of as the length of the outline of a shape. The perimeter of
a circular area is called
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circumference.
X-rays & Gamma Rays
1. Gamma rays cause more harm to human body than the X-
rays.
2. Gamma rays have shorter wavelengths than the X-rays.
3. X rays are emitted by the electrons outside the nucleus,
and gamma rays are emitted by the
excited nucleus itself.
4. X rays are used in hospitals for taking X-rays but gamma
rays are not.
Hydrometer & Hygrometer
Hydrometer
Hydrometer is an instrument used to measure the specific
gravity of liquids. It should be
noted that specific gravity is the ration of the density of
the liquids to density of water.
Hygrometer:
A hygrometer is an instrument used to measure relative
humidity. A simple form of
hygrometer consists of two thermometers, one of which has a
dry bulb and the other, a wet
bulb.
Perimeter & Telemeter
Perimeter:
A perimeter is a path that surrounds an area. The word comes
from the Greek peri (around)
and meter (measure). The term may be used either for the
path or its length - it can be thought
of as the length of the outline of a shape. The perimeter of
a circular area is called
circumference.
Telemeter:
A telemeter is a device used to remotely measure a quantity.
Telemeters are generally the
physical devices used in telemetry. Electronic devices are
widely used in telemetry and can
be wireless or hard-wired, analogue or digital. Other
technologies are possible, however, such
as mechanical, hydraulic and optical.
Isotope & Isomer
Isotope:
Isotopes are different types of atoms of same element whose
atoms of same element whose
atomic number is same but atomic mass is different. Isotopes
have similar chemical
properties but different physical properties.
Isomers:
Isomers are compounds with the same molecular formula but
different structural formula.
Isomers do not necessarily share similar properties unless
they have same functional groups.
65
OR
Isotopes and Isomers
An isotope refers strictly to pure elements. Atoms of the
same element that have different
numbers of neutrons in their nuclei are called isotopes. For
instance, hydrogen-1 (1H) and
hydrogen-2 (2H or deuterium) are isotopes of each
other.
An isomer refers strictly to molecules. Two molecules that
have the same composition (i.e.,
the same molecular formula) but are different in the
connectivity, shape or orientation, are
called isomers. For instance, n-propanol (1-propanol) and
isopropanol (2-propanol or rubbing
alcohol) are isomers of each other. Ethanol is not an isomer
of propanol, however, because
they have different formulas.
Flying Mammal & Bird
Flying Mammals:
i. Mammals are the class of animals which give birth to live
offspring and feed their young
ones on milk from their breast.
ii.Flying mamma is the type of animal which belongs to
mammalian group with additional
quality of flying.
iii.Bats are representative animals of this group.
iii.Bats have many unusual characteristics.
v.They cannot walk very well because of skin that reaches
over its front and back legs.
vi. It flies at night and stays in caves and other dark
places during the day.
vii.Hanging upside down by the claws of its back legs, it
looks like flying mice.
Birds:
i. Birds are winged, bipedal, endothermic warm-blooded, egg
laying vertebrate animals.
ii.There are around 10,000 living species across the world.
iii.All birds have fore-limbs modified as wings and most can
fly with few exceptions like
ratites, penguins and number of various island species.
Difference between Bats and Birds
The variation between bats and birds is their structure and
class. Bats came from the
Chiroptera and Aves family. Bats are webbed structured
flying animals while birds are
feathered winged animals. Bats are mammals, so they don‘t
lay eggs, compared to birds that
are known as egg-laying animals. When flying, bats don‘t
flap their forelimbs completely
66
compared to birds. Generally, bats have teeth which help
them when eating while birds have
beaks in picking up food and eating them. Bats are nocturnal
animals; they hunt and go
around their business at night and sleep during the day
while birds work and hunt for food
during daytime and sleep at night.
Typhoons & Tornado
• Hurricane (also called typhoons) is a result of tropical
disturbance on a water body, while a
tornado is always formed on land.
• A tropical storm is labelled a hurricane if it takes place
between Atlantic and Pacific Ocean ,
but the same storm is called a cyclone if it takes place in Indian Ocean .
• Though both have eyes or centre, the centre of a tornado
can be huge, extending up to 20
miles in diameter, whereas the eye of a tornado is very
small being only a few feet in
diameter
• Hurricanes occur in the months of June to November,
whereas Tornados occur in the
months of April to June
• Tornados last for a few minutes or hours, whereas
hurricanes can have a very long duration
lasting for 2-3 weeks.
• Thunderstorms are effects of hurricanes, whereas they are
the cause of a tornado
• Hurricanes can cause floods and tsunamis, whereas tornados
spread epidemics and also
contaminate water sources.
OR
A tornado is a violently rotating column of air extending
from the base of a thunderstorm to
the ground. In weather terms tornadoes are small, 50 yards
wide on average and rarely
exceeding a mile wide, though on rare occasions tornadoes up
to 2.5 miles wide have
occurred. Tornadoes are also short lived, lasting 10 minutes
on average, though a few have
lasted for over 3 hours. Tornadoes form from interactions of
air currents in a thunderstorm.
Hurricanes and typhoons are essentially the same thing, only
a hurricane is in the Atlantic
ocean or north-eastern Pacific ocean while a typhoon is in
the north western Pacific ocean .
Both are tropical cyclones with winds of at least 74 mph. In
addition to having strong winds
these storms bring heavy rain and flooding. The average
hurricane/ typhoon is about 300
miles wide and forms over the course of several days. Unlike
tornadoes, which are generally
as land-based event These systems develop from disorganized
clusters of thunderstorms that
feed of the moisture from warm ocean water, organize, and
intensify.
Microscope & Telescope
Telescope and Microscope are two scientific instruments that
serve their purposes differently.
One of the main differences between a telescope and a
microscope is that a telescope is used
to view things that are far whereas a microscope is used to
view things that are very near.
67
It is indeed true both the instruments are used to watch the
minute details of the objects or
things more clearly. Another important difference between
telescope and microscope is that
the focal length or the distance from the focal point to the
lens is different in these two
scientific instruments.
As a result of this the focal point in the case of a
telescope may be at a far off place. On the
other hand the focal point in the case of a microscope is
just a fraction of an inch off.
The difference in the diameter of the lens used in the two
instruments also matter a lot when
it comes to the difference between them. The lens diameter
or the aperture is much larger in a
telescope. This is to ensure that the aperture allows tiny
amount of natural light at the focal
point.
On the other hand only artificial illumination is used in a
microscope. The artificial
illumination is made to fall at the focal point in a
microscope. It is interesting to note that a
telescope and a microscope differ from each other in terms
of the curvature of the lens.
A microscope is used to look into smaller details like the
structure of the cells and the
unicellular organism. On the other hand larger objects that
are very far off are the targets of a
telescope. In short it can be said that a telescope is used
to look into space. Magnification is
the keyword in both the scientific instruments.
Ultrasonics & Infrasonic:
Ultrasonics:
The study of sound aves with high frequencies beyond the
upper limit of human hearing or 20
thousand Hz. This technique is employed to locate a tumour,
to scan a pregnant woman‘s
abdomen in order to produce a picture of foetus or to treat
certain neurotically disorders.
Infrasonic:
These are the sound waves which have the frequencies lowest
than the lowest limits of
human hearing or 20 Hz.
OR
The sounds having frequency more than 20,000 hertz (Hz) are
called ultrasonic or ultrasound
and the sounds having frequency less than 20 Hz are called
infrasonic or infrasound. Both of
these sounds cannot be heard by human beings. The audible
range for of hearing by human
beings is 20 Hz to 20000 Hz.
Antibodies:
Protein synthesized in the blood in response to the entry of
foreign substances or organisms into the
body. When the body get infected through virus or bacteria,
specific antibody is produced which
fights the disease.
Antibiotics:
These are substances which can stop the growth or destroy
the bacteria or other microorganisms. The
antibiotics are used to eliminate fatal diseases such as
typhoid, plague and cholera etc.
OR
68
Antibodies
l They are what your body produces in response to the
presence of antigens (bacterial or viral surface
structures)
l They merely assist your white blood cells in identifying
l They also destroy and invade the unidentified
microorganisms.
Antibiotics
l They are chemicals that work to destroy invading bacteria
(usually by disrupting the outer cell wall
and making it "leak" or by messing up the
bacteria's metabolic processes. They are not produced by
the body)
l Antibiotics can be antibacterial or antiviral.
Antibacterial will only destroy bacteria and antiviral
will only destroy viruses. There are not many antibiotics
for viruses. Also a virus is not a eukaryote.
Antigen & Vaccine
Antigen:
A substance or organism that induces the production of an
antibody. The antigen reacts with
antibody. The antigen tissue proteins can cause problems in
the transplant of organs by rejecting the
introduction of new organ in the body.
An antigen is a foreign molecule that, when introduced into
the body, triggers the production of an
antibody by the immune system. The immune system will then
kill or neutralize the antigen that is
recognized as a foreign and potentially harmful invader.
These invaders can be molecules such as
pollen or cells such as bacteria. The term originally came
from antibody generator[1][2] and was a
molecule that binds specifically to an antibody, but the
term now also refers to any molecule or
molecular fragment that can be bound by a major
histocompatibility complex (MHC) and presented
to a T-cell receptor. "Self" antigens are usually
tolerated by the immune system; whereas "Non-self"
antigens are identified as invaders and attacked by the
immune system. self-antigens.
Vaccine:
The agent which is used to give immunity against various
diseases. A vaccine consists of modified
disease organisms such as live weakened viruses or dead that
can induce the production of antibodies
within the blood.
A vaccine is a biological preparation that improves immunity
to a particular disease. A vaccine
typically contains an agent that resembles a disease-causing
microorganism, and is often made from
weakened or killed forms of the microbe or its toxins. The
agent stimulates the body's immune
system to recognize the agent as foreign, destroy it, and
"remember" it, so that the immune system
can more easily recognize and destroy any of these
microorganisms that it later encounters.
Vaccines can be prophylactic (example: to prevent or
ameliorate the effects of a future infection by
any natural or "wild" pathogen), or therapeutic
(e.g. vaccines against cancer are also being
investigated; see cancer vaccine).
69
8. Short/Long Notes
Solar
System
The solar system is the family of the sun, planets revolving
around it, the satellites of the
planets and the asteroids or meteoroids and comets etc.
• There are eight planets in the solar system.
• Starting from the sun there are Mercury, Venus, Earth,
Mars, Jupiter, Saturn, Uranus and
• All the planets revolve around the sun in their orbits.
• Meteorite analysis shows that the age of solar system is
about 4530 million years.
• The sun is not the largest star of the Milky Way; rather
it is an average sized star.
• It is not at the centre of the galaxy but shifted towards
a side.
• The diameter of the sun is 1, 392, 140 km and its mass is
2 * 1027 tonnes.
• The outermost layer of the sun is called photosphere, has
an average temperature of 5570
0C.
• The photosphere rotates at a rate of 25.38 days per turn.
• At the centre of the sun hydrogen is undergoing nuclear
fusion reaction which provides
energy for the heat and light so sun.
• The planets of the solar system as well as the moons get
light and sometimes heat from the
sun.
• The four inner planets of the solar system are called
terrestrial plants because of their rocky
nature.
• The outer planets are called gaseous planets because they
don‘t have solid surface and are
composed of gases.
Planets And Their Characteristics:
1. Mercury
• Its distance from Sun is 58 million kms.
• Its revolution period is 88 days.
• Its rotation period is 58 days, 15 hours and 30 minutes.
• It has no moon.
• It is the nearest planet to the sun.
70
• It is also the smallest planet of the solar system.
• It is the fastest planet.
• Its radius is 2,433 kms and diameter is 4,878 kms.
• It is covered with holes called Craters.
• It has no atmosphere.
• The temperature on mercury vary between 420 0C (7900F) in
the day and -180 0C (-2900F) at
nights.
2. Venus
Apart from the moon, Venus is the brightest object in the
sky. Venus can be seen with naked eye
in the morning or in the evening. Following are the main
characteristics of the Venus.
• Its distance from the Sun is 108 million kms.
• Its revolution period is 224.7/225 days.
• Its rotation period is 243 days and 14 hours (longest day)
• It has no moon.
• It is the nearest neighbour of the earth in the solar
system.
• It is the brightest planet.
• It is also the hottest planet.
• Its diameter is 12,102 kms.
• It is wrapped in thick clouds of CO2 gas.
• It rotates from east to west as opposite to most other
planets.
3. Earth
The earth is the largest and the densest of the four
terrestrial planets. It is the most wonderful
planet of the solar system. Following are the features of
the Earth.
• Its distance from the Sun is 150 million kms.
• Its revolution period is 365 ¼ days.
• Its rotation period is 23 hours, 56 minutes, 40 seconds.
• It has one moon.
• It is the densest planet.
• It is also the watery and bios planet.
• Its diameter is 12756 km (7927 miles equatorial and 7900
miles polar diameter)
• It has atmosphere which contains 78% Nitrogen, and 21% Oxygen.
• Its two-thirds surface is covered with oceans.
• The earth‘s surface is rich in Oxygen, Silicon, Aluminium,
Iron, Calcium, Sodium etc.
4. Mars
• Distance form sun 228 million kms.
• Revolution period 687 days.
• Rotation period 24 h, 37 min and 22 sec.
• It has two moons Phobos and Deimos.
• Its diameter is 6794 kms.
• Mars is covered with red dust.
• It has an atmosphere composed almost entirely of CO2.
• Its average temperature is -53 0C.
71
5. Jupiter
• Its distance from sun is 778 million kms.
• Revolution period 12 years.
• Rotation period 9h, 50min, and 30 sec. (smallest day)
• It has 63 moons.
• It is the largest planet of the solar system.
• It has the largest number of satellites.
• Its diameter is 1, 24,800 kms.
• Its diameter is eleven times greater than the earth‘s
diameter.
• It has a dense, cloudy atmosphere of hydrogen and helium.
• It has a rock-iron-ice core about 15, 000 km (9,000 miles)
thick.
• Jupiter radiates 67% more heat than it receives from the
sun. this is mainly due to dissipation of
the primordial heat of the planet.
6. Saturn
In 1610, Galileo became the first person to look at Saturn
through telescope.
• Distance from Sun 1427 million kms.
• Revolution period 30 years.
• Rotation period 10h, 14 mins.
• It has 62 moons.
• The largest moon of Saturn is the Titan and it is the
second-largest moon in the solar system.
Titan is larger than the planet Mercury.
• It is the second largest planet.
• It has a magnificent system of rings.
• Its diameter is 1, 20, 000 km.
7. Uranus
When sky is very dark and very clear Uranus can be seen with
the naked eyes. The planet was
discovered by William Herschel in March 1787.
• Its distance from Sun is 2869.9 million kms.
• Revolution period is 84 years.
• Rotation period is 16h, and 10 mins.
• It has 27 moons.
• Titania is the largest moon of Uranus.
• It has an atmosphere which is dominated by hydrogen and
helium.
• Its diameter is 52, 400 km.
8. Neptune
• Distance from Sun 4496, 6 million kms.
• Revolution period 165 years (largest year)
• Rotation period 18 hours.
72
• Neptune has 13 moons that
we know of. The largest moon is Triton.
• It is the coldest planet.
• It is the slowest to move around the sun.
• Its diameter is 49,100 kms.
• It is known as the twin of Uranus due to their similarity
of size, mass and composition.
Short Note (Solar System)
Lunar Eclipse:
The partial or complete obscuration of light of moon for an
observer on the earth is called lunar
eclipse.
Lunar eclipse takes place when the earth comes in position
between the sun and the moon. In this
way, the shadow of the earth is cast on the moon and the
moon does not get sunlight in this
position.
Lunar eclipse occurs only when there is full moon. But this
does not happen on every full moon
because of inclination of the axis of earth to its orbit.
Solar Eclipse:
Solar eclipse occurs when the moon comes in between the Sun
and the earth and its shadow is
cast across the face of the earth.
The solar eclipse occurs when the moon moves to a position
between the Sun and the Earth.
During this process it throws shadow on the earth. This
shadow is categorized in umbral and
penumbra. The people who are in the umbral region are unable
to see the sun at all. This
condition is known as the total eclipse of the sun. While
the people in penumbra region can see
the sun partly this is known as the partial eclipse of the
sun.
This happens with the new moon when the moon is in
conjunction with the sun. this does not
happen at every new moon because of the inclination of the
orbit of the moon to the orbit of earth
around the sun.
Asteroids:
Asteroids are also known as planetoids. These are small,
irregularly shaped rocky objects which
orbit the Sun between the orbits of Mars and Jupiter.
Asteroids are also known as the minor
planets.
Basically the word Asteroid means ―Starlike‖. Ceres asteroid
was the first to be discovered.
Meteorites:
Meteorites are small chunks of iron and rock thought to be
resulted from collisions between
asteroids. They also may be formed when comets disintegrate
into fragments. Meteorites enter the
earth‘s atmosphere and become a meteor. A meteor is a
―falling star‖ that is usually seen in the
sky at night. A meteor will burn up from frictional heating
as it enters the atmosphere. Most of
the meteors burn up before they reach the earth. If they do
not reach the ground they become
meteorites. Meteorites can be seen at a distance of 70 miles
from the earth. Meteorites are heavy
objects which weigh about 60 tons.
Comets:
Comets are those bodies which revolve round the sun. they
are mainly composed of ice and dust.
Most comets have three parts which are as under.
i) A solid centre.
ii) A head or round coma, that surrounds the centre and
consists of dust particles mixed with
73
frozen water, frozen methane and frozen water, frozen
methane and frozen ammonia.
iii) A long tail of dust and gases that escape from the
head. Most comets stay near the solar
system.
Other characteristics of comets are as under:
• Comet is usually about 10 km or 6 miles across.
• Comets are usually made up of ice and dust.
• Millions of comets are present in the solar system.
• Halley‘s comet is the famous example.
• Comets usually move around the sun in the elliptical
orbits.
Light Year:
The distance travelled by light at speed of 186,000 miles
per seconds in one year is known as a
light year. One light year is approximately 9461,000 million
kilometres or 5875000 miles. Light
year is also used to measure the distance between the
galaxies.
Astronomical Unit:
The distance between the Sun and the Earth is called as
Astronomical Unit. This unit is also used
in the measurement of distances between the heavenly bodies
within the solar system. The earth
is one A.U away from the Sun and the Pluto is 39 A.U away
from the Earth.
Black hole:
Black Hole is a hypothetical region in space which has a big
gravitational pull for which no
matter or radiation can escape from it. Even it is believed
that light cannot escape from it. Black
Hole usually likes at the centre of galaxy.
Super Nova:
A Super Nova is an exploding star. At the end of its phase
as a Red Giant, a heavy star explodes
as a Supernova shining briefly as brightly as a thousand
million stars. Recent Supernova was
observed on the night of Feb 23, 1987. This occurred in
Large Magellanic Cloud.
Nebula:
Nebula is derived from a Greek word which means ―Cloud‖. In
the sky there are clouds like
objects, which are classified as Nebulae. There are both luminous
diffuse nebulae and dark
obscuring nebulae over the Milky Way. They are made up of
dust and gases.
Polar Regions with a tremulous motion and giving forth
streams of eight Aurora .
It is generally
believed that the aurora is actually caused by radiation
from the Sun-spots.
Solar Wind:
Solar wind is the stream of electrically charged particles
especially protons and electrons, which
are emitted by the Sun, predominantly during solar flares
and sunspots activity. Some of these
particles become trapped in the Earth‘s magnetic field
forming the outer Van Allen radiation belt,
but some penetrate into the upper atmosphere where they
congregate in narrow zones in the
region of the Earth‘s magnetic poles producing aurora
displays.
Cosmic Rays:
Cosmic Rays are charged particles moving as fast as the
speed of light. Most of the particles are
protons, while some are alpha particles and electrons. They
travel throughout our galaxy,
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including the solar system and some strike the earth‘s
atmosphere. They can be detected by
instruments on the Earth. Nobody knows how cosmic rays are
formed. Some of them are formed
by exploding stars or supernova and some come from outside
our Galaxy.
Some Important Definitions:
Cosmology:
Cosmology is the science of the cosmos or universe.
OR
Cosmology is the branch of physical science which deals with
the Universe.
Universe:
The universe is the sum total of all that exists, or has
existed, both in space and time.
Galaxy:
A galaxy is a system of many thousands of millions of stars
together with inter-stellar gas and
dust.
OR
Galaxy is a fundamental unit of the universe. It is composed
of hundreds of thousands of stars
together with intra-stellar gas and dust.
Star:
Those heavenly bodies which are luminous and produce their
own energy by nuclear reactions
are called stars.
• Proximal Centauri second nearest after Sun to the Earth.
• Antares is one of the largest stars known.
Solar system:
A tiny system of our galaxy which consists of the /sun, a
planet and their satellites, thousands of
miniature planets called asteroids, meteoroids, comets,
interplanetary dust and plasma.
Satellite:
Those heavenly bodies which revolve round the planets are
called satellites.
Eclipse:
In astronomy, the term eclipse simply means the obscuring of
one heavenly body by another,
particularly that of the sun or a planetary satellite.
Lunar Eclipse:
A condition when the earth comes in between the sun and the
moon and throws its shadow on the
moon is called lunar eclipse.
Solar Eclipse:
A condition when the moon comes in between the sun and the
moon and throws its shadow on
the moon is called Solar Eclipse.
Astrology:
Astrology is the interpretation of the influence of planets
and stars on human lives.
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Asteroids:
Small, irregular shaped rocky objects which orbit the sun
between the orbits of Mars and Jupiter
are called Asteroids.
Meteorites:
Tiny chunk of material floating in space which can also
enter the earth‘s atmosphere and become
meteor are known as meteorites.
Comets:
The bodies mainly composed of ice and dust which revolve
round the sun are called comets.
Balanced Diet:
• ―The food which contains all essential food nutrients
which are necessary and essential for
healthy growth of the body and proper functioning of the
whole parts of body.‖
• Food is a complex mixture of chemical substances.
• It performs following useful functions when eaten and
absorbed by the body.
i) Produces energy
ii) Promote growth
iii) Repair the tissues
iv) Regulate various processes
• Nutrients are the chemical components of food capable of
performing above functions.
• Example: milk is a balanced diet although it does not
contain iron.
• Following are the major components of Balanced Diet and
their source and functions:
i) Carbohydrates
• Source: Honey, Sugarcane, Wheat, Maize, Potatoes.
• Functions: Provide energy
ii) Fats:
• Source: Butter, Cheese, Soya bean, Mustard etc.
• Functions: Provide Energy
iii) Proteins:
• Source: Meat, Eggs, Fish, Milk, Pulses etc.
• Functions: Essential for growth
iv) Vitamins:
• Source: Fruits and Vegetables.
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• Functions: Important for proper physiologic and metabolic
functions of the body.
Types:
a) Water Soluble Vitamins: B1, B2, B6, B12, C
b) Fat Soluble vitamins: A, D, E, K
v) Minerals: Minerals are those inorganic substances which
play a key role in the maintenance
and building of the body tissues. The most important
minerals of balanced diet are as under:
• Phosphorus: is necessary for bones and teeth.
• Iron: is an essential component of blood.
• Iodine: is necessary for thyroxin which is secreted from
thyroid gland.
• Calcium: is necessary for bone development.
vi) Water:
• Source: Fruits, Vegetables
• Functions: It is constituent of blood, lymph, hormones and
other secretions of the body.
Functions Of Vitamins:
1. Vitamin A
i) Role: Vitamin A plays an important role in growth and
body repair, keeps the skin smooth and
essential for vision.
ii) Deficiency: it deficiency causes ―Night Blindness‖.
iii) Source: Fortified milk, butter, eggs, cream, leafy
vegetables, carrot.
2. Vitamin B1
i) Role: it is an energy building vitamin, help in the
digestion of carbohydrates, keep the heart
and muscle stable and necessary for nerves.
ii) Deficiency: its deficiency causes Beri Beri, muscular
weakness, cramps and heart swelling.
iii) Source: Pork, cereals, legumes, nuts and seeds.
3. Vitamin B2 (Riboflavin)
i) Role: It is important in forming RBCs, protection of
mouth and mucous membrane and skin.
ii) Deficiency: its deficiency causes ―Pellagra‖
iii) Source: Milk, leafy green vegetables, cereals etc.
4. Vitamin B3 (Niacin)
i) Role: Helps in releasing energy from carbohydrates, fats
and proteins, very essential for the
DNA synthesis, used to lower elevated LDL cholesterol and
triglyceride levels in the blood,
boosts the level of HDL, the 'good' cholesterol, in the
body, essential for the proper digestion of
the food etc.
ii) Deficiency: its deficiency causes Loss of appetite,
Indigestion, Skin lesions, Mental imbalance
etc.
iii) Source: Meat, poultry, fish, cereals, vegetables,
peanuts, butter etc.
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5. Vitamin B6 (Pyridoxine)
i) Role: it is essential for the production of antibodies,
for the CNS and help in protein
metabolism in the body.
ii) Deficiency: Skin problems, Nervous system disorders,
Muscle spasms, Sleeplessness.
iii) Source: Meat, fish, poultry, vegetables, fruits etc.
6. Vitamin B12 (Cynocobalamin)
i) Role: it is important for carbohydrate and fat
metabolism, growth of child and formation of
blood.
ii) Deficiency: its deficiency causes ―anaemia‖
iii) Source: Meat, poultry, fish, seafood, eggs, milk.
7. Vitamin C (Ascorbic Acid)
i) Role: It is essential for protection of bones and for
healthy teeth and gums.
ii) Deficiency: its deficiency causes ―Scurvy‖
iii) Source: Citrus fruit, guava, pineapple, tomatoes,
spinach, turnips, strawberry.
8. Vitamin D:
i) Role: It is very important for the growth of children.
ii) Deficiency: Its deficiency causes ―Rickets‖ in children
and Osteoporosis in adults.
iii) Source: Egg yolk, liver, fish, milk.
9. Vitamin E:
i) Role: it plays an important role in wound healing,
prevention of sterility, breaking blood clots
and prevents damage of cells due to aging.
ii) Source: Leafy green vegetables, soya bean, cotton seed,
liver, egg yolk, nuts etc.
iii) Deficiency: its deficiency slows down the formation of
RBCs.
10. Vitamin K:
i) Role: essential for blood clotting.
ii) Deficiency: its deficiency causes ―Blood clotting
Disorder‖
iii) Source: Leafy green vegetables, milk, fish, liver,
alfalfa.
Minerals: Their Functions, Source and Sings Of Deficiency:
1. Calcium:
i) Role:
a) It is essential constituent of bones and teeth.
b) It is vital for metabolic process such as nerve function,
muscle contraction, and blood clotting.
ii) Source: Dairy Products
iii) Deficiency: Osteomalacia (softening of bones),
Osteoporosis, Rickets, Tetany
2. Iron:
i) Role: It is the key constituent of haemoglobin which
helps in transfer of oxygen.
ii) Source: Eggs, Green Vegetables, Fortified foods,
Cereals, White flour, Liver, Meat, Nuts,
Peas.
iii) Deficiency: Anaemia, Increased susceptibility to
infection.
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3. Magnesium:
i) Role: it is essential for healthy bones; muscles and
nervous tissues. It is needed for functioning
of approx. 90 enzymes.
ii) Source: Eggs, leafy vegetables, fish, milk and dairy
products.
iii) Deficiency: Anxiety, fatigue, insomnia, muscle problem,
nausea, premenstrual problem.
4. Phosphorus:
i) Role: it is important for healthy bone tissues.
ii) Source: Dairy products, fruits, meat, pulses, leafy
vegetables.
iii) Deficiency: Anaemia, demineralization of bones, nerve
disorder, respirator problem,
weakness, weight loss.
5. Potassium:
i) Role: it is essential for intracellular fluid,
maintenance of electrical potential of the nervous
system and functioning of muscle and nerve tissues.
ii) Source: Cereals, coffee, fresh fruits, meat, vegetables,
whole-grains, flour.
iii) Deficiency: General muscle paralysis and metabolic
disorder.
6. Sodium:
i) Role: it is necessary for the control of the volume of
extra cellular fluid in the body
maintenance of pH of the body, and electrical potentials of
the nervous system.
ii) Source: Bakery products, Table salts
iii) Deficiency: Low blood pressure, general muscle
weakness, respiratory problems.
Computer:
“The word Computer is derived from compute which means to
calculate. In simple and
technical term it is an automatic electronic calculating
machine that processes or
manipulates a given data according to a program or set of
instructions and gives a desired
output.”
Parts Of A Computer:
The computer is composed of two parts:
1) Hardware
2) Software
1) Hardware:
All physical components of computer, which can be touched,
measured, have weight and occupy
space, are collectively called computer hardware viz;
i) Keyboard
ii) Mouse
iii) Joy stick
iv) Scanners
v) Monitor
vi) Printer
vii) Central Processing unit etc.
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2) Software:
Software can be defined as a set of instructions or codes
written in a defined manner. In other
words softwares are prewritten programs, which control the
operations of computer.
OR
All programs and data stored on floppy disk, Hard disk,
CD-ROM are collectively called
softwares. Examples are;
i) DOS
ii) Window
iii) UNIX
iv) XENIX
v) Linus
vi) Java
vii) MS Office
Devices OR Components Of A Computer:
The computer is a combination of many parts, each of which
performs specific task
independently. The major devices of a computer are as under.
1) Input Devices
The input devices are those devices which send data or
information to the Central Processing
Unit. The main input devices are:
i) KEYBORD: It is used to enter text. It contains
alphabetic, numeric and other keys for entering
data.
ii) MOUSE:It is a pointing device. It controls the pointer
on the screen.
iii) MICROPHON: It is used to enter voice into the computer.
iv) SCANNER: It reads printed text and graphics and then
translates the result into digital form.
v) DIGITAL CAMERA:It is used to take photos.
vi) PC CAMERA: It is used to create movie and to take photos
on the computer.
2) OUT PUT DEVICES:
A hardware component used to display information to the user
output device.
i) MONITER: It is used to display text, graphics and video
output.
ii) PRINTER: It is used to display printed output on paper.
iii) SPEAKER:It is used to hear sound to hear sound music
and voice outputs.
3) STORAGE DEVICE:
The hardware components used to store data, instructions and
information permanently are called
storage devices. For example floppy disk drive, zip drive,
hard disk drive, CD-ROM drives etc.
4) COMMUNICATION DEVICES:
It is used to communicate and exchange data, instructions
and information with other computers.
For example Modem.
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UNITS OF CPU:
• ALU(ARTHMETIC AND LOGICAL UNIT)
ALU is a part of CPU. Actual execution of instructions takes
place in this part. All arithmetic and
logical operations are performed in ALU. It consists of two
units:
1. Arithmetic Unit
It performs basic arithmetic functions such as addition,
subtraction, division.
2. Logical Unit
It performs logical operations like comparing two data items
to find which data item is greater
than, equal to, or less than the other.
• CONTROL UNIT
It acts like a supervisor of the computer. It does not
execute program instruction by itself. It
controls and coordinates all activities of computer system.
• Memory Unit (MU)
It is responsible for storage of data and information. The
memory unit consists of two types of
memory which are RAM and ROM.
Some Important Definitions And Short Notes:
RAM:
RAM stands for random access memory. It is that part of CPU
where temporary information is
stored.
Byte:
A group of 8 bits is called a byte.
Icons:
Pictorial objects on the desktop or screen are called Icons.
Mouse:
It is an input device, normally called a ―Pointing device‖.
This device is used for pointing
anything on monitor through a blinking cursor.
Software:
A set of instructions or codes written in a defined manner
or prewritten programs which control
the operations of computer.
Control Unit:
A unit of CPU which is responsible for all automatic
operations carried out by the digital
computers is called CU. The CU directs and coordinates all
activities of a computer.
LAN:
LAN stands for local area network. It is privately owned
communication network that serves
users within a confirmed geographical area. The range is
usually within a mile-perhaps one
office, one building or a group of buildings.
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WAN:
It stands for wide area network. It is a communication
network that covers a wide geographical
area. The range is usually a state or a country. Examples
are Telenet, Uninet etc.
Modem:
Modem is abbreviation of Modulate-de-Modulate. Modulation is
a process that converts digital
signals into Analog form and Demodulation is a process that
converts Analog signals into digital
form. The device which performs modulation and demodulation
is called a MODEM. In simple
words it is a device that converts the digital signals into
Analog and then back from Analog to
digital form.
ALU:
A unit of CPU that performs arithmetic and logical
operations is called ALU.
Register:
Registers are high-speed staging areas that temporarily
store data during processing and provide
working areas for computation.
Registers are contained in control unit and arithmetic Logic
Unit. Following are the major types
of registers:
i) Address Register
ii) Instructions Register
iii) Storage Register
iv) Accumulator Register
Soft Copy:
It displays the data on screen of monitor. It can be carried
in a floppy disk. A change can be made
in a soft copy.
Hard Copy:
The data is printed on paper card etc. with the help of
printer. It cannot be carried in a floppy
disk. No change can be made in hard copy.
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Energy:
Definition Of Energy:
―Energy is an agent which is responsible to do work.‖
OR
―The capacity or ability of doing some work is known as
energy.‖
Kinds OR Types Of Energy:
i) Kinetic energy: The energy due to motion of a body is
called Kinetic Energy.
Example: i) Moving ball can break a glass window ii) A
striking hammer can drive a nail.
ii) Potential Energy: the energy which is possessed by a
body by means of its position is known
as potential energy.
iii) Mechanical Energy: Energy of an object due to its motion
or position
OR
A combination of kinetic and potential energy resulting from
the force of gravity or the
movement or release of a machine component, such as a
spring, clamp, or wheel.
iv) Chemical energy: energy in a substance that can be
released by a chemical reaction. For
example: coal, petroleum are the source of chemical energy.
v) Electrical energy: energy made available by the flow of
electric charge through a conductor.
vi) Heat energy: a form of energy that is transferred by a
difference in temperature.
vii) Solar energy: Radiant energy emitted by the sun.
viii) Hydropower energy: The energy in flowing water is
called Hydropower Energy.
ix) Nuclear energy: The energy released by a nuclear
reaction, especially by fission or fusion.
Energy Resources:
Energy resources can be divided into two categories.
1) Renewable Resources Of energy
2) Non-Renewable Resources Of energy
Renewable Resources Of Energy:
Renewable energy is energy which is generated from natural
sources i.e. sun, wind, rain, tides
and can be generated again and again as and when required.
They are available in plenty and by
far most the cleanest sources of energy available on this
planet. For e.g.: Energy that we receive
from the sun can be used to generate electricity. Similarly,
energy from wind, geothermal,
biomass from plants, tides can be used this form of energy
to another form.
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OR
The resources of energy which can be used again and again
are known as renewable resources.
These are:
i) Solar energy: Solar energy is the energy derived from the
sun through the form of solar
radiation.
ii) Wind energy: Wind power is the conversion of wind energy
into a useful form of energy,
such as using wind turbines to make electricity, wind
mills...
iii) Hydropower energy: Energy in water can be harnessed and
used. Since water is about 800
times denser than air, even a slow flowing stream of water,
or moderate sea swell, can yield
considerable amounts of energy.
iv) Tidal energy: Tidal power, also called tidal energy, is
a form of hydropower that converts the
energy of tides into useful forms of power - mainly
electricity.
v) Geothermal energy: Geothermal energy is power extracted
from heat stored under the earth‘s
crust. This power source is generally cost effective,
usually reliable, mostly sustainable, and
generally environmentally friendly.
Non-Renewable Resources Of Energy:
Renewable energy is energy which is taken from the sources
that are available on the earth in
limited quantity and will vanish fifty-sixty years from now.
Non-renewable sources are not
environmental friendly and can have serious effect on our
health. They are called non-renewable
because they can be re-generated within a short span of
time. Non-renewable sources exist in the
form of fossil fuels, natural gas, oil and coal.
OR
The resources of energy which can be used for a particular
period of time, after that they may not
be available for the use of man. These include:
i) Coal: Coal is a combustible black or brownish-black
sedimentary rock formed from fossilized
plants. Coal consists of amorphous carbon with various
organic and some inorganic compounds
and is normally occurring in rock strata in layers or veins
called coal beds.
ii) Gas: Natural gas is a combustible mixture of hydrocarbon
gases that occurs with petroleum
deposits consisting primarily of methane. It is found with
other fossil fuels and in coal beds and is
created by the decay of methanogenic organisms in marshes,
bogs, and landfills. Lower
temperatures are likely to produce more petroleum, and
higher temperatures are likely to produce
more natural gas.
iii) Oil: Petroleum, also known as crude oil, is a naturally
occurring toxic combustible liquid
primarily made up of hydrocarbons. Petroleum is the result
of partial decay of living organisms
occurring in the rock strata of certain geological
formations.
iv) Nuclear fuels: Nuclear power is produced by controlled
nuclear fission (splitting atoms). In
most cases nuclear power plants use nuclear fission
reactions to heat water, using the steam to
produce electricity. Uranium, specifically, uranium -235, is
one of the few elements easily
fissioned.
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v) Wood: Wood and wood products used as fuel, including
round wood (cord wood), limb wood,
wood chips, bark, sawdust, forest residues, charcoal, pulp
waste, and spent pulping liquor.
Non-Conventional Sources Of Energy:
Non-conventional sources of energy are those sources of
energy which are not in common use at
this time but are being considered or explored to bring to
routine use in the future. With the
exhaustion of conventional sources of energy the search for
non-conventional sources of energy
have been intensified.
Conventional sources of energy are coal, gas, oil, wood and
nuclear fuels. These sources are in
routine use nowadays.
Non-conventional sources of energy are solar energy,
geothermal energy. Wind energy, tidal
energy and ocean thermal gradient.
Solar Energy:
The energy of the sun is called solar energy. It has been
estimated that on the average 180,000
kilowatts solar energy is falling per square kilometre of
the earth. Solar energy is utilized in two
ways.
A solar furnace contains thousands of mirrors to focus the
sun rays. In this solar heater produces
heat used in industry or houses. The heaters heat up water
or air. Solar energy can also be used
indirectly. Solar cells made up of panels of semi-conductors
(usually silicon) are used which
when illuminated by sun generate electricity. These kinds of
cells have frequently been used in
space probe. They have not become popular in domestic side
due to high cost.
Wind Energy:
Energy obtained from wind by using wind mills is called wind
energy. The wind rotates
generated which produce electricity.
Previously wind mills were used for grinding grains. The
rotating wings of a wind mill can be
attached to a magnet which gives an electric current with
rotation. Low power, high cost and
uncertainties of weather had not made power generation
through wind power.
Geothermal energy:
Heat energy obtained from the hot molten metals inside the
earth crust serves as the source of
thermal energy. This type of energy is present in the form
of hot water and steam. Geothermal
electricity plants change the geothermal energy into
electricity. Hot water of springs is being used
for power generation particularly in USA , Italy ,
and Japan etc. furthermore; hot
springs are used
as geysers for heating the houses.
Nuclear Energy:
The most concentrated form of energy is in the atomic
nuclei. This energy can be released by the
processes of fission or fusion.
Fusion reactions have been producing electricity in
commercial quantities for about 30 years. In
megawatt of power to meet ur future domestic and industrial needs, we
will have to generate
electricity from nuclear plants using (Uranium U-235) and
plutonium s fuel.
Tidal Energy:
Energy which is obtained through the tidal waves of the sea
is called tidal energy. Tidal waves of
sea strike the shore constantly. These waves are used to run
electric generators which produce
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electricity. The kinetic energy of the tides is also used to
produce other forms of mechanical
work. Tidal power station traps high tides behind a barrage.
The water flows through turbines.
Greenhouse Effect:
The heating that occurs when gases such as carbon dioxide
trap heat escaping from the Earth
and radiate it back to the surface; so-called because the
gases are transparent to sunlight but
not to heat and thus act like the glass in a greenhouse.
OR
The overall warming of the earth's lower atmosphere
primarily due to carbon dioxide and
water vapour which permit the sun's rays to heat the earth,
but then restrict some heat-energy
from escaping back into space.
Greenhouse Gases:
i) Carbon dioxide CO2
ii) Methane
iii) Water Vapour
iv) Chloro Fluoro-Carbon (CFC)
v) Nitrous oxide
Mechanism OF Greenhouse Effects:
• Our Earth receives most of its energy, called radiation,
from the Sun.
• This energy is electromagnetic radiation in the form of
Visible light, with small amounts of
Infrared (IR) and Ultraviolet (UV).
• The incoming Visible solar energy has a very short
wavelength and passes right through the
atmosphere.
• The Earth's surface absorbs the solar energy and releases
it back to the atmosphere as
Infrared (IR) radiation, some of which goes right back into
space.
• But some of the IR radiation emitted by the Earth is
absorbed by greenhouse gases in the
atmosphere and sent back towards the Earth's surface.
• That warms the Earth's surface. Three main gases in our
atmosphere that contribute to the
greenhouse effect are carbon dioxide, methane, and
water.
• These gases absorb the infrared radiation emitted by the
Earth and re-radiate the energy as
heat back towards the Earth, causing a warming known as the
greenhouse effect.
• The warming due to greenhouse gases is expected to
increase as humans add more
greenhouse gases to the atmosphere.
Sources Of Greenhouse Gases:
Carbon dioxide (CO2) is a colourless gas that's a by-product
of the combustion of organic
matter. Today human activities are pumping huge amounts of
CO2 into the atmosphere,
resulting in an overall increase in carbon dioxide
concentrations.
Methane occurs naturally when organic material decomposes.
Man-made processes produce
methane in several ways:
• By extracting it from coal
• From large herds of livestock (i.e., digestive gases)
• From the bacteria in rice paddies
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• Decomposition of garbage in landfills
Importance Of Greenhouse Effect:
Following is the importance of greenhouse effect.
i) Without greenhouse effect, the Earth would not be warm
enough for humans to live.
ii) Without greenhouse gases, heat would escape back into
space and Earth‘s average
temperature would be about 600 F colder.
Global Warming:
A gradual increase in the overall temperature of the earth's
atmosphere generally attributed to the
greenhouse effect caused by increased levels of carbon
dioxide, CFCs, and other pollutants
Causes Of Global Warming:
The main causes of global warming, in order of the magnitude
of their impact, are:
1. Carbon Dioxide from:
A. Fossil Fuel
B. Deforestation
C. Failing Sinks
2. Methane from:
A. Cattle and Rice Paddies
B. the Arctic Tundra
C. Clathrates
3. Nitrogen Oxides from Farming
4. Other Gases
Effects OF Global Warming:
When it comes to global warming, harmful effects like
melting polar ice caps, weather changes,
and an increase in diseases are changing the world and will
ultimately affect your life. Below is
the list of effects that global warming is having on
environment, climate and human kind.
1. Melting of glaciers: The melting of glaciers will create
plethora of problems for human kind
and the animals living in the earth. Due to increased global
warming, the level of the sea will rise
which will lead to flooding and this will in turn create
havoc in human life. Apart from raising the
sea levels, it will also endanger several species of animals
and thus will hamper the balance of the
ecosystem. Moreover these large glaciers reflect light back
into the space and with meltdown of
these glaciers, earth will be further warmed.
2. Climate Change: Irregular weather patterns have already
started showing results. Increased
precipitation in the form of rain has already been noticed
in polar and sub Polar Regions . More
global warming will lead to more evaporation which will
cause more rains. Animals and plants
cannot easily adapt to increase rainfall. Plants may die due
to it and animals may migrate to other
areas, which can cause entire ecosystem out of balance.
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3. Droughts: Large scale evaporation will be the major cause
of droughts in many places
particularly Africa .
Although, it is reeling under the huge pressure of water crisis, increased
global warming would further make the situation worse and
will cause malnutrition.
4. Diseases: As the temperature becomes warmer, it will have
an effect on the health of humans
and the diseases they are exposed to. With the increase in
the rainfall, water borne diseases are
likely to spread specially malaria. The earth will become
warmer and as a result heat waves are
likely to increase that will cause a major blow to the
people particularly in Europe.
5. Hurricanes frequency: As the temperature of the oceans
rises, hurricanes and other storms are
likely to become stronger. With the increase in the global
warming the water in the ocean warms
up and it heats up the surrounding air, creating hurricanes.
More water evaporation means more
hurricanes.
6. Agriculture: Global warming will affect agriculture.
Although the results are not visible yet,
but it may show its colours in years to come. As the global
temperature will increase plants will
find it harder to survive and will die. Plants are the major
source of food for human beings and as
a result food shortage will occur. The shortage of the food may
lead to war and conflicts in some
countries.
Steps To Control Global Warming:
i) Use Public Transport:
ii) Use Renewable Energy Like Wind Power:
iii) Burn Methane:
iv) Use Smart Cooler, Heater & Air Conditioner
v) Tune up and maintain vehicles properly
vi) Reduce electricity usage to the maximum
vii) Prefer recycling.
Ozone Depletion:
Ozone:
Ozone is a highly reactive and unstable gas, which is formed
by the recombination of oxygen
(O2) atoms in the presence of intense radiation. Its symbol
is O3.
Ozone Layer:
The ozone layer is a naturally occurring zone found in the
stratosphere, situated between 10-15 kms above the surface of the Earth. The
main function of the ozone layer is to act as a
shield against ultraviolet (UV) radiations from the Sun
because these rays are harmful to life.
Ozone Depletion:
Destruction of the stratospheric ozone layer which shields
the earth from ultraviolet radiation
harmful to life. ...
Causes Of Ozone Layer Depletion:
The Main Ozone-Depleting Substances (ODS)
• Chlorofluorocarbons (CFCs)
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• The most widely used ODS, accounting for over 80% of total
stratospheric ozone depletion.
• Used as coolants in refrigerators, freezers and air conditioners
in buildings and cars
manufactured before 1995.
• Found in industrial solvents, dry-cleaning agents and
hospital sterilants.
• Also used in foam products — such as soft-foam padding
(e.g. cushions and mattresses) and
rigid foam (e.g. home insulation).
• Halons
• Used in some fire extinguishers, in cases where materials
and equipment would be
destroyed by water or other fire extinguisher chemicals. In
B.C., halons cause greater damage
to the ozone layer than do CFCs from automobile air conditioners.
• Methyl Chloroform
• Used mainly in industry — for vapour degreasing, some
aerosols, cold cleaning, adhesives
and chemical processing.
• Carbon Tetrachloride
• Used in solvents and some fire extinguishers.
• Hydro fluorocarbons (HCFCs)
• HCFCs have become major, ―transitional‖ substitutes for
CFCs. They are much less
harmful to stratospheric ozone than CFCs are. But HCFCs they
still cause some ozone
destruction and are potent greenhouse gases.
OR
The cause of ozone depletion is the increase in the level of
free radicals such as hydroxyl radicals,
nitric oxide radicals and atomic chlorine and bromine. The
most important compound, which
accounts for almost 80% of the total depletion of ozone in
the stratosphere are
chlorofluorocarbons (CFC). These compounds are very stable
in the lower atmosphere of the
Earth, but in the stratosphere, they break down to release a
free chlorine atom due to ultraviolet
radiation. A free chlorine atom reacts with an ozone
molecule (O3) and forms chlorine monoxide
(ClO) and a molecule of oxygen. Now chlorine monoxide reacts
with an ozone molecule to form
a chlorine atom and two molecules of oxygen. The free
chlorine molecule again reacts with ozone
to form chlorine monoxide. The process continues and the
result is the reduction or depletion of
ozone in the stratosphere.
Effects Of Ozone Depletion
Following are the major effects of ozone layer depletion.
i) It will increase the risk of skin cancer
ii) It has resulted in melanomas, a kind of tumour.
iii) It greatly affects eyes and produces disease of vision.
iv) It suppresses immunity system of human beings.
v) UV rays damage various crops.
vi) It kills plankton and fish larvae.
vii) It causes sunburn in human beings.
viii) It causes spotting of leaves in plants and trees, thus
decreases productivity of the plants.
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Acid Rain:
―The rainwater which contains a large amount of poisonous
acids like sulphuric acid,
sulphurous acid, nitrous acid and other pollutants is known
as the Acid Rain.‖
Formation of Acid Rain
Acid rain is caused by a chemical reaction that begins when
compounds like sulphur dioxide
and nitrogen oxides are released into the air. These
substances can rise very high into the
atmosphere, where they mix and react with water, oxygen, and
other chemicals to form more
acidic pollutants, known as acid rain. Sulphur dioxide and
nitrogen oxides dissolve very
easily in water and can be carried very far by the wind. As
a result, the two compounds can
travel long distances where they become part of the rain,
sleet, snow, and fog that we
experience on certain days.
Causes Of Acid Rain:
Human activities are the main cause of acid rain. Over the
past few decades, humans have
released so many different chemicals into the air that they
have changed the mix of gases in
the atmosphere. Power plants release the majority of sulphur
dioxide and much of the
nitrogen oxides when they burn fossil fuels, such as coal,
to produce electricity. In addition,
the exhaust from cars, trucks, and buses releases nitrogen
oxides and sulphur dioxide into the
air. These pollutants cause acid rain.
OR
The main causes of acid rain are…
Natural Sources:
• Lightning strikes (cause nitrogen molecules to be
oxidized)
• Combustion of hydrogen sulphide (hydrogen sulphide is
formed from the breakdown of
sulphates in organic matter in the absence of oxygen-
anaerobic conditions). This reaction forms
sulphur dioxide.
Human Sources:
• Combustion engines (car, airplanes etc.)
• Burning of fossil fuels and coal
• Some mineral ores contain sulphur dioxide, and this is
released when the minerals are
processed.
Effect Of Acid Rain:
i) Kills flora and fauna
ii) Damages the buildings
iii) Causes skin cancer
iv) Increases the acidity of the soil
v) Kills fish and other aquatic animals
vi) Pollutes the water
vii) Causes spotting of leaves
viii) Causes corrosion of metal, painted surfaces and even
stone buildings and monuments.
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Ecosystem:
Definition:
A natural of habitat or system where living organisms and
physical components of their
environment interact with one another and exchange materials
so as to achieve a functional
stability is called an ecosystem.
Characteristics Of Ecosystem:
• An ecosystem is a basic unit of ecology of living
organisms.
• An ecosystem may be natural like a pond, lake, stream,
river, ocean or a forest.
• It may also be artificial like an Aquarian, an artificial
pond or an agricultural field.
• A pond is an excellent example of a small ecosystem to
demonstrate interrelationship between
abiotic and biotic component of the ecosystem.
Components Of Ecosystem:
i) Abiotic Components Of Ecosystem.
Following are the abiotic components of ecosystem.
a. Light
b. Temperature
c. Water
d. Atmosphere and wind
e. Fire
f. Soil
g. Topography
h. Gravity
i. Inorganic nutrients
ii) Biotic Factors.
Following are the biotic components of ecosystem.
a. Producers: Green Plants
b. Consumers: Animals and Man
c. Decomposers and reducers: Bacteria, fungi
Types Of Ecosystem:
There are two main types of ecosystem:
i) Terrestrial Ecosystem: it includes Forest and Desert
Ecosystem
ii) Aquatic Ecosystem: it includes small pool, a pond,
stream, river, lake and an oceanic
ecosystem.
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Environmental Pollution:
―Destabilization of the balance of the atmospheric
composition.
OR
―It is an unstable change in the composition of the
environment due to its physical, chemical and
biological changes, which is harmful for human life and
other animals living on the earth.‖
Types Of Pollution:
i) Air pollution
ii) Water pollution
iii) Land pollution
iv) Noise pollution
v) Industrial pollution
vi) Commercial or domestic sector pollution
vii) Chemical pollution
viii) Radioactive pollution (contamination)
Causes of Pollution
The ultimate cause of pollution is human activity itself.
Pollution is a human contribution to
nature. Science has evolved technologies and technologies
have helped the human welfare. In the
process, the pollution has been a part of technology and
therefore a part of human miseries.
Human activities mainly include:
• Industries for various human needs - directly and
indirectly
• Agriculture for food production and industrial needs
• Health care for health of human beings and animals
• Transport for mobility of human beings
• Dwelling for settlement in city or villages
• Energy for various direct human needs and industrial
needs.
Pollutants:
Pollutants are those substances which alter the natural
composition of the atmosphere or destroy
it to harmful level.
Types Of Pollutants:
1. Primary Pollutants
Primary pollutants are those substances which are directly
produced by a process. These are:
ix) Sulphur oxides
x) Nitrogen oxides
xi) Carbon monoxide (CO)
xii) Carbon dioxide
xiii) Volatile organic compounds (VOC), such as hydrocarbon
fuel vapours and solvents
xiv) Particulate matter (PM), such as smoke and dust.
xv) Metal oxides, especially those of lead.
xvi) Chlorofluorocarbons (CFCs)
xvii) Ammonia (NH3)
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xviii) Garbage, sewage and industrial wastes.
2. Secondary Pollutants
Secondary pollutants are those pollutants which are not
emitted. Rather, they form in the air when
primary pollutants react or interact.
These are:
i) Ground level ozone (O3)
ii) Nitrogen
dioxide
iii) Peroxyacetyl
nitrate (PAN)
Effects Of Pollution:
1) Air Pollution: Irritation of eyes, nose, mouth and
throat, Increased respiratory disease, Cancer,
Reduced lung functioning, Premature death. Acid rain, Ozone,
2) Water Pollution: Waterborne diseases such as; Typhoid,
Hepatitis, diarrhoea, vomiting, and
stomach aches, death of aquatic animals, May disrupt
photosynthesis in aquatic plants
3) Soil Pollution: Causes cancers including leukaemia,
developmental damage to the brain,
kidney damage; depression of the central nervous system,
Also causes headaches, nausea, fatigue,
eye irritation and skin rash, Contamination of crops, reduce
crop yields.
Water Pollution:
Definition:
―The presence of undesirable substances into fresh and
natural water which cause harmful
diseases in human beings as well as aquatic life is called
water pollution.‖
Types Of Water Pollution:
Following are the major types of water pollution.
i) Sea-water Pollution
ii) River water Pollution
iii) Land Water Pollution
Causes Of Water Pollution:
1) Pollution Through Domestic Activities:
Domestic activities pollute the water when following kinds
of wastes are added.
i) Soap and detergents
ii) Chemicals used in the houses
iii) Waste from slaughter house
iv) Waste from hospitals
v) Waste from bakeries
vi) Human and animal faeces
vii) Waste food
2) Pollution Through Industrial Activities:
Industrial sector is a great source of pollution of water
and air. Many industrial units produce
waste materials in the shape of solids, liquids and gases.
The industrial wastes are.
i) Poisonous gases
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ii) Acids, bases and harmful salts
iii) Pesticides and plastics
iv) Radioactive wastes
v) Toxic wastes from fertilizer factories
vi) Wastes from chemical factories
Water Pollution In Pakistan:
In Pakistan people do not take pain to dispose the waste
materials in a proper way. Instead of
dumping wastes in the drums and places meant for them they
freely throw these into the water
drains.
Water pollution is very prominent and widespread as a result
of urban and industrial activity.
Sewage waste from cities and industrial waste are the main
factors of water pollution. Many other
kinds of wastes which pollute water are from agricultural
lands which contain pesticides, waste
foods, fertilizers and animal excreta. Wastes from power
plants contain radioactive materials, hot
water and minerals which also pollute the water. Soaps,
detergents, human excreta, animal faeces,
wastes from slaughter houses, disease causing
micro-organisms from patients and chemicals etc.
are drained into water which causes massive water pollution.
Two Important Industries Of Pakistan Causing Water Pollution:
1) One of the biggest sources of water pollution is the
tanning and leather industry. The industry
uses toxic chromium metal and many other toxic
substances/chemicals. These toxins are released
in natural waters. Effluent of this industry has polluted
ground water and water of nearby rivers.
This industry is frequent in Kasur and Sialkot area.
2) Pesticide industry in Kala Shah Kaku near Lahore releases huge
quantity of acids, pesticides
and other dangerous wastes. These wastes are getting entry
into a stream flowing nearby. The
water of the stream is dangerously polluted. This water
ultimately goes to the rivers.
Effects:
i) Bacteria, viruses, protozoa and worms are carried in
polluted water. The diseases caused by
them are as under:
a) Bacteria: Typhoid, cholera, Dysentery, enteritis.
b) Viruses: Hepatitis, Polio, Viral enteritis.
c) Protozoa: Amoebic dysentery, diarrhoea.
d) Parasitic worms: Schistostomiasis
ii) It causes death of aquatic animals.
iii) It decreases the fertility of the soil and results in
low production.
Methods To Control Water Pollution:
Different methods can be used to control water pollution.
i) The whole sewage waste should be dumped after any
treatment.
ii) Sewage treatment plants should be installed in cities.
iii) The sewage waste must not be drained in river to save
water from pollution.
iv) Industrial waste should be treated before reaching
natural water.
v) Industries should be established away from cities and
rivers.
vi) Nuclear dumping in oceans should be banned.
vii) Modern scientific methods should be used in
agriculture.
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Deforestation:
It is the process of destruction of the forests.
Causes Of Deforestation:
A number of agents are responsible for removal of forests.
These are fires. Droughts or animals.
The principle agent of deforestation is man himself. Humans
are cutting forests to colonize the
forest areas or to prepare more agricultural lands or for
getting food.
Effects Of Deforestation:
i) Deforestation has many bad effects on human life. With
destruction of the forest the process of
cleaning of air and production of oxygen is badly affected.
ii) Forests are major agents of evaporation and rainfall.
With deforestation rainfall is decreased.
iii) With cutting of forests, pollution is increasing as the
hazardous gases are not completely
absorbed by plants.
iv) With deforestation carbon dioxide is increasing which is
causing global warming.
v) With reduction in area of forest, soil erosion is taking
place resulting in floods which destroy
crops and human life.
vi) Deforestation has badly damaged wild life and reduced
recreation sites.
Earth:
Features Of Earth:
i) The earth is the fifth largest planet of the solar
system, where life exists.
ii) Its equatorial diameter is 7,927 miles.
iii) Its polar diameter is 7900 miles.
iv) The earth has average density of 5 ½ g/cc.
v) the rotation period of the earth is 23 hours, 56 minutes
and 4 seconds.
vi) the revolution period of the earth is 365 days.
vii) The total mass of the earth is 6*1021 tons.
viii) The earth is composed of shells or layers, which are,
the crust, mantle and core.
ix) It is surrounded by a blanket of gases, which is known
as the atmosphere, mainly composed of
Nitrogen and Oxygen.
x) The surface of the earth is rich in oxygen, silicon,
iron, magnesium, sodium etc.
Structure Of The Earth:
The earth comprises of the following layers:
a) The crust
b) Moho discontinuity
c) The mantle
d) The Core
a) The Crust:
i) It is the outermost layer of the earth.
ii) It extends to about 25 miles (40kms) and comprises of
rocks.
iii) The crust is divided into the oceanic and the
continental crust.
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iv) Out of these the oceanic crust is 808 meter thick and
consists of sedimentary mud.
v) The continental crust is divided into upper continental
and lower continental crust.
b) Moho discontinuity:
i) The sharp boundary between the crust and mantle is called
Moho Discontinuity.
c) The Mantle:
i) The layer of the earth lying below the crust and above
the core is known as the mantle.
ii) It is almost 2900 kms (1800 miles) thick and comprises
about 80% of the volume of the earth.
iii) The chemical composition of the entire mantle is fairly
homogenous.
iv) However, temperature and pressure increases with depth.
v) The behaviour of the earthquake waves as they travel
through the mantle further tells us that it
consists of several layers and they are:
a) Lithosphere
b) Asthenosphere
c) Mesosphere
d) The Core:
i) The innermost part of the earth is known as the core.
ii) It extends from the base of the mantle to the centre of
the earth.
vi) This portion consists of melted iron and nickel that is
why it is known as Nife.
vii) The density of this molten mass of the core is 345
pounds per cubic feet.
Types Of Movements Of Earth:
• There are two types of motions of the earth.
• One is around its own axis which is called Rotation. One
rotation completes in 23 hours, 56
minutes and 4 seconds.
• The other motion of earth is round the sun, and is called
revolution of the earth.
• One revolution completes in 365 days.
• Northern end of the earth‘s axis is called the North Pole
and the Southern end is called South
Pole.
• An imaginary line drawn round the earth midway between the
poles is called equator.
• The path which the earth takes round the sun is called
earth‘s orbit.
Effects Of These Movements:
• Rotation of earth round its axis cause days and nights.
• That portion of earth, which is within the circle of
illumination caused by the rays of sun, has its
day.
• The other side earth, which is away from sun, remains dark
and therefore has its night.
Longer And Shorter Days:
• The circular areas near the North and South Pole of the
Earth are called Arctic and Antarctic
circles, respectively.
• These are situated at 66 ½0 North and 66 ½0 South of the
equator, respectively and form limits
of polar region.
• On June, the earth is in position A. north pole is
inclined towards the sun and south pole is away
from it.
• Obviously any place in Northern Hemisphere will have
longer days because it remains in light
for more than half the time of earth‘s rotation.
• Places on equator remains in light for half the time
making days and nights equal in this region.
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• The southern hemisphere remains in light for less time
than half the rotation of earth so the days
are shorter here.
• Positions of days and nights in the northern and southern
hemisphere are reversed on 22nd
December, when the earth completes its half revolution
around the sun, so days are longer in
southern hemisphere than those in the north.
Change Of Season:
• The second type of motion of earth is round the sun and is
called revolution of the earth.
• This is the cause of change of seasons.
• On June 21, the earth is in position A, when the north
pole is inclined towards sun while the
south pole is away from it.
• As the sun rays fall vertically and for a longer period in
the northern hemisphere, it is summer
here but in the southern hemisphere it is winter.
• On December 22, when the earth completes half revolution,
the conditions become reversed; it
is summer in the southern hemisphere and winter in the
northern hemisphere.
Atmosphere:
The layer of the gases which surrounds the earth is known as
the atmosphere.
OR
The atmosphere is a thin layer of the gases held to the
earth by the gravitational attraction.
OR
Atmosphere is the huge blanket of gas that circles the
entire earth.
Composition Of The Atmosphere:
The atmosphere consists of:
i) Nitrogen:
78.03%
ii) Oxygen:
20.99%
iii) Argon: 0.94%
iv) CO2: 0.03%
v) Hydrogen:
0.01%
vi) Neon: 0.0018%
vii) Helium:
0.0005%
viii) Krypton:
0.0001%
ix) Ozone: 0.000001%
Layers Of The Atmosphere:
The atmosphere of the earth is divided into following
layers.
i) Troposphere
ii) Stratosphere
iii) Ionosphere
iv) Exosphere
Ionosphere is sub-divided into:
i) Mesosphere
ii) Thermosphere
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1) Troposphere:
i) Troposphere is the lowest layer of the atmosphere.
ii) It extends roughly to a height of 8 kms near the poles
and 16-18 kms at the equator.
iii) It is troposphere where the people, plants, animals and
insects live.
iv) It is the layer where all weather occurs that‘s why it
is also referred as ―The weather Zone‖.
v) In the Troposphere temperature gradually falls with
increasing altitude.
vi) There is a thin buffer zone between the troposphere and
stratosphere is called tropopause.
2) Stratosphere And Ozone Layer:
i) The second layer of the atmosphere is known as the stratosphere.
ii) The stratosphere extends from the tropopause to about
30-31 mile above ground level.
iii) The important ozone layer is found in this region where
heat is generated by absorption of
UV.
iv) Here the temperature either remains constant or increases
with altitude.
Stratopause:
It is the upper boundary of the stratosphere which occurs
beyond 52 kms. Here the temperature
remains constant with increase in height.
3) Ionosphere:
i) The third major layer of the atmosphere is the
ionosphere.
ii) It lies above the stratosphere.
iii) It lies between about 30 and 90 miles above the surface
of the earth.
iv) It is divided into mesosphere and thermosphere.
v) The ionosphere is bombarded by cosmic radiation and solar
x-rays, which causes the gases in
the ionosphere to ionize.
vi) Brilliant displays of colored lights in the sky called
Aurora Borealis in the northern
hemisphere and the Aurora Auralis in the southern hemisphere
occur when streams of electrically
charged particles from the sun (solar wind) ionize the
atmosphere gases.
4) Exosphere:
i) The uppermost layer of the atmosphere extending beyond
Ionosphere is called exosphere.
ii) Beyond 300 miles is the very rare field exosphere which
consists only of scattered atmosphere
of O, H and He.
Latitude:
Definition:
It is the distance on the surface of the earth measured in
degrees north and south of the
equator.
The equator is at zero degree where the poles are at 90
degree. The latitude of the north pole
is 900 North and that of south pole is 900 South.
Characteristics OF Lines Of Latitudes:
i) All lines of latitudes are parallel to the equator as
well as parallel to one another.
ii) Parallels in the north of the equator are north
latitudes while those in the south of equator
are known as south latitudes.
iii) They are drawn on the globe as circles running in east
to west direction.
iv) The length of the equator is the maxim um and it goes on
reducing till the pole is only a
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point.
Longitude
Definition:
The distance on the earth‘s surface measures in degrees east
and west of a line joining the
geographical north and south poles and passing through
Greenwich in England. Greenwich is
at zero degrees longitude.
The sun rays have highest altitude simultaneously on all the
places at a particular line of
longitude as a result of which these are also called as
Meridians (Meridian is a Latin word
which means Mid-way). Among the latitude, equator is the
longest and is taken as reference
line. But all the lines of longitude are of the same length
and selecting a longitude as lines of
reference is a serious problem.
Earthquake:
Earthquakes are those movements of the earth crust which
make the ground vibrated and
shake backwards and forwards or in simple words an
earthquake is trembling in the earth.
The shocks waves are generated at a point within the crust
called the focus, and the point on
the earth‘s surface vertically above the focus is called the
epicentre of the earthquake. The
shock waves travel in all directions from the focus. On the
earth‘s surface, the shaking is thestrongest near the epicentre. These waves are detected by
seismograph.
Occurrence Of Earthquake:
i) Earthquakes occur when rocks subjected to great stress
suddenly break, releasing the
accumulated energy, which shakes the ground. Vibrations
spread out from the epicentre like
ripples in water.
ii) It may also be caused by movements of the plates,
resulting from convection currents in
the hot mantle of the earth.
iii) Earthquakes are also associated with volcanic
activity-eruption of magma. Collapse of
mines can also produce small earthquakes.
Volcanoes:
An opening in the earth's crust through which molten lava,
ash, and gases are ejected.
Occurrence Of Volcanoes:
i) Rocks below the Earth have a very high temperature.
ii) The great pressure upon these keeps them in a semi-solid
state.
iii) If the pressure weakens, then some of rocks become
liquid.
iv) This liquid is called magma.
v) The magma forces its way into cracks of the crust and may
either reach the surface of the earth
where it forms lava and flow out.
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Types Of Volcanoes On The Basis Of Activity:
There are three types of volcanoes on the basis of volcanic
activity, which are as under.
i) Active Volcanoes:
Volcanoes are said to be active when they frequently erupt
or at least when they have erupted
within recent time.
ii) Dormant Volcanoes:
The volcanoes that have been known to erupt and show signs
of possible eruption in the future
are describes as dormant volcanoes.
iii) Extinct Volcanoes:
The volcanoes that have not erupted at all in historic times
but retain the features of volcanoes are
termed as extinct volcanoes.
Causes of The volcanoes Eruptions:
i) Seafloor spreading
ii) Convergence of lithospheric plates
iii) Percolation of cold water
iv) Orogenic Movements
v) High temperature in the interior of the Earth.
Rocks:
Igneous Rocks:
• The word igneous means the fires and the rocks formed by
solidification of molten rock
material known as magma are known as igneous rocks.
• The first minerals to crystalize out of the melt are
high-temperature minerals-the olivines and
pyroxenes, which are silicates of magnesium and iron.
• They tend to be denser than magma and so they sink,
leaving the remaining fluid deficient in
magnesium and iron.
• The next group of minerals to solidify are the feldspars
(silicates minerals of potassium, sodium,
calcium and aluminium); the magma thus loses its metallic
constituents first.
• Finally, any remaining silica crystalizes out as quartz.
• The entire solidification process therefore results in
dense iron-and magnesium-rich rocks and
less dense silica rich rocks from the same original fluid.
• In this way, different types of rocks can be seen in the
same rock mass.
• The most important igneous rocks are: a) Granite rocks b)
Gabboro rocks c) Basalt rocks
Sedimentary Rocks:
• Sedimentary rocks are formed from the deposition and
compaction or lithification of rocks and
mineral grains derived from other rocks.
• These grains broke away from existing rocks by the action
of water, wind and ice.
• Many sedimentary rocks begin their existence as loose
deposits of sand or gravel at the bottom
of a sea or lake, on beach, or in a desert.
•
• Later the sediment is lithified i.e. compressed into a
rock.
• Following are the major classes of sedimentary rocks:
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i) Calcareous sedimentary rocks
ii) Carbonaceous sedimentary rocks
iii) Siliceous sedimentary rocks
iv) Ferruginous sedimentary rocks
v) Arenaceous sedimentary rocks
vi) Argillaceous sedimentary rocks
vii) Rudaceous sedimentary rocks
Metamorphic Rocks:
• The word metamorphic has been derived from two Greek words
Meta means change and
Morpha means shape.
• Thus metamorphic rocks include those rocks that have been
changed either in form or
composition without disintegration.
• Metamorphic rocks are formed from igneous as well as
sedimentary rocks but are different from
them.
• Example:
i) Sandstone, made of quartz grains and silica cement,
becomes quartzite, a very hard metaphoric
rock that resist weathering.
ii) Limestone is converted into much denser and harder
marble.
iii) Mica, an igneous rock, is converted into schist after
metamorphosis.
iv) Sedimentary rock slate is converted into a slightly
higher grade metamorphic rock phyllite.
Branches Of Biology:
i) Zoology: Zoology is that branch of biology which deals
with the study of animals.
ii) Botany: Botany is that branch of biology which deals
with the study of plants.
iii) Microbiology: It is the branch of biology which deals
with the study of microorganisms such
as viruses, bacteria etc.
iv) Morphology: It deals with the shape and structure of
living organisms.
v) Histology: It is the microscopic study of tissues of
plants and animals.
vi) Cytology: It deals with the structure of cell and
organelles present inside the cell.
vii) Physiology: It deals with the study of functions of
different parts of plants and animals.
viii) Ecology: It is the science of ecosystem and explains
the relationship between organisms and
their environment.
ix) Taxonomy: It deals with the naming and classification of
organisms.
x) Genetics: It deals with the study of heredity and
variations.
xi) Biotechnology: It deals with the application of
biological processes.
xii) Haematology: Study of blood and its constituent cells.
xiii) Geology: Study of features and properties of earth and
its constituents rocks
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Characteristics Of Living Organisms:
Following are the main characteristics of living beings
which are not present in non-living
organisms.
i) Metabolism
ii) Growth
iii) Irritability
iv) Reproduction
v) Movement
vi) Nutrition
vii) Respiration
viii) Excretion
Virus:
• Viruses are the micro-organisms which are strict or
obligate parasites of animals or plant
cells.
• Many of the viruses are also parasites on bacteria.
• A large number of viruses cause diseases in plants and
animals.
Characteristics Of Virus:
• A virus consists of two components, a protein coat and a
core of nucleic acid which is either
DNA or RNA.
• DNA viruses are called adenoviruses and RNA viruses are
called retroviruses.
• The shape of a virus is due to its protein coat.
• Viruses are of many shapes i.e. rods, spherical, hexagonal
or icosahedral.
• Sometimes their shape is complicated.
• Virus replicate inside a living cell and many viruses are
synthesized along with their protein
coats and nucleic acid.
• The nucleic acid contains instructions for the shape of
the virus.
Diseases Caused By viruses:
i) Polio
ii) AIDS
iii) Smallpox
iv) Measles
v) Hepatitis
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Bacteria:
Characteristics Of Bacteria:
• Bacteria are unicellular prokaryotic organisms which
generally divide by transverse binary
fission.
• They possess rigid cell walls and act as pathogens
• Nucleus is not well organised
• No definite chloroplast, chlorophyll is dissolved in
chromoplasm.
• There are three forms of bacteria which are:
i) Round called Cocci
ii) Rod like called Bacilli
iii) Spiral called Spirrila
Classification Of Bactria According To Mode Of Nutrition:
According to mode of nutrition, there are three types of
Bactria:
a) Parasitic:
• Devoid of chlorophyll
• Are heterotrophic and get food from living animals and
plants
b) Saprophytic
• Lack chlorophyll hence cannot prepare their own food.
• Get food from dead organic remains
c) Autotrophic
• Contain chlorophyll
• Can synthesis food by photosynthesis
• Few get their food by chemosynthesis
Reproduction In Bacteria
i) Vegetative: By Binary Fission
ii) Asexual: By Formation of Endospores
iii) Sexual: By Conjugation
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Cell Division:
The process in which the cells divide and replicate. This
process is the basis for growth and
replication. There are two main types of cell division,
which are as under:
1) Mitosis
2) Meiosis
Mitosis:
A type of cell division in which a cell divides into two
identical daughter cells each having
same number of chromosomes as that of parent cell.
Stages Of Mitosis:
There are four stages of mitosis, which are as under:
i) Prophase
ii) Metaphase
iii) Anaphase
iv) Telophase
i) Prophase:
- Prophase is the first phase of mitosis.
- Chromatin material condenses and becomes visible
- The nucleolus of the cell disappears
- The nuclear membrane also disappears
- Centrioles begin to move opposite ends of the cell
ii) Metaphase:
- Metaphase is the second stage of mitosis.
- Chromosomes line up in the centre of the cell, separate
and become a pair of identical
chromosomes.
- The chromatids become uncoiled and apart from each other.
iii) Anaphase:
- It is the third phase of mitosis.
- During this phase each set of chromosomes move towards the
opposite end of the cell.
iv) Telophase:
- The fourth phase of mitosis is known as Telophase.
- During this phase spindle fibres disappear.
- Nuclear membrane appears
- Cell divides into two daughter cells
- Nucleolus re-appear
- The chromosomes disperse and are no longer visible.
Significance Of Mitosis:
1. Growth: The number of cells within an organism increases
by mitosis and this is the basis
of growth in multicellular organisms.
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2. Cell Replacement: Cells are constantly sloughed off,
dying and being replaced by new
ones in the skin and digestive tract. When damaged tissues
are repaired, the new cells must be
exact copies of the cells being replaced so as to retain
normal function of cells.
3. Regeneration: Some animals can regenerate parts of the
body, and productions of new cells
are achieved by mitosis.
4. Vegetative Reproduction: Some plants produce offspring
which are genetically similar to
themselves. These offspring are called clones.
Meiosis:
A type of cell division in a cell divides into four daughter
cells with having half number of
chromosomes as compared to parent cell.
Characteristics Of Meiosis:
• Takes place in sexual reproduction at the time of
formation of male and female gametes
• In animals it takes place during the formation of sperms
and ova while in plants during spore
formation
• Diploid cells reduce to haploid cells
• Consists of two consecutive divisions
• First division is reductional or meiotic and the second is
simple mitotic division.
Stages Of Meiotic Division:
i) Prophase I
ii) Metaphase I
iii) Anaphase I
iv) Telophase I
v) Prophase II
vi) Metaphase II
vii) Anaphase II
viii) Telophase II
Prophase I:
Prophase I consists of 5 sub stages, these are:
a. Leptotene
- Nucleus increases in size
- Chromosomes become long and uncoiled threads
- They become more visible
b. Zygotene
- Homologue (similar) chromosomes attract each other and
form pairs.
- This process is called synapses
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c. Pachytene
- Chromosomes become condensed due to widening of coils
- They form chiasmata i.e. cross each other in double nature
or bivalents.
d. Diplotene
- Homologous chromosomes go apart from each other except at
chiasmata
- Chromosomes become more short and thicker
e. Diakinesis
- The bivalents become more apart.
- Chromosomes become deeply stained
- Nucleolus and nuclear membrane disappear and spindles
become distinct
Metaphase I:
- Chromosomes now rearrange themselves in an equatorial line
- Spindles attach to the centrosome of the chromosomes
Anaphase I:
- Spindles start to contract
- Split the tetrahedral chromosomes into two chromatids and
drag them to opposite poles
- Here the reduction takes place.
Telophase I:
- Spitted chromosomes reach to opposite poles
- Nucleolus and nuclear membrane reappear
- At the end of Telophase I, prophase II starts.
Prophase II:
- Chromatin network breaks into bivalent chromosomes
- Nuclear membrane and nucleolus disappear and spindles
start to reappear
Metaphase II:
- Bivalent chromosomes rearrange themselves at equator
- Spindles attach to the centrosomes of each chromosome
Anaphase II:
- Spindles contract and split the chromosomes longitudinally
into two chromatids
- Each chromatid travel to opposite pole
Telophase II:
- Each chromatid reach to the opposite pole
- Spindles disappear and nuclear membrane and nucleoli
reappear
- As a result 4 nuclei are formed
Significance Of Meiosis:
- To allow trait inheritance in offspring
- To maintain diploid number in each generation
- To ensure the production of haploid gametes in sexual
reproduction
- To produce genetic variations among offspring
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Classification Of Plants:
Plants are those organisms which contain chlorophyll and
synthesize their own food through
photosynthesis. Plants are divided into:
1) Flowering Plants OR Phanerogams
2) Non-Flowering Plants OR Cryptogams
Flowering Plants:
Flowering plants are those plants which contain seed. These
are known as Phanerogams.
They are further subdivided into:
i) Gymnosperms
ii) Angiosperms
Gymnosperms:
Gymnosperms are those flowering plants which contain naked
and unprotected seeds.
Examples: Pine, Fir, Cedar, Spruce and Cypress etc.
Angiosperms:
Angiosperms are those flowering plants whose seeds are
protected by a fruit or seed pod.
Examples: Grass, Crops, Vegetables, Fruits and weeds.
Non-Flowering Plants:
Non-Flowering plants are also known as cryptogams. These are
the plants which do not have
seed or in other words they are seedless. Following are the
main characteristics of these
plants:
- They reproduce by spores
- They have long life
- They have no long fibres
- They cannot grow to greater size
- They generally have simple structure, except ferns.
Examples: Moses, Ferns, Algae.
Flower & Its Parts:
The flower is the reproductive part of the plant. It is
mainly concerned with formation of
seeds. It is regarded as the modified shoot for the purpose
of reproduction.
Parts Of Flower:
A typical flower consists of a short axis known as the
thalamus, on which floral leaves are
inserted in four distinct whorls, which are as under:
i) Calyx
ii) Corolla
iii) Androecium
iv) Gynaecium
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Calyx:
Calyx is the outermost whorl of floral leaves called sepals.
The sepals can be defined as the
green and leaf like structures which are mainly concerned
with the protective function.
Corolla:
Corolla is the second whorl of floral leaves called petals. The
petals are beautifully coloured
which are responsible for the attraction to the insects
towards them.
Androecium:
The third whorl of the leaves consists of stamens. It is
considered as the male part of the
flower.
Gynaecium:
Gynaecium is the inner most whorl of the floral leaves
called carpels. It is considered as the
female part of the flower.
Parts Of Plants:
i) Ginger: Modified Stem (rhizome) and it is also a root.
ii) Cinnamon: Bark of stem
iii) Radish: Root
iv) Potato: Stem (tuber)
v) Peanut: Seed
vi) Saffron: Stigma/flower
vii) Almond: Fruit
viii) Chillies: Fruit
ix) Spinach: Leaves
x) Tomato: Fruit
xi) Turnip: Root
xii) Carrot: Root
xiii) Cucumber: Fruit
Photosynthesis:
Definition:
Photosynthesis is a process in which plants manufacture
their food (simple carbohydrates) in
the presence of chlorophyll and sunlight by the combination
of carbon dioxide and water.
Raw Material For Photosynthesis:
i) Carbon dioxide: Taken from air
ii) Water: Absorbed by roots from soil
iii) Sunlight: From Sun
iv) Chlorophyll: green pigment present in leaves
By-Products Of Photosynthesis:
i) Carbohydrates (simple sugar): used by plants as a food
material and excess of it is
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converted into starch
ii) Oxygen: Released into air
Importance Of Photosynthesis:
i) Major process of food production in plants
ii) Utilization of CO2 of the atmosphere and liberation of
oxygen
iii) Important in reducing CO2 of the atmosphere which is
dangerous for the human beings as
well as animal health.
Pollination:
• It is the process by which seeds are produced.
Definition:
Pollination is the phenomenon of transfer of pollen from
male reproductive organ (anther) to
female reproductive organ (stigma) in flowering plants
through biological or physical agency.
Types Of pollination:
There are two types of Pollination
i) Self-Pollination:
In this type of pollination pollens are transferred to the
stigma in the same flower. Some
plants are by nature self-pollinated as wheat and grasses.
ii) Cross Pollination:
In this type the pollen grains are transferred from the
anther of one flower to the stigma of
another flower. The cross pollination is considered and
advantageous to the plant as the seeds
produced by cross-pollination are usually greater in number
and the plant germinated from
them are superior in vigour, height and weight.
Vehicles For Pollination:
Vehicles for pollination are animals, water, wind and insects.
Therefore cross pollination may
be:
a) Entomophily-by insects
b) Anemophily-by wind
c) Hydrophily-by water
d) Zoophily-by animals
Importance Of Pollination:
• Vital process for reproduction in plants
• Reproduction is carried out by reproductory organs of
plants due to pollination
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Fertilization:
The fusion of male and female gametes is called
fertilization.
Types Of Fertilization:
Following are the major types of fertilization:
i) External Fertilization
ii) Internal Fertilization
iii) Self-Fertilization
iv) Cross-Fertilization
External Fertilization:
• This type of fertilization is generally observed I simple
aquatic animals.
• In such animals both ova and sperms are released into the
water where fertilization occurs.
• In terms of evolution external fertilization is of
primitive type and is not better biologically as
compared to internal fertilization.
Internal Fertilization:
• In the internal fertilization the females keep ova inside
their bodies and males deposit sperms
within the tube of reproductive tacts of females.
• For all land animals internal fertilization is almost must
because sperms are quickly killed by
dehydration.
• In terms of evolution internal fertilization is highly
evolved and much better biologically as
compared to external fertilization.
Self-Fertilization:
• Self-fertilization occurs within the same animal.
• It is that fertilization in which sperms are used by the ovaries
of same animal e.g. Tapeworm
Cross-fertilization:
• Cross-fertilization is the process in which sperms of one
animal are transferred into the body of
another animal e.g. Earthworm.
Genetic Engineering:
The deliberate modification of the characteristics of an
organism by manipulating its genetic
material.
OR
Scientific alteration of the structure of genetic material
in a living organism. It involves the
production and use of recombinant DNA and has been employed
to create bacteria that
synthesize insulin and other human proteins.
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Significance Of Genetic Engineering:
i) To Cure the genetic disorders
Heredity diseases can possibly be treated by this technique
by transplanting normal genes in
the place of abnormal or diseased genes.
ii) To Prepare Better Crops
Crops with desired characteristics could possibly be
produced by introducing desired genes.
iii) To Get Better Breeds Of Animals
Like plants better breeds of animals can also be produced by
the introduction of recombinant
DNA.
iv) Interferon
Interferons are effectively used in the treatment of
Hepatitis of A & B.
v) Insulin
Human insulin is being produced by genetic engineering to
treat diabetes
vi) Vaccines
Genetic engineering has also helped in the production of
vaccines which are used for
controlling and treating viral diseases.
Biotechnology:
The exploitation of biological processes for industrial and
other purposes, esp. the genetic
manipulation of microorganisms for the production of
antibiotics, hormones, etc.
OR
Biotechnology is the use of living organisms (especially
microorganisms) in industrial,
agricultural, medical and other technological applications.
Importance Of Biotechnology:
i) To increases production
ii) To introduce improved quality of seeds and plants
iii) To introduce plants resistant to disease and insect
pests
iv) To introduce verities suited to particular climates and
soils.
v) To introduce verities resistant to lodging
vi) To improve nutritional value of crops
vii) To save rare varieties of plants by rapid clonal
propagation for breeders to use in future.
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Teeth:
The humans have two sets of teeth one replaced by the
second. The primary set or milk or
deciduous teeth are 20 in number while there are 32
permanent teeth in adults.
1. In children there are 20 deciduous or milk teeth. These
are
Incisor: 2 pair × 2= 8
Canine: 1 pair × 2= 4
Premolars: 2 pair× 2=8
2. In adults there are 32 permanent teeth. In each jaw on
each side there are:
Incisors: 2 pair × 2=8
Canines: 1 pair × 2=4
Premolars: 2 pair × 2=8
Molars: 3 pair × 2= 12
Incisors:
The central front teeth are called incisors. There are four
in upper jaw and four in lower jaw.
Canines:
The pointed, dark colored teeth on either side of the
incisors are canines. 2 in upper jaw and 2 in
lower jaw.
Premolars:
These are bi-cusped teeth after the canines. There are 8
premolars. 4 in the upper jaw and 4 in the
lower.
Molars:
There are 12 molars, 6 in the upper jaw and 6 in the lower
jaw.
Structure Of Teeth:
Each tooth consists of a crown which is the visible part and
the root, which anchors it in sockets
in the jaw. A tooth consists mainly of dentine. The crown is
coated with even harder enamel,
while the root is covered with cementurn to help another it
in the jaw. Inside each tooth, there is a
cavity full of pulp, carrying nerves and the tooth‘s blood
and eats through the dentine to the pulp
when the decay reaches the pulp, pain and inflammation
follows and tooth may die.
A nerve, an artery, a vein and lymph duct enters the pulp
cavity through the root canal. The
nerves give sensation of hot and cold.
Antibody:
Antibody is a protein produced by white blood cells that
help to destroy bacteria. Antibodies
react with the antigens and inactivate or destroy them. A
large number of antibodies are
produced in blood which are targeted against various types
of antigens. Antigens are foreign
molecules, cells, bacteria, viruses or fungi which enter the
body usually a disease causing
microorganisms. Antibodies are the integral part of the
defence mechanism of human body.
They are also involved in immunity against disease.
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Hemophilia:
• It is a disease in which the peron have prolonged blood
clotting time resulting in excessive
bleeding fron injury.
• It is due to the deficiency of vitamin K.
• It is a semilethal disease controlled by recessive gene.
• It is less common in women than in men.
Important Facts About Human Physiology:
The largest gland of the body: Liver
The largest organ of the body: Skin
The longest bone of the body: Femur
The total number of bones in the body: 206
The hardest bone of the body: Tooth
The smallest bone of the body: Stapes
Total number of muscles in the body: 600
The filter of the body: Kidney
The pump of the Body: Heart
Total number of bones in vertebral column: 33
The normal body temperature: 98.4 F (37 C)
The normal respiratory rate of the Body: 16-18 per min
The total volume of blood in body: 4-5 litres
Total number of bones in face: 14
Vascular connection between foetus and uterus: Placenta
Brain:
Human brain is contained in skull. It has three major parts.
i) The Cereberum ot bigger brain
ii) The Cerebellum or Smaller brain
iii) Medulla Oblongata or hind brain
The cereberum constitutes the major volume of brain. It
consists of two large masses of
nervous material known as cereberal hemispheres. Human
consciousness, thought, emotions,
sight, will, hearing, sensation of pain, memory and speech
are centere in the creberum. Some
parts of it also control motor nerves, operating the arms
and legs.
The cerebellum or the smaller brain is related with the
coordination of action of nerves and
muscles. In this way movements of body are manged. Medulla
or hind brain contains the
centres for reflex actions in addition to automatic
movements such as breathing and walking.
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Reflex Action:
- Reflex actions are the responsed to environmental changes
both internal and external and are
immediate or automatic and are without intervention of will.
- These reflexes amy be simple or conditioned e.g. watering
of mouth on seeing or smelling of
food.
- Simple reflexes are inborn, inherited or unlearnt
responses to stimuli.
- The structural and functional basis of simple reflex is
called reflex arc.
- Impulses are carried from receprtors to sensory neurons to
CNS from where they are passed on
via motor neurons to the effectors for necessary response.
Thermoplastics:
Substances (esp. synthetic resins) that become plastic on
heating and harden on cooling and
are able to repeat these processes
OR
A type of plastic that can be softened by heat, hardened by
cooling, and then softened by heat
over and over again.
Properties of Thermoplastics:
Thermoplastics have wide ranging properties.
- They can be very much like rubber, or as strong as
aluminium.
- are light in weight,
- Can withstand temperature extremes of up to 600 F, while
others retain their properties at -100 F. Some
- Thermoplastic materials have no known solvents at room
temperature.
- Most thermoplastic materials are excellent insulators,
both electrical and thermal.
- Are recyclable materials that are used frequently today to
create objects such as foam cups,
polyethylene squeeze bottles, acrylic lenses and safety
helmets.
- In general the combination of light weight, high strength,
and low processing costs make
thermoplastics well suited to many applications.
Uses:
- They are useful for a variety of applications, including
consumer goods, machine parts,
medical equipment and packaging and storage materials.
Examples:
• PVC/Vinyl
• Polystyrene
• Polyethylene
• Cellulose Acetate
• PTFE/Teflon
• Nylon/Polyamide
• Polyester
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Synthetic Polymers:
Polymers are composed of very large molecules
(macromolecules) formed by linking together
many smaller, more simple units called monomers. There can
be as few as five or as many as
several thousand monomers units in a polymer. There are a
large number of synthetic polymers
prepared and in use. Some of these are polyamides(nylon),
polyethylene, propylene,
polyvinylchloride, synthetic rubber, cellulose acetate,
cellulose nitrate and silicones.
Heredity:
Terminology Of Genetics:
Gene:
The basic unit of hereditary material which is responsible
for development of a trait.
Alleles:
Alternatives forms of genes are called alleles, e.g. tall
versus dwarf.
Dominant:
The dominant alleles are those traits which show complete
expression even in heterozygous state.
Dominant alleles dominate the recessive alleles in
heterozygous state.
Recessive:
Recessive alleles or traits are those which fail to express
themselves in heterozygous state. For
example r and y are recessive alleles for wrinkle and green
seeds.
Homozygous:
Homozygous is a condition in which an individual possess
similar alleles for a particular trait. For
example TT for tallness and tt for dwarfness.
Heterozygous:
Heterozygous is a condition in which an individual possess
dissimilar alleles for a particular trait.
For example Tt for tallness.
Genotype:
Genetic make of an organism is called genotype.
Phenotype:
External appearance or expression of genotype is called
phenotype. For example, roundness,
wrinkleness of seeds and tall or dwarf plants represent
different phenotype.
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Gene:
Definition:
The fundamental unit of heredity, formed as a sequence of
bases in DNA.
Characteristics Of Genes:
• Each gene has a definite position at the chromosome and
may occur as alleles.
• The name gene was introduced by Johannsen in 1909 and the
structure of DNA was elaborated
by Watson and Crick in 1953.
• Genes determine all the structural and functional
characters of an individual, like eye colour,
skin colour, height, weight, blood group, hair,
intelligence, temperament and all others.
• The characters from one generation to other are taken by
genes.
• They sometimes change through the process of mutation.
This gives variety in characters.
• The accurate structure of the proteins and enzymes in the
body is determined by genes.
Chromosomes:
A chromosome is a rod-like portion of the chromatin of a
cell nucleus, performing an important
part in meiotic cell division, and in the transmission of
heredity characteristics. Normally they are
constant in number for any species; there are 22 pairs of
chromosomes and two sex chromosomes
in the human.
Types Of Chromosomes: in higher animals and plants, there
are two fundamental types of
chromosomes, which are classified on the basis of sex
determination these are:
i) Autosomes
ii) Sex Chromosomes:
Autosomes:
These are paired somatic chromosomes that play no part in
sex determination of organisms.
These chromosomes are similar in males and females.
Sex Chromosomes:
The chromosomes that determine sex in organisms are called
sex chromosomes. There are two
types of sex chromosomes.
a) X- chromosome
b) Y- Chromosome
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Animals:
Types Of Animals:
i) Invertebrates: Animals having no backbone or vertebral
column.
ii) Vertebrates: Animals with backbone or vertebral column.
Classification Of Invertebrates:
The invertebrates are classified into following categories:
i) Phylum Protozoa
ii) Phylum Porifera
iii) Phylum
Coelentrata
iv) Phylum
Platyhelminthes
v) Phylum
Nematode
vi) Phylum Annelida
vii) Phylum Mollusca
viii) Phylum Arthropoda
ix) Phylum Echinodermata
Following are the most common examples of invertebrate
animals with their relative phyla:
- Euglena: Phylum Protozoa
- Paramecium: Phylum Protozoa
- Amoeba: Phylum Protozoa
- Sponges: Phylum Porifera
- Hydra: Phylum Coelentrata
- Jelly fish: Phylum Coelentrata
- Tapeworm: Phylum Platyhelminthes
- Ascaris: Phylum Nematode
- Hookworm: Phylum Nematode
- Filaria: Phylum Nematode
- Snails: Phylum Mollusca
- Squids: Phylum Mollusca
- Cockroach: Phylum Arthropoda
- Honey bee: Phylum Arthropoda
- Mosquito: Phylum Arthropoda
- Butter fly: Phylum Arthropoda
Classification Of Vertebrates:
Vertebrates have been divided into following five major
classes:
i) Fishes
ii) Amphibians
iii) Reptilian
iv) Birds
v) Mammals
Some Animals & Their Location
i) Blue whale: Found in all oceans
ii) Panda: China
iii) Dolphin: In seas
iv) Porpoises:
v) Kangaroo: Australia
vi) Snow Leopard: Central Asia
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vii) Yak: Central Asia
viii) Llama: South America
ix) Ibex: Wild mountain goat
x) Cobra: South Asia
xi) Alligator: N.America
xii) Tortoise: Water
xiii) Rattle Snake: America
xiv) Lizards:
xv) Crocodiles:
xvi) Ostrich: Deserts Of Africa
xvii) Penguin: Antarctic Region
xviii) Kiwi: New Zealand
xix) Rhea: South America
xx) Emu: Australia
xxi) Shark: Found in all oceans
xxii) Trout: Fresh water fish
xxiii) Cod:
Scavenger:
Scavengers are the animals that ‗Clean up‘ after the other
animals by consuming their leavings and
sometimes prey on sick or dying animals or consume dead
bodies. Scavengers are also called detritus
feeders. Vultures, coyotes, jackals, hyenas and wild dogs
are scavengers which eat the left over prey or
dead bodies of hunted animals.
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