GENERAL KNOWLEDGE ~ General Science 367

• Focal length of plane mirror is infinity. i.e. Uses of Mirrors

power of the plane mirror is zero.
•
1. Plane mirrors are used as looking
Linear magnification produced by plane
1.
glass.
mirror is
2. Concave mirror is used as shaving
• When two plane mirrors are kept facing
each other at an angle and an object mirrors, used by doctors, shades of
placed between them, then table lamp, for search lights.
(a) Number of images, 3. Convex mirror is used as back view
360° mirrors in vehicles, in street lamps etc.
Refraction of Light

e
360° is even or
the object lies• When a ray of light passes from
one medium to other, it bends from
symmetrically.

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its path. This phenomenon of
(b) Number of image, bending of light ray is called as
360° is refraction of light.
odd or the
When a ray of light travels from one
object lies asymmetrically. medium to another the wavelength and
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velocity of light changes, but the
Reflection at Spherical frequency does not change.
Surface
. Laws ofRefraction
Spherical mirrors are the miiTrors in There are two laws
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of refraction
which reflecting surface side is spherical.
(i) The incident ray, the refracted ray
There are two types of spherical mirrors and the normal at the point of
(i) Convex mirror incidence all lie on the same plane.
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(ii) Concave mirror (ii) The ratio of the sine of the angle of
Mirror formula is given by-+ incidence to the sine of the angle of
u= object distance, refraction is a constant for a given
medium
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V=image distance
f=focal length of the mirror sin
Magniication (n)
Length (height) of inmage where, Hg is called refractive index of
second medium with respect to first
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Length (height) of object medium.

Image Formation by Concave Mirror

Position of Object Position of Image Size of Image Nature of Irmage
At infinity AtF Highly diminished Real and inverted
Between infinity and C Between F and C Diminished Real and inverted
At C AtC Same size Real and inverted
BetweenFand C
Belween infinity andC Enlarged Real and inverted
AtF At infinity Highly enlarged Real and inverted
Between F and P Behind the mirror Enlarged Virtual and erect

where, C is centre of cuvature, P is pole of the mirror and F is focUs.

Image Formation by Convex Mirror
Position of Object Position of Image Size of Image Nature of Image
At infinity AtF Highly diminished Erect and virtual
Between infinity and pole Between F and P Diminished Erect and virtual

where, F is focus, P is pole and C is centre of Cuvature.

368 GENERAL KNOWLEDGE~ General Science

• Twinkling of stars is based upon This phenomenon is called scattering

refraction. of light.
• Due to relraction, rivers appear shallow,• Red colour of light is scattered least and
coin in a beaker filled vith water appears violet colour of light is scattered most.
raised, pencil in the bealker appear Therefore, danger signals are of red
broken. colour.
• At sunset
and sunrise, due to refraction, • Blue colour of sky is due to scattering of
Sun appears above horizon, vhile it is light. The brillant red colour of rising
actually below horizon. and setting Sun is due to scattering of
• The duration of day appears to be light.
increased by nearly 4 min due to • Clouds appear white due to scattering

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atmospherie refraction. of light.
• Writing on a paper appears lifted when a
Optical Fibre

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glass slab is placed over the paper.
• The refractive index of a medium is It is a device based on total internal
maximum for violet colour of light and reflection by which
a
light signal can be
transferred from one place to the other
. minimum for red colour of light.
Refractive index decreases with rse in the with a negligible loss of energ.
ra Itis used in testing the internal organs of
temperature. human body i.e. endoscopy.
Total Internal Reflection Lenses
ofLight Lens is a transparent medium bounded
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• When a light ray goes to rarer medium by two curved surfaces. Lenses are of
from denser medium, then as we increase two types
the angle of incidence, angle of refraction (i) Concave or divergent lens.
ie

also inceases. The angle of incidence for (ii) Convex or convergent lens.
which the angle of refraction becomes 90°
is called eritical angle.
• If the angle of incidence in denser
jm

medium is greater than critical angle (C),

then the ray is reflected back into the 2F1 F1 F2 2F2
denser medium, this phenomenon is
called total internal reflection. It is Convex lens
necessary for the total internal reflection
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of light to occur that the light ray should whee, O = optical centre
go to rarer medium from denser medium.
F = frst focus
• Angle of incidence in denser medium Fo = second focus
should be greater than critical angle.
• In desert, the phenomena of mira e Lens formula is given by1
occurs due to total internal reflection.
• The air bubbles in glass paper weight
appear silvery white due to total internal
reflection. Sparkling of diamond is due to
multiple total internal reflection taking 2F1 F
O
2F2
place inside the diamond.

.Scattering of Light Concave lens

When ray passes
light through a medium Magnification ()
in which particles are suspended, whose
szes are of the order of wavelength of Length (height) of imagev
light, then light on striking these Length (height) of object u
particles, deviated in different directions.
GENERAL KNOWLEDGE ~ General Science 369

Image Formation by a Convex Lens Dispersion of Light

Position of Position of Size of Nature • When a narrow beam of light is
Object Image Image of Irmage incident on a prism, the emergent
At infinity beam is not only deviated, but at the
AtF Highly Real and
same time splits up into a coloued
diminished inverted
band of seven colours. This
Beyond 2F Between F Diminished Real and
and 2F, inverted phenomenon is called dispersion of
Same size light.
At 2F, At 2F Real and
inverted • The seven colours of band are violet,
Between indigo, blue, green, yellow, orange and
2F, and F
Beyond 2F Enlarged Real and
red.

e
inverted
AtF At infinity Highly Real and Violet colour deviates through maximum
enlarged inverted angle and red colour deviates through

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Belween E Behind the Enlarged Virtual
the minimum angle.
and lens object, on and • Red, green and blue are called primary
the same erect colours or basic colours.
side of the
object Mixing of Colours
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• Red + Green + Blue = White
Image Formation • Red + Blue = Magenta
by a Concave Lens • Blue + Green = Peacock blue
Position of Position Size of Nature of (or Cyan)
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Object of Irmage Image Irmage • Red + Green = Yellow

At infinity AtFa Dirminished Erect and • If all the colours of white light are
virtual reflected back from the object, then it
appears white.
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Between Belween Diminished Erect and

infinity F and virtual • And if all the colours of white light is
and lens lens absorbed by an object, then it appears
black.
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If the lens is immersed in a medium having

Polarisation is the only phenomenon
refractive index more than that of lens, then the which proves that light is a transverse
nature of the lens changes i.e. convex lens wave.
behaves as convave lens and vice-versa. The layer of kerosene oil over water
If the lens is immersed in a medium having
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surface appear coloured in the

refractive index equal to that of the lens, the presence of sunlight due to proper
lens behaves as a plane glass plate.
interference of light.
An air bubble in water behaves as a concave
lens. HUMAN EYE
• It is an optical instrument just like a
Power of Lens photographic camera. It forms the real
• It is the reciprocal of focal length of lens. It image of the object on retina of the
is measured in metre. eye.
1 • For the normal eve, the range of vision
P
f(m) is from 25 cm to infinity.
• Its unit is dioptre (D). Defects of Vision Myopia
Prism • In this case, the person cannot see the
distant object clearly.
• It is a uniform transparent refracting
Image is formed before the retina.
medium bounded by two plane surfaces
inclined at certain angle. Concave lens is used for correcting
myopia.
370 GENERAL KNOWLEDGE~ General Science

Hypermetropia Compound Microscope

• In this case, the person cannot see near • It consists of two convex lenses.
object clearly. In a compound microscope the focal
.
Image is formed behind the retina. length of the objective lens is short
• Convex lens is LIsed for correcting and that of the eyepiece is slightly
hypermetropia. greater than it. The final image
formed by the compound microscope
Astigmatism is inverted, magnified and virtual.
• In this case, the curvature of cornea becomes Magnifying power =0
irregular and image is not clear. Cylindrical

e
lens is used for correcting astigmatism. where,
Vo =
Presbyopia distance of image from the
objective

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•
In old age the power of accommodation of uo = distance of object from the
the eye lens decrease, therefore, neither near objective
nor
distant objects are clearly seen.
Presbyopia can be renmoved by using bifocal Telescope
lenses.
ra • It is used to see the magmified
Cataract images of the distant objects.
• In this defect, an opaque, white
membrane is There are two types of telescopes
developed on cornea due to which a person (i) Astronomical telescope
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loses power of vision partially or completely. (ii) Galilean telescope

. In an astronomical telescope, the
This defect can be removed by removing this
membrane through surgery. objective lens is a convex lens of
large focal length, but eye-piece is a
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convex lens of short focal length.

SIMPLEMICROSCOPE
• It consists of a convex lens of short focal Magnifying power = 4)
length.
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• It is used to see the magnified images of very • In Galilean telescope, the objective
sImall objects. lens is a convex lens of large focal
D length, but the eye-piece is a
Magnifying power concave lens of short focal length.
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Electricity
Electric Charge where, e=+1.6 x 10-1°c
• It is something that a body attains when it Conductors are those substances
loses or gains the electrons. which allow passage of electrical
• The positive and negative labels and sign for charge to flow through them and
electric charges were chosen arbitrarily by have very low electrical resistance.
.
Benjamin Franklin. Metals like silver, iron, copper are
Similar charges repel each other while conductors.
opposite charges attract each other. Human body and Earth act like a
• Charge is a scalar quantity and its SI unit is conductor. Silver is the best
coulombC. conductor.
• Electricity is associated with the charge. Insulators are those substance
• The proton possesses positive charge (+e) which do not allow passage of charge
and electron possesses an equal negative through themselves. Rubber, wvood,
charge (e), mica, glass, ebonite are insulators.
GENERAL KNOWLEDGE ~ General Science 371

Coulomb's Law ELECTRICAL CAPACITY

The force of attraction or the force of • When a conductor given a charge, its
repulsion acting between the two point potential rises in proportion to the charge
charges is proportional to the product of the given, the constant of proportionality is
magnitudes of the two charges and inversely called capacitance (C) ie. C=2
proportional to the square of the distance
between them. • Its SI unit is coulomb (C)/volt (V called
ie. Fæl992 Farad (F) For capacitances C,Co, C3....are
4
2
TEnr in parallel, equivalent capacitance is given
by C=C +Cgt.....C,

e
For capacitances in series
Electric Field
• The region around an electric charge 1_41t...

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in which the electric efect can be
C
experienced is called the electric field. Potentiometer is used to measure the
exact potential difference between two
Electric Field Intensity (E) points of an electric circuit or to measure
the electromotive force (emf) of a cell.
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The electric field intensity at any point is
the force experienced by a unit positive
charge placed at that point. Electric Current
• It is amount of charge that flows per second
ie. Electic field intensity (E)
through a cross-sections of conductor.
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where, go is positive test charge Current is scalar quantity. Its unit is

ampere (A).
• Electric field intensity inside a charged
hollow conductor is zero. Ohm's Law
.
Electric Field Lines of Force Electric. It states that the physical conditions
ie

field at a place is pictorially represented (temperature, mechanical strain etc)

by these lines. These originate at remaining unchanged, the current ()
positive charge and terminate at flowing through a conductor is always
jm

negative charge. directly proportional to the potential

difference. (V) across its two ends.
Electric Potential i.e. Io V
• Electric potential at any point of the
electric field can be measured by the wherp Ris a constant V= IR
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called resistance of
amount of work done in bringing a unit
circuit.
positive charge from infinity to that
point.
• Its unit is volt and it is a scalar quantity.
. • SI unit is ohm (2).
The electric potential inside
spherical surface is same at each point
and is equal to the potential on the Resistance
Surface. • The ability of material to oppose the
• Electrical potential Earth is electric current through it, is known as its
considered to be zero. electrical resistance.
a
• Work done in bringing a unit positive The resistance
of
conductor is directly
charge from one point to other point is proportional to its length and inversely
proportional to its cross-sectional area (A),
the potential difference between the
two points. ie. Ro
• The work done
in moving charge on A
equipotential surface is zero, because where, p is the resistivity of material.
potential remains same throughout the On increasing the temperature of the
surface. metal, its resistance increases.
 372 GENERAL KNOWLEDGE~ General Science
• On increasing the temperature of
conductor, its resistance
Important Points
semi-
decreases. -A lightning conductor is fixed to tall building to
• protect them from the distructive effect of the
On increasing the temperature of lightning.
electroltes, their resistance The filament of an electric bulb is made of
decreases. tungston because it has a high melting point and
• For resistances in series can be heated to a high temperature to emit light.
An electric bulb makes a bang when it is broken
•
R=R +Rt..... R,
because there is a vacuum inside the electric
For resistances in parallel
bulb, when the bulb is broken air rushes in at
1_1,1 great speed from all sides to fill the vacuum. The
rushing of air produces a noise generally referred

e
to as the bang.
Resistivity

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•
Specific resistance or resistivity Electric Power
depends only on the material of It is the electric work done by the electric
conductor and its temperature.
Resistivity increases with temperature.
• Resistivity of a
instruments per unit time, i.e.P
ra t
Its =.
conductor change unit is watt.
with impurity.
. Resistivity of an alloy greater Kilowatt Hour (kWH)
is than the . It is the unit of energy and is equal to the
resistivity of its constituents. energy consumed in the rate of 1 kilowatt
• If a vire is stretched or doubled on
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(1000 J/s) for 1 hour:.

itself, its resistance willchange, but its . lkilowatt hour =3.6 x 10 joule
specific resistance will remain
unaffected. Electric Fuse
• It is a small conducting wire of alloy of
ie

Galvanometer copper, tin and lead having low melting

• It is a device used to detect and
measure electric current in a circuit. • point aand high resistance.
It is protective device used in series to
It can measure current up to 10°A.
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prevent the damage due to excess flow of

• A galvanometer can be converted into
current.
a voltmeter by connecting a very high AII electric appliances like bulbs, fans etc
resistance in its series. are connected in parallel across the live
Note Shunt is a low resistor connected in wires and the neutral wires.
@

parallel with a cirCuit or device that

reduces the amount of electric Electric Cell
current tlowing thrugh it. •
Electrical cell is a device which converts
Ammeter chemical energy into electrical energy.
It is a device which is used to Electrical Cells are basically of two types
measure electric current in a circuit. ) Primary cell (i) Secondary cell
• It is connected in series in the circuit. Primary Cell
• The resistance of arn ideal ammeter is In primary cell electrical energy is obtained
zero. from the irreversible chemical reaction
Voltmeter taking place inside the cell. After complete
discharge, primary cell becomes
• It is a device used to measure the Lunserviceable.
potential difference between two •e.g. Voltaic cell, Leclanche cell, Daniel
points in a circuit. cel, Dry cell etc.
.
It is connected in parallel in the
Secondary Cell
circuit.
• The resistance of an ideal voltmeter is
• Secondary cells can be charged again and
again. Acid and alkali accumulators are the
infinite. types of secondary cells.
GENERAL KNOWLEDGE ~ General Science 373

on it is called magnetie field. The unit of

TRANSFORMER magnetic field is newton/ampere- metre or
• Transformer is a device which converts weber/ metre or tesla.
low voltage AC into high voltage AC and • Magnetic lines of force are imaginary
high voltage AC into low voltage AC. It is
based on electromagnetic induction. lines in the magnetic field, which shows
the direction of magnetic field
• Microphone converts sound energy continuously.
into electrical energy and works on the •
principle of electromagnetic induction. The magnetic lines of force outside the
magnet always travel from North pole to
• DC motor is a device which converts
South pole and inside the magnet from
electrical energy into mechanical energ,.
South pole to North pole.

e
Step-up ransformer converts a low voltage
of high current into a high voltage of low Characteristics of Substance
Current. Step-down transfomer converts

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Diamagnetic Bismuth, zinc, copper, silver,
a high voltage of low current into a low Substance gold, diamond, mercury, etc.
voltage of high current. Alurminium, platinum,
Paramagnetic
Substance manganese, sodium, oxygen
AC Dynamo (or generator) is a device used etc.
ra
to convert mechanical energy into electrical
Ferromagnetic Iron, cobalt, nickel, ferric
energy. It works on the principle of ohloride etc.
Substance
electro-magnetic induction.
Permanent Magnet
nt

MAGNETS
. The material They are made of steel and temporary
which can attract the magnet or electromagnets are made of soft
magnetic substances (such as cobalt. iron.
iron and nickel) is called a magnet and The soft iron can be magnetised or
ie

the property of attracting the magnetic demagnetised easily.

substance by a magnet is called
magnetism. Curie Temperature
jm

• The magnets which do not lose

their • As temperature increases, the magnetic
magnetism with normal treatment are property of ferromagnetic substance
called permanent magnets. decreases and above certain
. temperature the substance changes into
The materials which retain their
magnetism for a long time are called paramagnetic substances. This
@

hard magnetic materials. When a temperature is called Curie temperature.

magnet is freely suspended, it aligns • For soft iron, Curie temperature is
itself in the geographical North-South 1000 K.
direction. • Magnetic
Flux (o,) The number of
• The permanent magnets are made of
magnetic lines of force crossing a surface
certain alloys of nickel, cobalt and alloys normally
of iron with some carbon. They are made
in various shapes such as bar, rod, disc,
ring etC. where, B is magnetic field strength and A
is area normal to the field lines. Its SI
• When poles of Lwo magnets are brought
unit is weber.
close together, they exert force on each • Electromagnetic
Induction The rate of
other. change of magnetic flux through a coil is
• Similar poles repel each
other and called induced emf.
dissimilar poles attract each other. .
The direction of induced emf will be
• The area surrounding the magnet in
such that it opposes the cause.
which, another magnet experience a force
374 GENERAL KNOWLEDGE~General Science

Atomic and Nuclear Physics

Cathode Rays • X-rays produce illumination on
on
• Cathode rays are the stream of high speed falling fluorscent substances.
negatively charged particles moving from X-rays ionise the gas through which
cathode to anode in a discharge tube. they pass.
• Cathode rays are used in cathode ray • X-rays penetrate through different
oscilloscope and in production of X-rays. depth into different substances.
• X-rays shows photoelectric effect.
Properties of Cathode Rays

e
• X-rays are used in surgery, radio
1. Cathode rays travel in straight lines. therapy, engineering department and
2. Cathode rays can ionise the gases.

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searching.
3. Cathode rays can produce X-rays. •
The intensity and the penetrating
4. Cathode rays can produce fluorescence. power of X-rays can be controlled
5. Cathode rays can penetrate through thin independently.
metal foils
ra Photoelectric Effect
6. Cathode rays are deflected in magnetic
field. The phenomenon of emission of
7. Cathode rays are deflected in electric field. a
electrons from metal surface when
light of appropriate frequency is
Anode Rays or Positive
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incident on it, is called photoelectric

Rays or Canal Rays effect. The electrons emitted during
• Positive rays are moving positive ions of the photoelectric Current, are called
gas filled in the discharge tube. The mass of photoelectrons.
ie

these particles is nearly equal to the mass of Applications of

the atoms of gas.
Photoelectric Cells
Properties of Positive Rays
jm

• In reproduction of sound in cinema,

•
These rays travels in straight line. television and photo telegraphy.
• To control the temperature in
These consists of fast moving positively
charged particle. furnace and in chemical processes.
•
These rays are deflected in magnetic feld n automatic doors.
@

and electric field. •

In photoelectric counters.
• Speed of positive rays is less than that of • In automatic switches for street
cathode rays. These rays can affect the lights.
photographic plate. • In photoelectric sorters.
•
These rays penetrate through the thin
aluminium foil. Photoelectric Cell
•
These rays can produce fluorescence and • It is a device based on phenomena of
phosphorescence. photoelectric efect which converts
light energy directly into electric energy.
X-Rays • Photoelectric effect is based on the
These rays were discovered by Roentgen. law of conservation of energy.
These rays are electromagnetic in nature.
Properties ofX-Rays
Fluorescence and
• X-rays travels in straight line.
Phosphorescence
• Speed of X-rays is equal to speed of lioht Fluorescence is the phenomena of
These are not deflected by electric and emission of light of low frequency
magnetic fields. from a substance when some light
from a source is incident on it.
GENERAL KNOWLEDGE ~ General Science 375
• While in phosphorescence the substance can •
Nuclear Fission The process of
emit light for some time even after the source is the splitting of a heavy nucleus
removed. into two or more lighter nucleus
• Zinc sulphide exhibit the phenomena of is called nuclear Fission.
phosphorescence. •
Nuclear Fusion The process of
combining of two lighter nucleus
to form one heavy nucleus, is
RADIOACTIVITY called nuclear fusion. Hydrogen
• Henry Becquerel, Madame Curie and Pierre bomb is based on nuclear fusion
Curie discovered the phenomenon of and it is more destructive than an
radioactivity in 1896 and for this they jointly atom bomb.
Noble prize.The rays emitted by

e
wOn
radioactivity Were first recognized by Mass-Energy Relation
Rutherford. • Albert Einstein establised a

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• Radioactivity is a nuclear phenomenon. It is relation between I1ass and
spontaneous emission of radiation from the energy on the basis of special
nucleus. theory of relativity in 1905.
• The nucleus having protons 83 or more are According to this mass can be
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unstable. They emit o, B particles and y rays to converted into energy and
become stable. The elements of such nucleus vice-versa.mc
are called radioactive elements and the i.e. E =
phenomenon of emission of a, B particles and Y where, c is the velocity of light
rays is called radioactivity. and E is the energy equivalent of
nt

• The penetrating power for d-particle is Imass m.

minimum and for Y-rays is maximum.
Important Points
SEMICONDUCTOR
ie

•
The substance in which electric
The effect on the mass number and atomic number with conduction is not possible at a low
the emission of o., B and Y rays is decided by temperature but on increasing the
Soddy-Fajan law. Radioactivity is detected by temperature, electric conduction
jm

cOunter. becomes possible are called the

When a radioactive atom emits one d-particle then semiconductor.
atomic number of resultant atom decreases by 2 unit At absolute Zelo kelvin,
and mass number decreases by 4 unit. semiconductor behaves like a
@

When a radioactive atom emits one B-particle then perfect insulator.

atomic number of resultant atom increases by 1 unit The electrical conductivity of a
and masS number remains same. semiconductor increases with
When a radioactive atom emits y-rays the mass the increase in temperature.
number and atomic number remain unchanged. Germmanium and silicon are two
Half-life of a radioactive material cannot be changed important semiconductors.
by physical or chemical processes. The percentage of A pure semiconductor is called
atoms left after one mean life time is equal to 37%. intrinsic semiconductor and to
Radioactive carbon-14 is used to measure the age increase its conductivity a
of fossils and plants. In radio carbon dating age is chemical process is performed
decided by measuring the ratio of gC12 and gc. on it which is called doping.

•
In pure semiconductors,
Madame Curie and her husband Pierre Curie impurity must be less than in
1

discovered a new radioactive element radium 108 parts

of semiconductor.
and found that an ore of uranium is much more An impure semiconductor is
radioactive than the pure Uranium. The end
product of all natural radioactive element after called extrinsic semiconductor.
These ae of two types
emission of radioactive rays is lead. 1. =type 2. p-type
376 GENERAL KNOWLEDGE~ General Science

n-type Semiconductor TRANSISTOR

• If pentavalent impurity atom (such as It is a combination of two p-njunctionsjoined
antimony, arsenic, phosphorus etc.) is in series. Transistors are of two types : -p-n
added to the pure germanium or silicon junction transistor and p-bp junction
crystal, the crystal so obtained is called transistor
the -type semiconductor. Triode valve can be used as amplifier,
• Pentavalent impurities are called donor. oscillator, transImitter and detector.
p-type Semiconductor Air bubble rises up in water because of
• If trivalent impurity atom (such as upthrust and its potential energy decreases.
aluminium, boron, gallium etc.) is When two protons are brought towards

e
added to the pure germanium or silicon each other they repel each other being similar
Crystal, the crystal so obtained is called charges, thus work is done us in bringing

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P-type semiconductor. them close. So, potential energy increases.
.
Trivalent impurities are called accepter. When the energy of the satellite is
negative, it moves in either a circular or an
p-n Junction elliptical orbit. When the energy of satellite
• An arrangement consisting a p-type is zero, it escapes away from its ortbit and its
ra
semiconductor brought into a close path becomes parabolic.
contact with -type semiconductor, is When the energy of a satellite is positive,
called a p-njunction. it escapes from the orbit following a
.
Rectifier is a device which converts hyperbolic path. When the height of the
nt

alternating voltage into direct voltage or satellite is increased, its potential energy
Current. Diode valve acts a rectifier. increases and kinetic energy decreases.
• LEDs are specially designed diode
made of GaAs GaP and are used in
ie

•
electronic gadgets as indicator light. NANOTECHNOLOGY
. Nanotechnology
Zener diode is a highly doped p-n js the study of
junction diode which is not damaged by manipulating matter on an atomic and
jm

high reverse cUrrent. molecular scale. Generally nanotechnology

deals with strcutures sized between 1 to
Noble Prize 100 nanometre in at least one dimension,
• 2016 The Noble Prize in Physics 2016
and involves developing materials or
was awarded to David J. Thouless, E
@

devices within that size.

Duncan, M. Haldane and J. Michael The term nanotechnology was defined by
Kosterlitz for "theoretical discoveries Tokyo University of Science Professor
of topological phase transitions and Norio Taniguchi in a 1974 paper as
topological phases of matter." follows: "Nanotechnology mainly consists
These theoretical discoveries revealed of the processing, separation,
the possibility of a bizarre world where consolidation, and deformation of
matter can take on different and strange one atom or one
stages. materials by by
• 2015 The Nobel prize is Physics 2015
molecule."
• Molecular nanotechnology sometimes
was jointly awarded to Takaaki Kajita
called molecular manufacturing,
and Arthur B. MC.Donald "for the describes engineered nanosystems
discovery of neutrino oscillations,
(nanoscale machines) operating on the
which shows that neutrinos have mass" molecular scale. Molecular
• 2014 The Noble prize in Physics 2014
nanotechnology is especially associated
was awarded jointly to Isamu Akasaki, with the molecular assembler, a machine
Hiroshi Amano and Shiji Nakamura, that can produce a desired structure or
for inventing a new energy efficient device atom-by-atom using the principles
and environment friendly light source of mechnosynthesis.
the blue Light Emitting Diode (LED).
GENERAL KNOWLEDGE ~ General Science 377

• Spintronics a technology that exploits the intrinsic spin of the electron and it
associated with magnetic with moment, in addition to its fundamental electronic
charge, in solid-state devices.
• Diamondoids Non-scale molecules with characteristic diamond structure isolated from
petroleum.
• Grey Goo is hypothetical end-of-the-world scenario involving molecular
nanotechnology in which out of control self- replicating robots consume all matter on
earth, while building more of themselves.
• Carbon nanotubes and nanofibers are molecular-scale tubes of graphitic carbon with
outstanding properties.
• Nano computing is the techique of computing by using the various nano

e
components.
Units of Measurement

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Quantily Unit (SI) Quantity Unit (S)
Volume Cubic Tmetre Heat Joule
Acceleration Metre/second Absolutetemperature Kelvin
Density Kilograr/metre
ra Resistance Ohm
Momentum Kilogram metre/second Electromotive force Volt
Work Joule Electrical conductivity Mho/metre
Energy Joule Electric energy Kilo wat hour
nt

PresSure Pascal or Newton/melre Electric power Kilo watt or watt

Freguency Hertz Magnetic intensity Orsted
Power Watt Charge Coulomb
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Weight Newton or Kilogram Magnetic indUction Gauss

Impulse Newton-second Intensity of sound Decibel
Angular velocity Radian /second Power of lens Dioptre
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Viscosity Poise Depth of sea Fathom

Surface tension Nevton/metre

Important Laws/Theories and their Scientist

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Laws/Theories Soierntist
Gravitational Law, Laws of Motion Newton
Theory of Relativity A. Einslein
Discovery of X-ray WC Rontgen
Principle of Lever, Relalive Density Archimedes
Kinetic Theory of Termperature Kelvin
Theory of an Atom Dalton
Laws of Electrolysis M Faraday

Important Scientific Instruments

Instrument Use
Altimeler It measures altitudes and is used in aircrafts.
Ammeter It measures strength of electric current (in ampere).
Audiomeler It measures intensity of sOund.
Baromeler It measures almOspheric pressure.
Binocular It is used to view distant objects.
378 GENERAL KNOWLEDGE~ General Science

Instrument Use
Calorimeler It measUres quantity of heat.
Cardiogram It traces movements of the heart, recorded on a cardiograph.

Chronomeler It delermines longitude of a place kept on board ship.

Cinematography It is an instrument used in inema making.

Dynamo It converts mechanical energy into electrical energy.

Dynamometer It measures electrical power.

Electrometer It measures electricity

Electroscope It detects presence of an electric charge.

e
Endoscope It examines internal parts of the body.

Fathometer It measures the depth of the ocean.

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Galvanometer It measures the electric Ourrent of low magnilude.

Hydrometer It measures the specific gravity of liquids.

Hygrometer It measures humidity in air.

Hydrophone It measures sound under water.

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Lactometer It deterTines the purity of milk.
Manometer It measures the pressure of gases.

Mariner's compass It is an instrument used by the sailors to determine the direction.

Microphone Itconverts the sOund waves into electrical vibralions.

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MicrOscope It is used to obtain magnified view of small objects.

Odometer It is an instrument by which the dislanoe covered by wheeled vehicles
is measured.
ie

Phonograph It is an instrument for producing sund.

Photometer This instrument compares the luminous intensity of the source of light.
Periscope It is used to view objects above sea level (used in sub-marines).
jm

Radar It is used for delecting the direction and range of an approaching

plane by means of radio microwaves.
Radiometer It measures the emission of radiant energy

Seismograph It measures the intensity of earthquake shocks.

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Salinomeler It delerrnines salinity of solution.

Spectrometer It is an instrument for measuring the energy distribution ofa particular

type of radiation.
Speedometer It is an inslrument placed in a vehicle to record ils speed.
Sphygmomanomeler It measures blood pressure.
Spherometer It measures the ourvalures of surfaces.
Stereoscope It is used to view two dimensional pictures.
Stethoscope An instrument which is used by the doctors to hear and analyse heart
and lung sounds.
Stroboscope It is used to view rapidly moving objects.
Tachometer An instrument used in measuring speeds of aeroplanes and motor
boals.
Telescope It views distant objects in space.
Thermometer This instrument is used for the measurement of temperatures.
Thernostat It regulates the temperature at a particular point.

Voltmeter It measUres the electric potential difference between two points.

GENERAL KNOWLEDGE~General Science 379

Inventions and Discoveries

Invention Year Inventor Country
Adding machine 1642 Pascal France
Aeroplane 1903 Orville & Wilbur Wright USA
Air conditioning 1902 Carrier USA
Airplane (Jet engine) 1939 Ohain Gerrnany
Airship (Non-rigic) 1852 Henri Gifard France
Atornic bomb 1945 J Robert Oppenheimer USA
Ball-point pen John J Loud USA

e
1888
Barometer 1644 Evangelista Torricelli Italy

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Battery (Electric) 1800 Alessandro Volta Italy
Bicycle 1839-40 Kirkpatriok Maomillan Britain
Bicycletyres (Pneumatic) 1888 John Boyd Dunlop Britain
Bifocal lens 1780 Benjamin Franklin USA
Bleaching powder
ra Tennant Britain
1798
Bunsen burmer 1855 R Willhelm von Bunsen Germany
Burglar alarm 1858 Edwin T Holmes USA
Camera (Kodak) 1888 Walker Eastman USA
nt

Car (Steam) 1769 Nicolas Cugnot France

Car (Petrol) Karl Benz Germany
1888
Carburetor 1876 Gotlieb Daimler Gerrmany
ie

Cassette (Videotape) 1969 Sony Japan

Cerment (Portland) 1824 Joseph Aspdin Britain
Cinema 1895 Nicolas & Jean Lumiere France
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Clock (Mechanical) 1725 &

-Hsing Liang Ling-Tsan China
Clock(Pendulum) 1656 Christian Huygens Netherlands
Compact disc 1972 ACA USA
@

Compact disc player 1979 Sony, Philips Japan,

Netherlands
Computer (Laptop) 1987 Sinclair Britain
Computer (Mini) 1960 Digital Corp USA
Diesel engine 1895 Rudolf Diesel Germany
Dynamo 1832 Hypolite Pixi France
Electric flat iron 1882 HW Seeley USA
Electric lamp 1879 Thomas Alva Edison USA
Electric motor (DC) 1873 Zenobe Gramme Belgium
Electric motor (AC) 1888 Nikola Tesla USA
Electric iron 1882 Henry W Seely USA
Electric washingmachine 1906 Alva JFisher USA
ElectrO-magnet 1824 William Sturgeon Britain
Electron 1897 Thomson J Britain
Electroplating 1805 Luigi Brugnatelli Italy
Electronic computer 1824 Dr Alan M Turing Britain
380 GENERAL KNOWLEDGE~ General Science

Invention Year Inventor Country

Facsimile machine 1843 Alexander Bain Britain
Fibre optics 1955 Kepany Britain
Film (Moving outlines) 1885 Louis Prince France
Film (Talking) 1922 J Engl, J Mussolle & H Vogt Germany
Galvanometer 1834 Andre-Marie Arpere France
Gramophone 1878 Thomos Alva Edison USA
Helicopter 1924 Etienne Oehmichen France
Hydrogen bomb 1952 Edward Teller USA

e
Intelligence testing 1905 Simon Binet France
Jet engine Sir Frank Whittle Britain

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1937
Laser 1960 Theodore Maiman USA
Launderette 1934 JF Cantrell USA
Lift
(Mechanical) 1852 Elisha G Otis USA
Lighting conductor
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1752 Benjarnin Franklin USA
Loudspeaker 1900 Horace Short Britain
Machine gun 1918 Richard Gatling Britain
Magnetic recording tape 1928 Fritz Pleumer Germany
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Microphone 1876 Alexander Graham Bell USA

Microscope (Comp.) 1590 Z Janssen Netherlands
Microscope (Elect.) 1931 Ruska Knoll Germany
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MicrOwave oven 1947 Percy LeBaron Spencer USA

Motor cycle 1885 G Daimler Germany
Movie projector USA
1893 Thomas Edison
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Neon lamp 1910 Georges Claude France

Neutron bornb 1958 Samuel Cohen USA
Optical fibre 1955 Narinder Kapany Germany
Pacemaker 1952 Zoll USA
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Photoelectric cell 1893 Julius Elster, Hans F Geitel Germany

Photography (On metal) 1826 JN Niepce France
Photography (On paper) 1835 WH Fox Talbot Britain
Photography (On film) 1888 John Carbutt USA
Piano 1709 Cristofori ltaly
Pistol, revolver 1836 Colt USA
Radar 1922 AH Taylor & Leo C Young USA
Radiocarbon dating 1947 Libby USA
Radio telegraphy 1864 Dr Mohlon Loomis USA
Radio telegraphy (Trans 1901 G Marconi Italy
Ailantic)
Rayon 1883 Sir Joseph Swan Britain
Razor (Electric) 1931 Col Jacob Schick USA
Razor (Safety) 1895 King C Gillette USA
Refrigerator 1850 James Harrison, Alexander USA
catlin
GENERAL KNOWLEDGE ~ General Science 381

Invention Year Inventor Country

Rubber (Latex foam) 1928 Dunlop Rubber Co Britain
Rubber (Tyres) 1846 Thomas Hancock Britain
Rubber (Vulcanised) 1841 Charles Goodyear USA
Rubber (Waterproof) 1823 Charles Macintosh Britain
Safety pin 1849 Walter Hunt USA
Ship (Stearn) 1775 ICPerier France
- Ship (Turbine)
1894 Hon Sir C Parsons Britain
Steam engine Thomas Savery

e
1698 Britain
Steam engine (Piston) 1712 Thomas Newcomen Britain

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Steam engine (Condenser) 1765 Jarmes Watt Britain
(Stainless)
Steel Harry Brearley Britain
1913
Stethoscope 1819 Laennec France
Submarine 1776 David Bushnell USA
Super computer
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1976 JH Van Tassel USA
Tank 1914 Sir Ermest D Swington Britain
Tape recorder 1899 Fessenden Poulsen Denmark
Telegraph 1787 M Lammond France
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Telegraph code 1837 Sarmuel FB Morse USA

Telephone (Cellular) 1947 Bell Labs USA
Telephone (Imperfect) 1849 Antonio Meucci Italy
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Telephone (Perlected) 1876 Alexander Graham Bell USA

Telescope 1608 Hans Lippershey Netherlands
Television(Mechanical) 1926 John Logie Baird Britain
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Television (Electronic) 1927 PT Farnsworth USA

Television (Colour) 1928 John Logie Baird Britain
Transformer 1831 Michael Faraday Britain
Transistor USA
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1948 Bardeen, Shockley & Brattain

Transistor radio 1955 Sony Japan
Uranium Fission (Atomic 1942 Szilard Fermi USA
reactor)
Vacuum cleaner (Elec.) 1907 Spangler USA
Video tape 1956 Charles Ginsberg USA
Washing machine (Elec.) 1907 Hurley Mlachine Co USA
Watoh 1462 Bartholomew Manfredi Italy
Wireless (Telegraphy) 1896 G Marconi Italy
 CHEMISTRY
MATTER AND Boiling Point
ITS STATES • It is a temperature at which vapour
pressure of a liquid becomes equal to
MATTER atmospheric pressure and at which a
substance converts from its liquid state
• Matter is anything which has mass and to gaseous state.
occupies space. • It is different at different places.

e
• It exists in five states, viz, solid, liquid,• Boiling point of water at nomal
gas, plasma and Bose-Einstein conditions is 100° C
condensate. Out of which the former .

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It usually decreases at high altitudes,
three are commonly seen. that's why, at high altitudes, the boiling
point of water is less than 100°C and
States of Matter more time is required to cook a food.
The five states ofmatter are discussed below • Boiling point of water in pressure cooker
ra
is high due to high pressure and hence,
Solids less time is required to cook the food.
• They have defânite volume and definite • Boiling point increases in the presence
shape. of impurity.
nt

• They are incompressible and have

strongest intermolecular interactions. Evaporation
• They are very dense as compared to liquid It is the process of conversion of a liquid
and gas. e.g., wood, stone, iron, etc. into vapours at any temperature below
ie

its boiling point. It increases with

Melting Point increase in surface area and
• It is a temperature at which a substance temperature.
converts from its solid state to liquid .
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It produces cooling. That's why we feel

state. Melting point of ice is 0° C. cool when some nail polish remover or
• Melting point decreases in the presence spirit is kept on our palm.
of impurity.
Gases
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Sublimation • They have neither definite volume nor

• It is the process of conversion of a definite shape. They take the shape and
substance from the solid state to the gas volume of the container in which they
state without passing through an are filled.
intermediate liquid phase. They are highly compressible.
• It is used to separate a sublimate • They can flow so considered as fluids,
(substance undergoing sublimation like e.g., air, oxygen and nitrogen.
camphor, naphthalene, ammonium
chloride, etc) from non-sublimate. Condensation
• It is the process of conversion of gas into
.Liquids
They have definite volume but no definite
liquid or liquid into solid
Solids. liguids and gases are inter
shape. They take the shape of the vessel convertible by changing the conditions
in which they are kept. of temperature and pressure.
• They can flow, hence, considered as heat heat
fluids e.g., milk, water, mercury etc. SolidLiquid: Gas
Cool
 GENERAL KNOWLEDGE~General Science 383

Plasma • Examples of elements are sulphur,

• phosphorus, oxygen etc.
The fourth state of matter is called
plasma. This state contains jonised gas Elements known at present are 118. Out
with super energetic and super excited of which 94 are natural. Elements which
particles.
are liquid at room temperature are
. mercury (Hg) and bromine (Br).
Fluorescent tube contains helium (He)
gas and neon (Ne) gas. Sign bulb Elements which become liquid at a
temperature slightly above the room
contains neon (Ne) gas. temperature (303 K) are gallium (Ga) and
Bose-Einstein Condensate caesium (Cs).
• In 1924-25, Satyendra Nath Bose and Elements have the following order of

e
Albert Einstein gave the information abundance in earth crust : Oxygen >
about Bose-Einstein condensate. It is a silicon > aluminium > ion > calcium.
.

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state of matter of a dilute gas of boson Elements have the following order of
cooled up to temperature which is very abundance in human body : Oxygen >
close to absolute zero or -273.15°C. In carbon > hydrogen > nitrogen.
fact, it is a fifth state of matter.
Compounds
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Particles of Matter •
These contain more than one kind of
atoms. These cannot be separated into
Atoms constituent atoms by simple physical
• It is the smallest particle of matter that methods.
nt

takes part in chemical reactions. • Their examples are silica (Si02), water
(by Dalton's atomic theory). (H,0), sugar (C;H0,), salt (NaCl), etc.
• It can neither be created nor destroyed
(law of conservation of mass given by Impure Substances
ie

Lavoisier). A substance is said to be impure, if all the

• It does not exist in free state and has a constituent particles of that substance are
fixed atomic mass e.g., iron (Fe), gold not same in their chemical nature.
jm

(Au), silver (Ag), etc.

Mixtures
Molecules •
These are obtained by mixing two Or more
•
These are the smallest part of the substances in any proportion.
matter that exist in free state. • Mixtures can be homogeneous, i. e., have ,
@

g.
• They are formed by the joining of two or uniform composition throughout (e. salt
more atoms in fixed ratio (law of solution, Sugar solution, air. true
multiple proportions given by Dalton). solutions, etc) or heterogeneous, i. e., have
• They have fixed molecular mass which non-uniform composition (e.g., mixture of
is obtained by adding the atomic masses salt and sugar, colloidal solutions, etc).
of all the atoms present in a molecule,
e.g., water (H,0), ammonia (NH),
Solutions or True Solutions
carbon dioxide (CO), etc. These are homogeneous mixtures of two
or more substances.
Pure Substances •A solution contain two components :
A substance is said to be pure if all the solute (in less quantity) and solvent (in
more quantity). Examples of solutions are
constituent particles of that substance are
the same in their chemical nature. e.g., sugar solution, tincture of iodine
all the elements and compounds are pure (solution of iodine in alcohol), aerated
substances. drinks like soda water, air, alloys, etc.
• Concentration of solution may be
Elements expressed by percentage, mole fraction,
• They contain only single type of atoms. parts per million, gram per litre, molarity
Elements combine to give molecules. molality, normality, etc.
384 GENERAL KNOWLEDGE~ General Science

Colloidal Solutions Separation of Mixtures

• are heterogeneous mixtures.
. These
A number of physical and chemical
These contain two phases, i.e., dispersed methods are used to separate the number
phase and dispersion medium. of mixtures. Some important methods are
belouU
•
These can scatter light because of the discussed
presence of large solute particles, i.e.,
Centrifugation
they show Tyndall effect and Brownian •
movement. It is based upon the principle that the
•
Blue colour of sky is also due to denser particles are forced to the bottom
scattering of light by dust particles and the ighter particles stay at the top
when spun rapidly.

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Suspended in air.
• They are separated by special technigue t is used in diagnostic laboratories for
like centrifugation. blood and urine tests, in dairies and

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• Colloidal solutions are coagulated by home to separate butter from cream, in
washing machine to squeeze out water
adding an electrolyte. from wet clothes, etc.
• Colloidal solutions are purified by
dialysis, which is also used in the Distillation
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purification of blood with the help of It is a method of separating mixtures
artificial kidney machine. based on differences in volatilities
• Coagulation found its Use of components in a boiling liquid
purification of water by alum, stop mixture.
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bleeding by FeCl a, formation of delta at • It is used to separate mixtures of ether

the junction of sea and river. and toluene, benzene and aniline, etc.
• They are of following types on
the basis
of dispersed phase and dispersion Fractional Distillation
ie

medium. • It is used to separate liquids having very

Dispersed Dispersion Type of Examples less difference in their boiling points.

phase medium colloid It is used to obtain pure diesel, petrol,
kerosene oil, coaltar, etc from crude oilor
jm

Liquid Gas Aerosol Fog, clouds,

mist mineral oil.
• It is used to separate a mixture of
Solid Gas Aerosol Smoke,
automobile acetone (329 K) and methyl alcohol
exhaust (338 K).
@

Gas Liquid Foam Shaving

Cream
Vacuum Distillation
Liquid Liquid Emulsion Milk,
• It is also knowvn as distillation under
face-crean. reduced pressure.
Solid Liquid Sol Milk of It is used for the substances which
magnesia, decomposes below their boiling point.
MUd
It is used to obtain glycerol and H,0, and
Gas Solid Foam Foam, to concentrate sugarcane juice in sugar
rubber, industry.
sponge,
pumice Steam Distillation
stone
It is used to separate a steam volatile
Liquid Solid Gel Jelly,
cheese, compound from non-volatile Or
butter non-steam volatile compounds.
Solid Solid Solid Coloured It is used to purify sandalwood oil,
sol gemstone, terpentine oil, aniline, nitrobenzene, etc.
milky glass
 GENERAL KNOWLEDGE~General Science 385)

Crystallisation Number of moles

Mass (in gram)
• It is used to separate a mixture of
inorganic solids with the help of suitable Atomic weight
solvent. (or molecular weight)
•
Their examples include separation of a
mixture of sugar and salt by using GAS LAWVS
ethyl alcohol.
Mass (m), Volume (V), pressure (p) and
Chromatography temperature (T) of a gas are the
• It is the modern technigue Used fr measurable properties. The laws which
gas
separation and purification of organic nter-relate these properties are called

e
compournds. It was discovered by Tswett. laws.
• It is Ised for the separation of coloured Boyle's Law

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pigments from a plant.
At constant temperature, the pressure
Reverse Osmosis of a fixed amount of gas (number of
• It is a technique in which solvent moles) is inversely proportional to its
volume.
molecules move from the solution of
ra
higher concentration to the solution of The mathematical equation is
lower concentration when these are p or pV=k or p,-PV
separated by semipermeable membrane
and excess pressure is applied to the p=Pressure of the gas,
nt

solution of higher concentration. V=Volume of the gas,

• It is used for desalination of sea water. k=Constant
Physical Change Charles' Law
ie

• It is the change which only affect the At constant pressure, volume of a fixed
physical properties like colour, hardness, mass ofa gas is directly proportional to
density, melting point, etc., of matter. its absolute temperature.
• It does not affect the composition and
jm

This law can be written as V T

chemical properties of matter. where, Vis the volume of the gas,
• Examples of physical changes are Tis the absolute temperature.
crystallisation, sublimation, boiling,
vaporisation, cutting of trees, dissolving Gavy Lussac's law
@

common sugar in water, etc.

At constant volume, pressure of a fixed
Chemical Change amount of a gas varies directly with
as temperature, i.e. px Tor Kor
P- 2
•
These affect the composition as well T
chemical properties of matter and result
a new substance. (K = constant).
. in the formation of
Their examples are burning of fuel,
burning of candle, electrolysis of water
Combined Gas Law
burning of paper, photosynthesis, OT ldeal Gas Equation
ripening of fruits, etc. It is a gas law which combines
Charles' law, Boyle's law and
Mole Concept Gay-Lussac's law.
It states that the number of molecules This law can be stated mathematically
present in 12 g of C-12 is called one mole, as,
i.e., 1 mnol = 6.023 x 1023
= Avogadro's number (NA) p=R: pV= RT
T
e.q.. 1 mole of atom = where, R=Universal gas constant
=gram atomic weight For n moles of the gas, pV = nRT
=6.023 x 102 atoms
386) GENERAL KNOWLEDGE ~ General Science

Avogadro's Law ATOMICSTRUCTURE

It states that equal volumes of all gases at
•
the same temperature and
pressure Modern Atomic Theorv
contains the equal number of molecules. According to this theory, 'atom is made up
. of three fundamental particles called
It is stated mathematically as,
electrons, protons and neutrons.
V« n 0r V=kn
V= Volume of the gas, Discovery of Cathode Rays and
n=Number of moles of the gas, Electrons (-e)
.
k=Proportionality constant These rays were discovered by Sir Julius

e
Plucker.
Graham's Law of Diffusion •
These originate from cathode and travels
According to this law, "the rate of diffusion in a straight line towards anode.

nc
of a gas is inversely proportional to the Cathode rays cause mnechanical motion,
square root of its density." i.e., they consists of material particles.
•
These rays carry negative charge and
generate X-rays.
ra
where, ;, is the rate of diffusion for the Electron was discovered by JJ Thomson.
[It's antiparticle is positron (41e").
first gas (volume or number of moles per . It
unit time). has mass 9.1 x 1031 kg or 0.00054 u.
To
is the rate of diffusion for the second • It has charge -l6 x10-19 C (by
nt

gas. Millikan's oil drop experiment).

d, is the density of gas 1.
do is the density of gas 2. Discovery of Anode Rays
M, is the molar mass of gas 1. and Protons ( H'or P)
ie

M, is the molar mass of gas 2. .

These rays were discovered by Goldstein
(also called positive rays).
Dalton's Law of Partial •
These do not originate from anode.
jm

Pressures •
These are positively charged and have
It states that the total pressure exerted by a velocity less than cathode rays.
gaseous mixture of two more •. Proton was discovered by Rutherford.
non-reacting gases is equal to the sum of It is positively charged.
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the partial pressures of each individual . It is present in the nucleus.

component in the gas mnixture. .
It has charge + 1.6 x 10-19 C and mass
Protal P + P2 + ... + Pu
1.672 x 10 kg or l.00727 u.
Ideal and Real Gases • It has mass 1836 times than that of the
• Ideal gases follow gas laws in all electron.
conditions of temperature and pressure.
Discovery of Neutron (on)
• Real gases follow gas laws only at high
temperature and low pressure. • It was discovered by Chadwick.
• It has zero charge and l.674x 102 kg
Critical Temperature or1.00867u mass.
• It is the temperature above which a gas
It js present inside the nucleus. Its
cannot be liquefied. antiparticle is antineutrino.
At STP • Hydrogen is the only atom in which
mm Hg
p=l atm =760 neutrons are not present.
273 K=0°C .
. one Electromagnetic forces bind electrons
Volume of mole of all the gases with the nucleus.
= 22.40L= 22400mL
 GENERAL KNOWLEDGE~General Science 387
• Atoms having same number of electrons Isobars
and protons are neutral. If electrons are
less than proton, the atom carries positive These have the same mass number, but
charge and if electrons are more than different atomic number.
proton, the atom carries negative charge.18Ar"19 K 20 Ca"are isobars.

Discovery of Nucleus Isotones

• The model known as Rutherford's These have same number of neutrons, e.g.,
Model, was based upon d-particle H° and He as both have two neutrons.
scattering experiment and suggests that
most of the part of an aton is empty. Various Models and Theories
• It als0 suggests that the entire mass of

e
an atom is concentrated on its centre at Niels Bohr Model
the nucleus. The nucleus is surrounded This model suggests that the electrons are

nc
by electrons that move around the confined into clearly defined, quantised
nucleus with a very high speed in orbits and could jump between these, but
circular paths called orbits. could not freely spiral inward or outward in
• It contains protons and neutrons which intermediate states.
are collectively called nucleons.
ra
Planck's Quantum Theory
Characteristics of Atom According to this theory
Atomic Number (Z) 1. Atoms and molecules could emit or
absorb energy only in the form of
nt

• It is equal to the
number of protons. discrete packets of energy called quanta.
• It is
equal to the number of electrons in 2. The energy of quantum(E) is
neutral atom. proportional to its frequency (v),
• It is written as a subscript to the left of
e.g., E = hu
ie

the symbol of the atom, e.g., C here 6 where, h=Planck's constant

is the atomic number of carbon (C). (6.626 x 10-31 Js)
Mass Number (A 3. The energy is quantised (multiple of
jm

• It is equal to the sum of nhv)

number of
. protons and number of neutrons. de-Broglie Concept
It is written as a superscript to the right It suggests
that matter possesses dual
of the symbol of the atom, e.g., here nature, i.e., has wave nature as wvell as
C
@

12 is the mass number of carbon (C). particle nature. It also suggests that
wavelength (2) of electron is inversely
Mass number = Number of protons + proportional to its momentum (p) i.e.,
Number of neutrons = Atomic number +
Number of neutrons =Number of electrons + h
Number of neutrons (in case of neutral atom)
where, m = mass of electron
Different Atomic Species and V = velocity of electron

Isotopes
.
Heisenberg's Uncertainty
These have same atomic number but Principle
different mass number. e.g., isotopes of This principle states that it is impossible to
hydrogern e.g., ,H, P (protium), or D H
determine simultaneously the exact position
,
(deuterium) and or
H
T (tritium). T is and exact momentum (velocity) of an
radioactive. electron. It is given as
• Isotopes of polonium are maximum.
• Hydrogen (H-l) is the lightest isotope
Ar- Ap >h 4

and lead-208 is the heaviest isotope Ar is the uncertainty in position

zuhere,
(with mass 207.974). and Apis the uncertainty in momentum.
388 GENERAL KNOWLEDGE~ General Science

Orbits and Subshell Elements Configuration

• According to quantum mechanical *Chromium 2,8, 13, 1 1s.s,2p, 3s,
model. the orbits contain subshell which (2:Cr) 3p, 3d, 4s

in turn contain orbitals. Iron (28Fe) 2,8, 14, 2 1s2,, 2p,3s,

• Four subshells are defined in different
atoms, i.e., s, p, d andf.
*Copper 2,8, 18, 1
1s2, 252, 2p°, 3s2,
• S-subshell
contains One orbital, (23Cu) 4s
3p,3d10
p-subshell contains 3-orbitals, d-subshell
contains 5-orbitals and fsubshell
contains orbitals.
7- Aufbau Principle
orbital can accommodate only (building up, construction)

e
• An

maximum of 2-electrons. • It is used to determine the electronic

configuration of an atom.

nc
The distribution of subshells in different
orbits is as follows • According to it, orbitals are filled in order
Orbits Subshel of their increasing energies, starting with
the orbital of lowest energy. Increasing
order of energies of various orbitals is,
2 p
ra
S, Is < 2s < 2p <3s < 3p < 4s < 3d < 4p
3 S, P, d < 5s < 4d< 5p < 6s<4f < 5d < 6p <7s
4 S, p,d, f < 5f < 6d <7p
S, p, d, f
Hund's Rule of Maximum
nt

S, p, d
7 S, p Multiplicity
It states that if two or more orbitals of equal
The names of these subshells are taken as energy are available, electrons will occupy
ie

including the orbital name with the them singly before filling them in pairs.
subshell name, e.g., the s-subshell of 5th
orbital is termed as 5s, 6d, etc. Quantum Numbers
jm

These show the position and energy of

Electronic
. It is
Configuration electrons in an atom. These aTe four in
the arrangement of electrons in zunbers
various shells, subshells and orbitals in
an atom. Principal Quantum Number, n
.
@

It is written as 2, 8, 8, 18, 18, 32 • It describes the energy of electron and is

always a positive integer (electron shell).
• It is written as ... or 1,
n
(where, n indicates It is represented by K,L, M, N, 2,
the principal quantum number, 3, 4,....
indicates the azimuthal quantum It shows the distance of outer electron
number or subshell and xis the number from the nucleus.
of electrons).
•
Number of electrons in n shell =2,2 Azimuthal Quantum
Number. I
e.g., in second shell the number of It describes the subshells and orbital
=
electrons =2 x2* 8 exceptions of angular momentum of each electron.
normal rule. • It shows
the shapes of orbitals, e.g.
Electronic configuration of some elements S-orbital is spherical, p-orbital is
are tabulated below dumb-bell shape, dorbital is double
Elements Configuration dumb-bell shape and f-orbitals have
complicated structure.
2, 8, 8... nl type • It has values 0 to n -1.
type equal to 0 shows s-orbital, 1 shows
1s2, s2,2p, s'
•I
Sodium 2, 8, 1 p-orbital, 2 shows d-orbital and 3 shows
(,Na) f-orbital.
 GENERAL KNOWLEDGE~General Science 389

Magnetic Quantum Number, m Pauli Exclusion Principle

It shows the orbital of a subshell or It is the quantum mechanical principle
orientation of electron and has values from which states that no two identical
-l to + lincluding zero. fermions (particles with half-integer
spin) may occupy the same quantum
Spin Quantum Number, s state simultaneously.
• It describes the spin of each electron OF
(spin up or spin down). • Only two electrons may exist i the sane
• The value of s can be orbital but these electrons must have
opposite spin.

e
RADIOACTIVITY

nc
• It was discovered by Henry Becquerel but 0ccupy a position one place right to the
term radioactivity was given by Madam parent nuclei in the periodic table
Curie. It is the process of spontaneous (Soddy Fajans group displacement law).
disintegration of nucleus and is
Gamma (y) Rays
measured by Geiger counter.
ra
• It is a nuclear phenomenon, thus These are electromagnetic radiation and
remains unaffected by external factors have very high penetrating power.
like temperature, pressure, etc. •
These have low ionising power and
kinetic energy.
nt

Radioactive Rays • Their emission does not affect the

Radioactivity involves emission of a, B and position of nuclei in the periodic table.
Y rays or particles and has units Curie,
Becquerel, Rutherford. Half-Life Period
ie

Alpha («) Rays It is the time in which a radioactive

substance remains half of its original
•
These rays consist of positively charged amount.
jm

helium nuclei (He+), They have +2 unit

charge and 4 u mass.
Nuclear Fission
• It is a process in which a heavy
nucleus
• They have low penetrating power but is broken down into two or more lighter
very high ionising power and kineic
fragments.
@

energy. •
• An o-emission reduces the atomic mass It is usually accompanied with the
by 4 and atomic number by 2, thus, the emission of neutrons and large amount
new nuclei formed occupy a position two of energy. It is used in nuclear reactor
places left to the parent nuclei in the
and atom bomb.
periodic table (Soddy Fajans group Atom Bomb
displacement law). It is based on uncontrolled nuclear fission.
Beta (B) Rays It contains 235U or 23 Pu as fuel.
•
These rays consist of negatively charged Nuclear Reactor
electrons (Cie) and have -1 unit charge. It is a device that is used to produce
and zero mass. electricity and permits a controlled chain
•
These are more dangerous than 0-rays. nuclear fission.
. • It contains fuels e.g., gp U
moderator
These have high penetrating power as
compared to -rays. (e.g., graphite and heavy water, D,0) to
•A B-emission increased the atomic slow down neutrons and control rods
number by one with no change in atomic (made up of boron steel or cadmium) to
mass, thus, the new nuclei obtained absorb neutrons.
390 GENERAL KNOWLEDGE~ General Science

• It may also contain liquid sodium as Tons

coolant.
These are of two types : cation and anion.
Nuclear Fusion Cations are formed by the loss of electrons
e.g., Nat, Mg2+
• It is a process which involves fusion
oe and carry positive charge,
two or more lighter nuclei to give a Anions are formed by the gain of electrons,
and carrynegative clharge e.g., Ci-, F-, etc.
heavier nuclei.
• It occurs only at extremely high Electrovalent Bond
temperature (>10°K), so also called or
thermonuclear reactions. Ionic Bond
• It is
used in hydrogen bomb. Enerey of It is a type of chemical bond formed

e
Sun is also a result of a series of nuclear through an electrostatic attraction
fusion eactions. between two oppositely charged ions.

nc
• It is formed between a cation, which is
Hydrogen Bomb uSually a metal, and an anion, which is
usually a non-metal, e.g.,
It contains a mixture of deuterium oxide
(D,0) and tritium oxide (T,0) in a space + xCl
XX

surrounding an ordinary atom bomb. Na [Na']L:Ç 1

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Radiocarbon 2 8,1 2 87 sodium chloride
Dating
It is used in deternining the age of carbon lonic Compounds
bearing materials such as wood, animal • They can conduct electricity in molten
nt

fossils, etc. It is based on the concentration or

state in solution, but not in solid state.
of C4 and Cg isotopes. • They have a high melting point and tend
Uranium Dating to be soluble in water. Examples of such
It is used to determine the age of earth, compounds are limestone (CaCO3).
ie

common salt (NaCl), lime (CaO),

minerals and rocks.
magnesium oxide (MgO), etc.
Uses of Radioisotopes •
The energy required to separate the ions
jm

1. lodine-131 is employed to study the of an ionic compound is called lattice

structure and activity of thyroid gland. energy.
It is also used in internal radiation
therapy for the treatment of thyroid
Covalent Bond
• It is a type of chemical bond that is
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disease.
2. Iodine-123 is used in brain imaging. characterised by the sharing of electrons
between two atoms.
3. Cobalt-60 is used in external radiation
therapy for the treatment of cancer.
• It may be a single bond (, formed by
sharing of two electrons i.e., one electron
4. Sodium-24 is injected along with salt from each atom, double bond
solution to trace the flow of blood. (=), fornmed by sharing of four electrons
5. Phosphorus-32 is used for leukemia i.e., two electrons from each atom, or
therapy. triple bond (=), formed by sharing of six
6. Carbon-14 is used to study the kinetics electrons i.e., three electrons from each
of photosynthesis. atom.
•
The geometry of few covalent molecule
CHEMICAL BONDING H,0 (water) - Bent, NH, (ammonia)
•
pyramidal, CH, (methane)-tetrahedral,
It is formed by elements to complete CO, (carbon dioxide) -linear.
eight electrons in their outer shell i.e., to • Single bond contains only 1 -bond;
complete their octet. double bond contains 1 o and l-bond;
• It results in decrease in energy and and triple bond contains lo and
increase in stability. 2-bonds.
 GENERAL KNOWLEDGE~General Science 391

Covalent Compounds van der Waals' Interaction/Force

1. They are non-conductor of The attractive forces among the non-polar
electricity. molecules in solid or liquid states. These are
2. They have low thermal relatively weaker compared to normal chemical
conductivity. bonds.
3. They are insoluble in water, but which can hang on a
The ability of Geckos
soluble in non-polar solvents like glass surface using only one toe-to climb on sheer
benzene, acetone, ether, etc. surfaces has been attributed to the van der Waals'
4. They have low melting and boiling forces between these surfaces and spatulae or
points (diamond and graphite microscopic projections, which cover the hair-like
have very high melting point.)

e
setae found on their footpads.
5. They are directional. So, have
definite geometry.

nc
CHEMICAL REACTION
Coordinate or Dative Bond
• It is a special type of covalent bond
The process in which substances (reactants)
react to form new compounds (products), is
in which both the electrons for known as chemical reaction.
sharing i.e., shared pair of
ra
electrons) are given by only one Types of Chemical Reactions
atom. Chemical reactions are of following types
• Coordinate compounds have
properties in between the ionic and Combination Reactions
nt

covalent compounds. In such reactions, two or more substances

• Examples of coordinate compounds combine to give a single substance, e.g.,
are CaO + H0 Ca(0H),
Water Calcium
ie

Calcium hydroxide
OXide

CN, etc Decomposition Reactions

(Cyanide ion) These are those irreversible reactions in which,
jm

a molecule decomposes into two or more

(Ammonium ion) simpler molecules e.g.,
Hydrogen Bond 2KCIO,
A 2KCI + 302
Potassium Potassium
@

• It is the attractive interaction of a chloride Oxygen

hydrogen chlorate
attached to highly
electronegative atom (such as N, F Dissociation Reactions
O) with another electronegative
atom, such as nitrogen, oxygen or These are those eversible reactions in which a
fluorine. molecule dissociates into two or more simple
molecules, e.g.
• It is stronger (has energy 5 to
30 k]/mol) than a van der Waals' 2HI H, + l,
Hydrogen Hydrogen
interaction. iodide lodine
• It 0CCUrS in both inorganic
molecules such as water and Reversible Reactions
organic molecules such as DNA. Reversible reactions are thse which occurs in
• Ethanol, amine (except 3° amine), forward as well as in backward direction but
etc., can form H-bond with water, never go to completion.
so these are soluble in water
although these are covalent Irreversible Reactions
compounds. Irreversible reactions occur only in forward
direction and go to completion.
 392) GENERAL KNOWLEDGE~ General Science

Displacement Reactions Oxidising Agent or Oxidant

In such reactions, an atom or a group These are the substances that have the ability to
of atoms of a molecule is replaced by oxidise other substances, e.g., H,02, MnO,.
another atom or group of atoms e.g., CrO3. Cr0.
Os0 or elec- tronegative
+
CuSO, Fe FeSO4 + Cu elements (0, F, Cl, Br) etc.
Copper Ferrous
sulphate sulphate
Reducing Agent or Reductant
Double Displacement These are the substances that have the ability to
Reactions reduce other substances, transfer electrons to
another substance; e.g., electropositive element,
These involve exchange of ions metals such as lithium, sodium, magnesium,

e
between two compounds. e.g.,
iron, zinc, and aluminium, hydride transfer
NaCl + AgNO,AgCl + NaNO reagents, such as NaBH, and LiAlH4, etc.

nc
Reactions occurring between the ions Reduclion
or ionic compounds are very fast.
+2 +2 +1 +4
Exothermic Reactions 2HgCh + SnClalag) HgClpls) + SnCl4
(Oxidising (Reducing
These are those reactions in which
ra Agenl) Agent)
energy is released, e.g., burning of
natural gas, respiration, decomposition Oxidalion
of vegetable matter into compost,
combustion reactions etc. Catalysis
nt

• It was discovered by Berzelius.

Endothermic Reactions • It is a term, used for the reactions/ processes
These are those reactions in which which occur in the presence of certain
energy is consumed, e.g., digestion, substances that increase the rate of the
ie

photosynthesis, evoporation of water, reaction without being consumed. Such

melting of an ice, etc. substances are called catalysts.
• Catalysis is called homogeneous when
Redox Reactions
jm

reactant and catalyst are in same phase e.g.,

In such reactions, oxidation and for the manufacture of sulphuric acid.
reduction occurs, simultaneously.
NO(9, SO,9)
These are called disproportionation so,(4) +0,e)
reaction when the same element is
@

Oxidised as well as reduced. • Catalysis is called heterogeneous, when

reactant and catalyst are in different phase,
Oxidation
. It involves e.g., Haber's process for the synthesis of
addition of Oxvgen or any ammonia.
other electronegative element ike
luorine (F), chlorine (Cl), nitrogen Ngg) + 3H,(9)- Fe(s) 2NH (g)
(N), etc.
•
• Catalysis is called autocatalysis, when one of
It involves removal of hydrogen (H) the product increases the rate of the reaction
or any other electropositive element
i.e., acts as catalyst. e.g.,
like sodium (Na). It involves loss of
electroms i.e., increase in the CH,C00C,Hs + H,0
positive charge of ion. CH,COOH + C,H,OH

Reduction PERIODICTABLE
• It involves addition of hydrogen or • It is a tabular display of the chemical
any other electropositive element.
. It involves remnoval oxygen or any elements, organised on the basis of their
of properties.
other electronegative element. It • It
contains horizontal rows called periods
involves gain of electron, i.e., and vertical columns called groups.
decrease in oxidation state.
 GENERAL KNOWLEDGE~General Science 393
• It is the only block which contain metals,
Mendeleefs Periodic Law non-metals and metalloids.
Itstates that, 'the physical and chemical
properties of elements are the periodic Heavier elements show inert pair effect.
s and p-block elements are collectively
function of their atomic masses.
called representative elements.
Modern Periodic Law d-Block
It states that, "physical and chemical
properties of the elements are periodic
• It comprises 10 groups (3 to 12). These
functions of their atomic numbers" elements are called transition elements.
• General electronic coniguration of
Long Form d-block elements is (n-1)d-ns2

e
ofPeriodic Table • Elements of this block contain unpaired
electrons and are paramagnetic.
It is just graphical representation of Aufbau

nc
principle. It is based on the electronic These elemnents are generally coloured and
confguration of elements and contains used as catalyst.
118 elements. It is divided into four blocks Hg, Zn,Cu, Sc, etc., are d-block elements,
but not the transition elements.
$-Block
ra
• It contains 1
and2 group, i. e., hydrogen
f-Block
and alkali metals (Li, Na, K, Rb, Cs, Fr) . It usually offset below the rest of the periodic
and alkaline Earth metals (Be, Mg, Ca, tabie, cOmprises two rows of 14 elements.
Sr: Ba, Ra). General electronic called lanthanides and actinides
nt

configuration of these elements is respectively.

• General electronic configuration of this
• These elements are soft metals, block elements is (–2)f4 (n–I)
electropositive and form basic oxides. dl-10nsl-2
ie

-Block There are two series in this block 4f and 5f

. It series. 4f series elements are called
comprises the last six groups lanthanides and 5fseries elements are called
(13-18).
jm

actinides. Elements of this block are called

• General electronic configuration of
inner-transition elements and present in
this block elements is ns²np-6. IIIB (3) group only.
dnoug
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S-block p-block
IIA| IVA| VA
O
pas IA
IA VIA|VIA
1)(2) l(13)(14)|(15)(16)(17)l(18)
H He
1

Be B C N F
d-block or transition elements
4 10
Na Mg (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) Al
Si S C
3 IVB VB VIB VIIB
12|IB VIIB |B IIB 13 4 15 16 17 18
K Sc Ti V Mn Ni Cu Zn Ga
Ge As Se Br
K

Ca
4 19 20 22 25 262728 29 30 31
3233 34 35 B6
no
5
Sr Y Nb lc HL Rh Pd Cd Sn e Xe
37 38 40 41 42 43 45 46 47 48 49 50 5 52 53 54
Cs Ba La Hi Ta Re Os Ir Pt Au Hg TI Pb Po At Rn
6
66 56 57 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Fr Ra Ac RF Db Sa Bh Hs Mt| Ds Rg CnUut FI UUp Lv Uus|Uuo
87 88 89104|105|106| 107 10810911o111|112|113|114| 115116|117| 118|
Ce Pr Nd Pm Sm Eu Gd Tb
D
Ho Er Tm Yb
58 59 61 62 63 64 65 67 69 70 71
Th Pa Np PuAm Cm Bk FmMd No
90 91 92 93 94 9596 97 96 100 101 102 103
Fblock or inner-transition elements
394 GENERAL KNOWLEDGE~ General Science

• For p-block elements, they show variable

Newly Discovered Element valencies [P(3, 5), S(4, 6) but tendency to
a
Ununseptium, recently discovered, show higher valency decreases when ve
superheavy chemical element with atomic move down in a group due to inert pair
number 117, is a member of group-17 in the effect.
periodic table below the five halogens For d-block elements Fe(2, 3), Cu (1, 2) the
(fluorine, chlorine, bromine, iodine and
elements of same group may have different
astatine). Its synthesis was claimed in valencies, and the element itself exhibit
Dubna, Aussia by a joint Russian-American different valencies.
collaboration. In 2014, the GSI Helmholtz
Centre for Heavy lon Research in Germany Oxidation State
also claimed to have successfully repeated

e
• It is the hypothetical charge that an atom
original experiment. Ununseptium is a would have if all bonds of atoms of different
temporary systematic name that is elements were removed.

nc
intended to be used before a permanent • It is typically represented by integers, which
one is established. It is commonly called
can be positive, negative or zero.
element-117, instead of ununseptium.
It is +1 for hydrogen, – 2for oxygen (except
in peroxide i.e., -l and in F0 i.e., +2), +1
ra
Periodic Properties for sodium and potassium and +2 for
magnesium (Mg), calcium (Ca), strontium
and their Trends (Sr).
Periodic properties are those which -
It is 1 for fluorine (always).
shows a regular trend along a period is zero for a neutral molecule.
nt

It

and a group. Example

:
Calculation of oxidation number of
Mn in KMnO4
Atomic Size Y.
• It generally increases
on moving Let the oxidation number of Mn is
ie

KMnO, =1+ X+ 4(-2) 0=

down the group because number Or Therefore. the oxidation number of Mn in
shells increases.
KMnO, is +7.
• It decreases along a period from left
jm

to right. Thus, size of alkali metal is Metallic Character

largest and that of halogens is • It is the tendency of an
smallest in a period. element to form
cation by the loss of electrons.
• Smallest atom is hydrogen and • It decreases along a period from left to right
@

largest atom is cesium.

•
and increases in a group on moving
Most poisonous metal is plutonium. downwards.
Valency Ionisation Energy
• It is
the combining capacity
element.
of
an• It is the energy required to remove an
electron from the outermost shell of an
• It increases from I to 7 along a period isolated gaseous atom.
with respect to oxygen whereas with. It generally increases along a period
respect to hydrogen, it first increases from left to right but ionisation energy of Be,
from 1 to 4 and then decreases to 0. Mg, Ca, Sr is larger than the ionisation
• For alkali metal (i.e., sodium, energy of B, AI, In, TI, respectively.
potassium, etc.,) it is 1, for alkaline Moreover, ionisation energy of N, P is larger
Earth metals (i.e., magnesium, than ionisation energy of 0, S respectively.
calcium, etc.,) is 2, for aluminium, it • Itgenerally decreases in a group on moving
is 3 and for nitrogen it is 3. It remains downwards.
the same in a group.
• Fors-block elements, all the elements Electron Affinity (EA)
in a group have same valency. • It is defined as the energy liberated when an
extra electron is added to an atom.
 GENERAL KNOWLEDGE~General Science 395

• It increases across a period from left to Sodium and potassium burn in water
right but EA of II(2), 15 group and 0 while calcium loats over it.
group is 0 or positive. Copper (Cu) is the first metal used by
. It
decreases on moving down a goup. man.
• It is highest for chlorine. Pb (lead) is a bad conductor of electricity.
• Ti (Titanium) is called strategic metal.
Electronegativity
It is the tendency of an atom in a molecule Non-Metals and their Properties
to attract the shared electrons towards itself.
These may be solid, liquid or gas
It increases regulary along a period from left (bromine is the only liquid non-metal).
to right and decreases on moving down a
These are soft, non-lustrous, brittle,

e
group. It is highest for fluorine.
non-sonorous and non-conductor of heat
Metals and their Properties and electricity.

nc
•
These are the elements which are hard, These have low melting and boiling
lustrous, ductile, malleable, sonorous points.
and conductor of heat and electricity in
• These form oxides with oxygen which are
generally acidic.
. their solid as well molten state.
as
Examples are noble gases lie., heliumn
These form oxide with air. These oxides
ra
are generally basic, but oxides of zinc (He), neon-(Ne), argon (Ar), kypton
and aluminium are amphoteric, i.e., (Kr), xenon (Xe) and some other p-block
have acidic as well as basic properties. elements].
• Diamond is the hardest substance known.
These evolve hydrogen gas when reacts
nt

•
with water and acids. Iodine is lustroUS. Melting point is very
• Metals which are highly reactive high for diamond and graphite.
displace the less reactive metals from The order of hardness of SOme
substances is : diamond > corundum >
ie

their salts. The order of reactivity is :

potassium (K) > calcium (Ca) topaz > quartz.
sodium (Na) > magnesium (Mg) > Helium
aluminium (Al) > zinc (Zn) > iron (Fe)
jm

> lead (Pb) > hydrogen (H) > copper It is a noble gas (discovered by Lockyear
(Cu) > mercury (Hg) > silver (Ag) > and Janssen).
gold (Au) (Thus, gold is less reactive • It is used for filling balloons and other
metal). lighter aircrafts. Helium, when mixed
e.g., When iron nails are kept in copper with Oxygen, is used by deep-sea divers
@

sulphate solution (blue), iron being more for breathing and for respiratory patients.
reactive displaces the copper from copper It is used as a heat transfer agent in gas
sulphate solution and thus, the blue cooled nuclear reactors.
colour of solution disappears.
• Mercury (metal) is liquid at room Neon
temperature. It was discovered by Ramsay and Travers. It is
• Metal with lowest density is lithium. used in neon signs.
.
Tungsten is the metal having highest Argon
melting point.
. Reactivity It was discovered by Rayleigh and Ramsay. It
of metals increases while that is used to generate inert atmosphere for
of non-metals decreases on moving welding and to fll incandescent light bulbs.
down the group. A mixture of mercury vapours and argon gas
• Sodium and potassium are soft and is filled in tube
ights.
highly reactive metals. These react with
air and water. That's why these are kept Xenon
in kersene oil. Silver, gold and It is called stranger gas. Xe, when mixed
platinum do not react with air even on with Kr, used in high intensity, short
strong heating. exposure photographic flash tubes.
396 GENERAL KNOWLEDGE~ General Science

Uses of Some Important Metals Ores

Metals and Non-Metals Alurminium
(AI)
Bauxite (Al,0,-2H,0)
Corundum (Al,04)
• Ferrous Oxide (FeO) is used to Cryolite (Na AlF;)
prepare ferrous salts and green glass. Feldspar (KAISi Og)
•
Ferric Oxide (Fe,0) is used in Polassium Nitre (KNO)
(K)
jeweller's rouge. Carnalite (KCI- MgCl, :6H,0)
•
Silver Nitrate (AgNO,) is called Magnesium Magnesite (MgCO,)
(Mg) Dolomite (MgCO,- CaC0,)
lunar caustic and is used to prepare Epsom salt (MgSO, 7H,0)
the ink used during voting. Calcium Calcite (Ca CO,)
.
Silver lodide (Agl) is used for

e
(Ca) Flurospar (CaF;)
artificial rain.
• Copper (Cu) Cuprite (Cu,0)
Mercuric Chloride (HgCl,) is used to Copper glance (Cu,S)

nc
prepare calomel and as a poison. Copper pyrites (CuFeS,)
• Hydrogen
Peroxide (H,0,) is used as Silver (Ag) Ruby silver (Ag,S- Sb,Ss)
an oxidising agent, bleaching agent, Horn silver (AgCl)
as an insecticide and for washing old Zinc (Zn) Zinc blende (ZnS)
ra Calarmine (ZnC0,)
oil paintings.
Zincite (Zn)
Metalloids Mercury (Hg) Cinnatbar (HgS)
Tin (Sn) Cassiterite (SnO,)
These have properties of metals as well
as non-metals. They are present only in
nt

Lead (Pb) Galena (PS)

p-block. Their examples are arsenic, Cerrusite (PbCO,)
antimony, germanium, tellurium, Iron (Fe) Haematite (Fe,0,)
silicon and boron. Magnetite (Fe 04)
Siderite (FeCO)
ie

Minerals Uranium (U) Pitch blende (kernatite) (U,0,)

These are the substances in the form of Thorium (Th) Monazite
which metal is found in nature.
jm

• The main
constituent of pearl is METALLURGY
calcium carbonate (CaCO3).
•
Ruby and sapphire are chemically It is the process of extraction of metal from its
aluminium oxide, Al,03. Oes.
. Ores
@

In haemoglobin and myoglobin, iron

is present as Fe+,
Moderately reactive ores
Ores
Highly Moderately reactive Less
•
These are the minerals from which reactive reactive
melals
metal can be obtained conveniently melals melals
and beneficially.
• Allores are minerals but all minerals Electrolysis
Carbonale Sulphide
Sulphide
are not ores. ore ore ores
of fused
melals
Gangue or Matrix Calcination Roaling Roasting

These are the impurities associated Pure

Metal oxide
Melal
with the ore. melals
Relining
Ores of Some Important Metals Reduclion (smelling)
of melal
Metals Ores Impure melal
Sodium (Na) Chile salt petre (NaNO,)
Cormmon salt or brine Relining of impure melal
(NaCI)
Pure Metal
 GENERAL KNOWLEDGE~General Science 397

Calcination
• It is the process of heating the concentrated ore in absence or in limited supply of air
below its melting point. It is done for hydroxide or carbonate ore.
• It is done in reverberatory furnace.
Roasting
• It is the process of heating the concentrated ore in excess of air.
• It is used for sulphide ores.
• It is done in reverberatory furnace.
Smelting

e
It is the process of heating the oxides of elements with coke and flux above their melting
point.

nc
Flux and Slag
•
These are the substances which converts infusible impurities into fusible substances
called slag.
.
ra
These are of two types : Acidic flux such as SiO, (used to remove basic impurities) and
basic flux such as CaO, MgO (used to remove acidic impurities).
Electrolytic Refining
In electrolytic refining, anode is made up of impure metal and cathode is made by thin
nt

strip of pure metal.

Alloys
These are mixtures of two metals or a metal and a non-metal. They have properties
ie

different from the main metal. An alloy of mercury is called amalgam.

Alloys and their Uses

jm

Alloy Composition Uses

Brass Copper (70%) +Zinc (30%) In making utensils
Bronze Copper (90%) + Tin (10%) In making coins, bell, utensil
Copper (88%) + (10%) Tin+Zinc (2%) making gun, barrels, gears
@

Gun metal In
and bearings
German silver Copper (60%) +Zinc (20%) +Nickel (20%) Inmaking utensils
Solder Lead (50%) +Tin (50%) For soldering
Bell metal Copper (80%) +Tin (20%) For casting bells, statues
Munz metal Copper (60%) +Zinc (40%) In making coins

Magnalium Aluminium (95%) + Magnesium (5%) For frame of aeroplane

Duralumin Aluminium (94%) +Copper+Magnesium and For making automobile parts
manganese
Type metal Lead (80%) +Antimony (15%) +Tin (5%) Inprinting induslry
Stainless steel Iron (75%) +Chromium (15%), Nickel For making utensils and
(10%)+Carbon (0.5%) surgical cutlery
Babbit melal Tin (89%) +Antimony (9%) +Copper (2%) In making heater coil
Nickel+Chromium
398 GENERAL KNOWLEDGE~ General Science

bases reacts with non-metallic oxides to

ACIDS, BASES AND give salt and water which shows that
SALTS non-metallic oxides are acidic in nature.
• When dissolved in water, acids release
Arrhenius Concept H* ions and bases (or especially alkalies)
According to this concept, "acids are those releases OH ions.
substances which give H* ions in their HA + H,0 H,0t + A9
aqueous solution and bases are those
substances which give OH ions in their BOH+ H,0 +OHe
B*
aqueous solution." Acids like HCI, HNO, H,SO4, etc., and
HCl (ag) H+ C bases like NaOH, KOH, etc., are good
conductors of electricity in their aqueous

e
NaOH (ag) Nat+OH solutions.

nc
Bronsted LowIy Concept Some Important Points
According to this concept, "acids are Aqua Regia is a mixture of conc HCl and conc.
proton donors and bases are proton HNO, in a ratio of 3 :1 and is used to dissolve
acceptors." noble metals like gold, platinum, etc.
CHCO0H +H,0 +
CH,CO0
ra
H,0* Pickles are always kept in glass jar because
Acid Base Conjugate Conjugate acid present in them reacts with metal of
Base acid metallic pot.
H,0 + H,0 OH +
H,0+ • Acidity is the number of replaceable OH
nt

NH, + NH NH, + NH,* ions, e.g,, it is 1 for NaOH, 2 for

.
Ca(OH) Whereas Basicity represents
Lewis Concept the number of replaceable H* ions, e.g.,
According to this concept, "Acids are it is 1 for HCI, 2 for H,SO4
ie

electron pair acceptors and bases are

electron pair donors."
Sources of Some Naturally
:NH, +BF, HN: BE Occurring Acids
jm

Base Acid
Acids Sources
Properties of Citric acid Lemon, orange, grapes
Acids and Bases Maleic acid Unripe apple
@

Tartaric acid Tamarind

• Acids have sour taste and turns blue
litmus red. While, bases have bitter taste Acetic acid Vinegar
and turns red litmus blue. Lactic acid Milk
• Acids reacts with metal to liberate
Hydrochloric acid Stomach
hydrogen gas. Oxalic acid Tomato
Acid + Metal Salt + Hydrogen gas.
• Bases also reacts with some metals to
Uses of Some Acids and Bases
liberate hydrogen gas.
e.g., Zn + 2NaOH Acids Uses
NaZnO, + H, Nitric acid, oxalic
• Acid photography
and base reacts together to form salt acid
and water and the reaction is called
Sulphuric acid petroleum exploration
neutralisation reaction.
Acid + Base Salt + Ha0. Hydrochloric acid leather industry
+
HCI(ag) NaOH(ag) Benzoic acid, preservation for fopd
NaCKag)+ H,0() formic acid, stuff
• Acids reacts with metallic oxides to give citric acid,
salt and water which shows that metallic acetic acid
oxides are basic in nature. Whereas,
GENERAL KNOWLEDGE~ General Science 399

Bases Uses Salts

Calcium hydroxide manufacturing of bleaching These ae the product of neutralisation
calcium oxide powder reaction between an acid and a base
Magnesium antacid, in sugar industries e.g.,
hydroxide
HNO, (a) + KOH (ag)
Sodium hydroxide manufacture of hard soaps acid base
and drugs, paper and textile KNO, (a) + H,O ()
industry, petroleum refining salt water
Potassium manufacture of soft soaps These are of the following types :
hydroxide
Mixed Salt

e
pH Value These are obtained by neutralisation of
• It is a measure of acidity or basicity of a an acid by two base or a base by two

nc
solution. acids. e.g., bleaching powder (CaOCl).
• It is defined as the negative logarithm of the
concentration in mol/L of hydrogen ions Double Salt
which it contains, .e., It is obtained by mixing tvo or more
pH =-log [H"1= log 1
ra salt, e.g.
H
Alum (K,S0,-Al,(SO, ),24H,0),
[H]= 1x 10-pH Mohr Salt (FeSO, (NH, ),S0, 6H,0).
• It is 7 for neutral solution, greater than 7 for Important Salts
nt

basic solution and less than 7 for acidic

solution. Common Salt
• pH sone connon substances ae:
of
•
. It is sodium chloride (NaCI).
is
It obtained from sea water.
ie

Substance phH Substance pH • It is also known as table salt.

Gastric juice 1.0-3.0 Rain water 6.0
Soft drinks 2.0-4.0 Tears 7.4 Baking Soda
jm

Lermon 2.2-2.4 Sea water 8.5 •

Milk of
It is sodium hydrogen carbonate
Vinegar 2.4-3.4 (NaHC0). It is a mild non-corrosive
10.5
magnesia
base.
Urine 4.8-8.4 Milk (cow) 6.3-6.6 .
(human) When mixed with a mild edible acid
@

Saliva 6.5-7.5 Blood 7.30-7.42

such as tartaric acid it is called
(human) plasma baking powder and is used to make
(human) bread or cake soft and spongy.
• It is used as mild antiseptic for skin
Indicators
.
infections, in soda-acids and as fire
These are the substances which give extinguishers.
acidic and Ant or bee sting contains methanoic or
different colours in basic•
solutions. formic acid. Due to which victim feel
• Some
indicators and their colour in acidic pain and irritation. Use of a mild base
like baking soda is a remedy for it.
and basic medium are:
Indicators Colour Washing Soda
|In Acid It is chemically sodium carbonate
In Base
decahydrate (Na,C0-10H,0) and is
Phenolphthalein Colourless Pink
used in glass, soap and paper industries
Methyl orange Orange Yellow and also for removing permanent
Methyl red Red Yellow hardness of water.
Phenol red Yellow Red
400 GENERAL KNOWLEDGE ~ General Science

Bleaching Powder ELECTROCHEMISTRY

• It is chemically Ca(0CI)CI
CaOCl2 It is the study of production of electricity from
energy released during spontaneous chemical
• It is used for bleaching cotton and
reactions and use of electrical energy to carry
linen in the textile industry, for Out non-spontaneous chemical
bleaching wood pulp in paper transformations.
factories.
• It is used for disinfecting drinking ELECTROLYSIS
water.
The process in which a non-spontaneous
Plaster of Paris reaction is carried out by using electrical

e
• It is chemically calcium sulphate energy.
It is used

nc
hemibydrate CasO,H,o and
in production of oxygen for space craft and
•
nuclear submarines.
obtained by heating gypsum
(CaSO, -2H,0). It contains half in layering metals to fortify them.
molecule of water of crystallisation. in production of hydrogen for fuel.
ra
• It is a white powder and on mixing• in electrolytic etching of metal surfaces like
with water, changes into a hard solid tools or knives with a permanent mark or
mass, called gypsum. logo.
• It is Used to plaster fractured bones. Electrometallurgy is the process of
nt

for making toys, materials for reduction of metallic compound into pure
decoration and for making smooth • metal by electrolysis.
surfaces. Anodisation is an electrolytic process that
makes the surface of metals resistant to
Copper Sulphate (Blue Vitriol)
ie

COrTosion.
Copper sulphate when anhydrous, is • Electrolysis of brine (the water, saturated or
white and when associated with water nearly saturated with salt, usually sodium
jm

of crystallisation (i.e., CuSO, -5H,0), is chloride) gives hydrogen and chlorine. The
blue, so it is called blue vitriol. It is used products are gases.
to test the presence of water. 2NaCl + 2H,0 2NaOH + H, + Cl,
Lime
. It is Faraday's Lawsof Electrolysis
@

chemically calcium oxide (Ca0)

and also called quicklime.
First Law of
Electrolysis
• It is used in the manufacture of glass, It states that the quantity of elements
cement, etc., and for drying ammonia Separated by passing an electric current
and alcohol. through a molten or dissolved salt is
• Excessive use of fertilizers makes the Proportional to the quantity of electric charge
soil more acidic. To neutralise it PaSSed through the
circuit.
W o Q; w= ZQ =Zit
quicklime is added to soil as acidic
soil is not good for growth of the (Charge (Q=Current (i) xTime (t)
plant. Second Law of Electrolysis
Potassium Nitrate The amount of different substances liberated
It is used as fertiliser, in gun powder at the electrodes by the same quantity of
(C+S+ KNO3), in matchsticks, etc. electricity passing through the electrolytic
solution are proportional to their chemical
Magnesium hydroxide equivalent weights.
It is used as a remedy for hyper acidity Wo E or
in stomach. W,
GENERAL KNOWLEDGE~ General Science 401)

• It is used in automobiles and invertors.

Electrochemical Cell a
• It is a device that produces an electric tConsists of lead as anode and grid of
lead packed with lead dioxide (PbO,) as
CUIrent firom energy released by a
spontaneous redox reaction (in short which cathode. A 38% solution of sulphuric
converts chemical energy into electrical acid is used as an electrolyte.
energy). This kind of cell includes the • It consists of a series of six identical
galvanic cell or voltaic cell. cells assembled in series. Each cell
• It has two conductive electrodes, i.e., may produce a potential of 2 V, hence
anode (at which oxidation occurs) and overallvoltage produced is 12 V.
cathode (at which reduction occurs). PbSO, is formed when lead storage
• It contains an electrolyte in between the battery is in use and lead dioxide are

e
electrodes, which contains ions that can formed when it is charged.
move fireely.

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Fuel Cell
BATTERY These are galvanic cells which use energy
of combustion of fuels like hydrogen (H,),
• It is an arrangement of one or more cells
methane (CH,), methanol (CH,OH), etc.,
connected in series. as the source to produce electrical energy.
ra
• It is basically a galvanic cell. e.g., hydrogen-oxygen fuel cell.
These are of two types
1. Primary batteries (non-rechargeable)
Corrosion
• It is the process of oxidative
e.g., dry cell, mercury cell etc.
nt

deterioration of a metal surface by the

2. Secondary batteries (rechargeable) e.g.,
action of environment to form
lead storage battery, nickel- cadmium
battery. unwanted products.
• e.g., conversion of iron into rust
ie

Lechlanche Cell or Dry Cell [Fe,O,-x H,0], tarnishing of silver

(due to the formation of Ag,S),
• It consists of a zinc container that acts as
development of green coating of
anode and carbon (graphite) rod Cu(0H),-CuCO3
jm

(basic copper
surrounded by powdered manganese carbonate)] on copper and bronze. It is
dioxide and carbon which acts as cathode. basically an electrochemical process.
It contains a paste of NH, Cl and ZnCl, in •
between the electrodes. Corrosion of iron is called rusting. It is
accelerated by the presence of
@

• It is used in transistors and clocks.

impurities i.e. H+, electrolytes such as
• It
has a potential of 1.5 V. NaCl, gases such as CO2, SO2, N0,
NO2, etc.
Mercury Cell •
Formation of a layer of aluminium
• It is suitable for the low current devices oxide over aluminium surface protects
like hearing aids and camera, etc. the metal from further corrosion.
• It consists of zinc-mercury amalgam as
•A sliced apple turns brown if kept
anode and a paste of Hg0 and carbon as open for somne time due to the
cathode. The electrolyte is a paste of KOH oxidation of iron present in the apple.
and ZnO.
prevented by the following methods
• It
has potential of 1.35 V. This potential It• is
By electroplating.
remains constant during its whole life. • By surface coating
(.e., coating of
Lead Storage Battery surface with oil, grease, paint and
• It is a secondary battery. varnish), by alloying, by galvanisation
• It acts as electrochemical cell during of iron (process of deposition of a thin
layer of zinc over iron surface).
discharging (i.e.,during use) and as
electrolytic cell during charging.
402) GENERAL KNOWLEDGE ~ General Science

•
CARBON AND ITS Urea It is the first synthesised organic
compound (discovered by Wholer).
COMPOUND •
Acetic Acid It was the first organic
compound synthesised in the laboratory
Carbon from its elements.
It is a member of group 14 in the Periodic
Table, with symbol C and atomic number 6. Hydrocarbons
Ithas three crystalline allotropes • These are the compounds of only carbon
and hydrogen.
Graphite These are of three types
• It is opaque and black.

e
• It is a very good conductor of electricity. Saturated Hydrocarbons
• It is soft enough to form a streak on • These compounds contain only single

nc
bonds.
. paper:
It is Ised for thermal insulation (i.e. • These are also called allkanes Or
firebreaks and heat shields). paraffins and have general .... formula
• It is a very good lubricant. CH2 *2 where, n =12,3 Methane
is the first member of this group.
ra
Diamond
• It is highly transparent. Unsaturated Hydrocarbons
• These have atleast one double (=) or
• It is the hardest material known.
• It is an electrical insulator. triple (=) bond and are called alkene
nt

. and allkynes, respectively.

Under normal conditions, it has the . These have general formula C,Hg, for
highest thermal conductivity of all alkene and CHa- 2 for alkynes.
known materials. • Ethylene
(C,H,) It is the first member of
ie

• It is an ultimate abrasive.
alkene and acetylene (C,H) is the first
Fullerenes member of alkyne.
• Can looks like a soccer
ball (or bucky Aromatic Hydrocarbons
jm

ball).
• These have ring structure with
• It alternate
contains 20 six membered rings and
12 five membered rings carbon atoms.
of double bonds
(Huckel's rule).
and obey (4n+2) e
• It acts as a wonderful lubricant and the
@

• Benzene is the first member of aromatic

alkali metal compounds of Csn are used
as superconducting substance at the hydrocarbons.
temperature range of 10-40 K.
Functional Group
Graphene • It is an atom or group of atoms in a
Graphene is an allotrope of carbon. Its molecule, which is responsible for the
structure is one-atom-thick planar sheets of chemical properties of the molecules.
carbon atoms that are densely packed in a •-OH is alcoholic group, –CHO is
honeycomb crystal lattice. The term graphene aldehyde group, >C=0 is keto group,
was coined as a combination of graphite and -COOH is carboxylic acid group, -O
the suffix-ene by Hanns-Peter Boehm, who is ether group.
discovered single-layer carbon foils in 1962.
Homologous Series
Organic Compounds • It is a series of compounds in which
adjacent members differ by a CH
•
These are the compounds of mainly unit (14 unit mass).
carbon and hydrogen or compounds of a
carbon and hydrogen with other Al members of homologous series
elements like phosphorus, oxygen, have same functional group and same
nitrogen, sulphur, halogens etc. chemical properties.
GENERAL KNOWLEDGE~General Science 403)

Isomerism Glycerine (CzH,0)

Compounds having the same molecular It is LIsed to synthesise explosive
formula, but different structure are called nitroglycerine, stamp ink and boot polish.
isomers and the phenomenon is called
isomerism. e.g., C,H;0 can have the Formic Acid (HCOOH)
following structures CH0CH and It is used as a preservative for fruits and
CzH,OH. juices, in leather industry and in
coagulation of rubber.
Uses of Some Important Acetic Acid (CH,C0OH)
Organic Compounds It is used in vinegar, medicines and act as a
solvent.

e
Methane (CH)
It is used to manufacture printer ink, Oxalic Acid (CH 04)

nc
methyl alcohol and to obtain light and It is used in printing of clothes, in
energy. photography and in the synthesis of coaltar.
Ethylene (C,H,) Glucose (CgH,pOs)
It is used to prepare mustard gas (war gas) It is used for the synthesis of alcohol and as
and for ripening of fruits. a preservative for fruit juice.
ra
Glycol (C,HO,) Benzene (CGHe)
It is used as an antifreeze mixture in car It is used as a solvent for oil fat and in dry
radiator and prevent the freezing of fuel in cleaning. Sodium benzoate is a food
space crafts. preservative.
nt

Acetylene (C,H,) Toluene (CçH,CH)

It is used to generate light, to weld metals It is used to synthesise explosive TNT, for
as oxy-acetylene flame and to prepare dry cleaning and for the synthesis of
ie

synthetic rubber (neoprene). medicines like chloramine.

Methyl Alcohol (CH,OH) Phenol (CeH,OH)
It is used as a fuel with petrol, used to It is used to synthesise explosive,
jm

synthesise varnish and polish, used to 2, 4, 6-trinitro-phenol (picric acid) and

denature ethanol. bakelite.
Chloroform (CHCl) Ethyl Alcohol (C,H,OH)
It is used as an anaesthetic and to preserve It is used for drinking as a liquOr, in
substances obtained from plants and medicine to prepare tincture and as an
@

animals. It converts into poisonous insecticide and as a fuel with petrol.

phosgene (COCI,), when exposed to
sunlight. So, it is kept in dark bottles.

Name Rum Brandy Whisky Beer Champagne Cider

Alcohol % 45-55% 40-50% 40-50% 3-6% 10-15% 2-6%
Raw material Molasses Grapes Barley Barley Grapes Apple
404) GENERAL KNOWLEDGE~ General Science

• Bituminous is the most common variety

ENERGY RESOURCES of coal. Coal is used for the synthesis of
water gas and producer gas.
Natural Resources
These resources are obtained by nature lilke Petroleum
air, water, mineral, sunlight, etc. • It is a dark coloured oily liquid
These are of two types
with offensive odour. It is also called rock
oil, mineral oil, crude oil or black gold.
Renewable Natural Resources .
When subjected to fractional distillation,
These are available in excess amount e.g., it gives different products at different
air, sunlight, etc.
temperatures.

e
Non-Renewable Natural Liquefied Petroleum
Resources

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These resources are available in limited
Gas (LPG)
It is a mixture of rbutane, so-butane and some
quantity, e.g., minerals, coal, petroleum,
propane.
natural gas, etc. • It is easily compressed under pressure as
Fuels
ra liquid and stored in iron cylinders.
These are the substance which produce A strong foul smelling substance called

heat and light on combustion. ethyl mercaptan, is added to LPG which

detect the gas leakage.
Coal
nt

• It is believed to formed by the slow Compressed Natural

carbonisation of vegetable matter buried Gas (CNG)
underneath the Earth from centuries It consists mainly of methane (959A)
ago, in limited supply of air under hioh
ie

which is a relatively unreactive

temperature and pressure prevailing
hydrocarbon and makes its nearly
there.
• complete combustion.
It is available in different varieties : Peat
lt has octane rating of 130.
jm

(60% C), lignite or brown coal (70% C)

bituminous coal (80% C) and anthracite
(90% C).

Different Fuels, their Composition and Source

@

Fuel Composition Source

Waler gas Carbon monoxide (Co) + hydrogen (H) By passing steam over red
hot coke
Producer gas Carbon monoxide (Co) + nitrogen (N) By passing insufficient air
Over red hot coke

Oil gas Methane (CH4)+ ethylene (CHa) By destructive distillation of

+ acetylene(CH) kerosene
Coal gas Hydrogen (H,) + methane (CH,) By fractional distillation of
+
ethylene + acetylene + CO wOod
Nalural gas Methane (83%) + ethane From petroleum
LPG Butane (C,Hho)+ propane (CHa) From oil wells
Biogas or Gobar Methane (CH4) + carbon dioxide (CO,) +
From organic wastes
gas hydrogen (Hg)+ nitrogen ( N)
 GENERAL KNOWLEDGE~General Science 405)

Different Fractions Obtained by Fractional Distillation of Petroleum

S.No. Fraction Boiling Range Uses
Uncondensed gases room ternperature Fuel gases, refrigerants, production of
carbon black, hydrogen
2
Crude naphtha (lIt gives 30-150°
on refractionation)
) petroleum ether 30-70° Solvent
(ii) petrol or gasoline 70-120° Motor fuel, dry cleaning, petrol gas
(i) benzene derivatives 120-150° Solvent, dry cleaning
3
Kerosene 150-250° Fuel, illuninant, oil gas

e
4
Gas oil
250-350° As a fuel for diesel engines converted to
5 Fuel oil
gasoline by cracking

nc
6 Diesel oil
7. Lubricating oil 350-450° Lubrication
8 Paraffin wax > 500°C Candles, boot polish, wax paper
9. Vaseline > 500° C Ointments, lubrication paints, road
surfacing as fuel
ra
Some Important Physical Octane Number
Quantities • Octane
number is the percentage of
iso-octane in the mixture of iso-octane
nt

Calorific Value and 7-heptane which has saime

• It is defined as knocking properties as the fuel sanple.
the heat obtained when 1 g
of a fuel is burnt in excess of oxygen and is • It is a measure of quality of petrol
expressed in kcal/g. (gasoline). It is zero for heptane and
ie

Calorific value of some important fuels are as 100 for iso-octane. (2, 2, 4-trimethyl
follow pentane).
Calorific Value (kJ/g) • Higher the octane number, better is
Fuel
jm

Coal 25-32
the fuel.
Kerosene oil
48 Cetane Number
Petrol 50 • Cetane number is the percentage of
Diesel 45
@

cetane in the mixture of cetane and

Bio gas 35-40 O-methyl naphtalene which has same
LPG 50 knocking properties as the fuel sample.
Wood 17 • It is a measure of quality of diesel. It is
Cow dung 6-8 100 for Cetane and 0 for o-methyl
Ethanol 30 naphthalene.
Methane 55
Hydrogen 150 Flame
Natural gas 35-50 It is the hot part of fire and has three
• parts
Hydrogen is the fuel of future.
• Alcohol, when mixed with petrol, is called
1. Innermost Region of Flame It is
power alcohol. It is an alternative source of black because of the presence of
unburned carbon particles.
energy.
2. Middle Region It is yellow luminous
• For the combustion of a substance, its due to partial combustion of fuel.
ignition temperature should be low.
3. Outermost Region It is blue
Note Substances that are used to reduce the (non-luminous) due to complete
knocking property are known as combustion of fuel.
anti-knocking compounds. e.g., Tetra Ethyl
Lead (TEL)
 406 GENERAL KNOWLEDGE~ General Science

It is the httest part of flarneand is used by the Gass

Goldsmith to heat the gold. • It is an amorphous or transparent
solid, also called supercooled liquid.
Fire Extinguisher • It contains mainly silica (SiO,).
In case of electric fires and oil fires, water
It can be of the following types
cannot be used as an extinguisher as it is a
conductor of electricity and oil being lighter comes 1. Soda or Soft Glass is sodium
above the water. Such fires are extinguished by calcium silicate (Na,0-CaO- 6Si0,)
carbon dioxide. It is the ordinary glass and used for
making bottles, window panes, etc.
2. Potash Glass Or Hard Glass
Safety Match Stick

e
contains potassium (from KC04).
Safety match stick contains a mixture of It has higher softening temperature.

nc
antimony trisulphide and potassium chlorate It is used for making chemical
at its one end. ts box side contains a mixture apparatus such as beakers, flasks,
of powdered glass and red phosphorus. funnel, etc.
3. Crown Glass contains potassium
Man-Made Materials oxide (K,0), barium oxide (BaO),
ra
Soaps boric oxide (B-0) and silica (SiO,).
It is used for optical apparatus.
These are sodium and potassium salts of
4. Flint Glass contains lead oxide
higher fatty acids. e.g., sodium palmitate,
sodium stearate, etc. (PbO) and used in optical
nt

instruments like lenses, prisms.

Detergents 5. Crook's Glass contains cesium
oxides. It is used for spectacles as it
•
These are sodium or potassium salts of long absorbs UV rays.
chain alkyl or aryl sulphonates or sulphates
ie

e.g., sodium allkyl sulphonate, sodium allkyl 6. Jena Glass contains B,0, and
benzene sulphonate, etc. alumina. It is stronger and more
•
These are also called soapless soap. resistant to acids and alkalies, that's
jm

• why used for making laboratory

Detergents form lather with hard water.
bottles, for keeping acids and
• Detergents cause pollution but straight alkalies.
chain alkyl group containing detergents are 7. Milky Glass is prepared by adding
biodegradable and do not cause pollution. tin oxide (SnO), calcium phosphate
@

• The cationic detergents are used as fabric [(Caz(PO,)]or cryolite (NagAlF;) to

softeners and germicides while non-ionic the melt glass.
detergents are used as liquid dish washing 8. Glass Laminates is made by fixing
detergents. polymer sheets between layers of
glass. It is used to make windows
Fertilisers and screens of cars, trains and
•
These substances increase the fertility of aircraft. Specially manufactured
soil by providing elements essential for the glass laninates are Used as
growth of plants like nitrogen, phosphorus bulletproof material.
and potassium. e.g., basic calcium nitrate
[CaO-Ca(NO3)21, ammonium sulphate Different Substances gives
[(NH),S041. These two chemicals Different Colours to Glass
increases the acidity of soil which can be Colour Substance Added
removed by adding lime.
Red Copper () oxide (Cu,0)
• Other examples are calcium cyanamide or Chromiurm oxide (Ci,0,)
Green
nitrolim (CaCN), Urea or carbamide (it
does not effect the pH of soil), calcium Violet Manganese oxide(MnO,)
super phosphate or super phosphate of lime Blue Cobalt oxide (CoO)
[Ca(H,PO,)+2CaSO, -2H,01. Brown Iron oxide (Fe,0)
GENERAL KNOWLEDGE ~ General Science 407

Cement or Portland • Dettol is a mixture of chloroxylenol and

O-terpineol. Chloroxylenol is responsible
Cement for its antiseptic property.
• It is a complex material containing
the. Antibiotics are obtained from
silicates and aluminates of calcium microorganisms and used to destroy the
with small amount of gypsum. other microorgarnisms e.g., penicillin,
• It has
the followingconposition (discovered by A. leming in 1929)
Calcium oxide (CaO) = 50-60% ampicillin, amoxycillin (all are narrow
Silica (SiO,) = 2025% spectrum), ofloxacin, tetracycline,
Alumina (Al,Oz) = 5-10% chloramphenicol (all are broad
spectrum).
Magnesium oxide (MgO) = 2-3%

e
• lt is manufactured from limestone and Antimalarial are used to treat malaria.
clay. If cement contains excess lime,
e.g.. chloroquine.

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Cracks during settings can occur and if • Sulpha drugs are alternatives of
lime is less, cement is of weak strength. antibiotics, e.g., sulphanilamide,
• Gypsum decreases
the rate of setting of sulphadiazine, etc.
cement. •
Antacids are used as a remedy for acidity.
ra e.g., magnesium hydroxide, sodium
•A paste of sand, cement and water is
called mortar and is used for joining bicarbonate (baking soda), etc.
bricks and plastering walls. •
Pesticides are used to destroy the
• A mixture of stone chips (gravel), sand, organisms that harm the crop.
cement and water is knoWn as concrete These are of the following types
nt

and is used for flooring and making 1. Insecticides e.g., DDT, aluminium
roads. phosphate, gammexane.
• Concrete with steel bars and wires is
2. Fungicide e. g., bordeaux mixture.
called Reinforced Concrete (RC) and
ie

3. Herbicides e.g., benzipram,

used for constructing roofs, bridges and benzadox.
pillars.
4. Rodenticides e. g., aluminium
jm

Medicines phosphide.
These are the chemicals used for the
treatment of diseases and reduce Polymers
suffering from pain. These are classified They are made up of many repeating units
known as monomers. Some important
@

•
Analgesics are used to reduce pain. olymers such as plastics, fibres and rubber
are discussed belovw.
e.g., aspirin, paracetamol, morphine,
etc. Plastics
• Antipyreties
is used to reduce body . These are cross-linked polymers (a
temperature during high fever, e.g. substance having high molecular weight
paracetamol, aspirin, phenacetin, and repeating unit) and are very tough.
analgin and novalgin. • Lac is a
• Tranquilisers are used to treat stress, natural plastic (polymer).
mild and severe mental disease. These These are of two types
1. Thermoplastics are the polymers which
are also called psychotherapeutic
can be easily softens on heating and hard
drugs. e.g., equanil, valium, veronal,
on cooling e.g., polythene, polystyrene,
serotonin, chlorodiazepoxide,
meprobamate, etc. polyvinyl chloride, teflon etc.
• Antiseptics 2. Thermosetting plastics are the
prevent the growth of
microorganisms or kill them but are not polymers which undergo permament
harmful to living tissues. e.g., dettol, change on heating due to excessive
savlon, iodine tincture, boric acid, Cross-linking. These cannot be reused,
e.g., bakelite.
hydrogen peroxide, etc.
 408) GENERAL KNOWLEDGE ~ General Science

Some Important Polymers and AIR, WATER

their Monomers
Polymer Monomer Air or Atmosphere
• Air a homogeneous mixture of
is
Polyethylene Ethylene
Polystyrene
different gases.
Styrene
• It has the following composition : 78%
Polyvinyl chloride Vinyl chloride
(PVC) nitrogen; 21% oxygen, 0.03-0.05%
Polytetrafluoro Tetratluoro ethene
carbon dioxide (C0,), argon, etc.
ethylene (PTFE) or • An atmosphere is a layer of these gases
teilon surrounding a planet or other material
body of sufficient mass that is held in

e
Bakelite Formaldehyde +
Phenol place by the gravity of the body.
Urea formaldehyde Urea + Formaldehyde

nc
resin Constituent of
Atmosphere
Melmac Melarmine + It has different density at different heights
Formaldehyde
from sea level. Thus, several layers are
formed. These layers are
Fibres
ra
These have strong intermolecular forces Troposphere
like hydrogen bonding. e.g., nylon-66, • It is the lowest layer of atmosphere,
dacron, orlon, etc. extend upto a height of 18 km from sea
level.
nt

Natural Rubber • It is aturbulent and dusty zone which

It is an elastomer. It is a polymer of isoprene contains air (N2, O2, CO,) much water
(2-methyl-1, 3 butadiene). It is also called vapours and clouds.
Cis-polyisoprene. Synthetic rubber
ie

(neoprene) is a polymer of chloroprene. Stratosphere

• It is insoluble
in water, dilute acids and It lies between 18-60 km above sea level.
alkalies, absorbs a large amount of water • It is the laver which contains ozone
jm

and has low tensile strength and layer (protects us from harmful UV rays
elasticity.
• It is
coming from the Sun), so called
heated with sulphur compounds at 0zonosphere.
373K in the presence of ZnO to improve
the properties. This process is called Mesosphere
@

vulcanisation of rubber. • It extends from 60-85 kn above sea

•
Ifit is Vulcanised with 5% S, it is used for level.
making tyres and if with 30% sulphur, it is • Its temperature decreases with height
used in making battery cases. and reaches to -100° C. That's why
• Trans-polyisoprene
is called when any meteors enter in mesosphere,
gutta-purcha. it burns up.
• Thiokol rubber is a polymer of ethylene
chloride and sodium polysulphide and is Thermosphere
used in the manufacture of hoses, tank It extends up to 10-50 km above sea
lining, engine gaskets and rocket fuel. level.
• In this region, the temperature can rise
Explosives to l500°C, a person would not feel warm
Some examples of explosives are because of the extreme low pressure.
trinitrotoluene (TNT), nitroglycerine or
The international space station orbit is
trinitroglycerine (TNG), cyclotrimethylene also in thermosphere.
trinitroamine (RDX, also called cyclonite).
GENERAL KNOWLEDGE ~ General Science 409)

Exosphere Carbon Dioxide (CO,)

• It lies between 500-1600 km above sea • It is used by plants for photosynthesis.
level. • It is 1.5 times heavier than water.
• This egion contains ionised gases. It turns the lime water milky which
• Beyond this region, interstellar space is disappears in the excess of CO, due to
present. conversion of millky calcium carbonate
(CaCO) into soluble calcium
Major Gases in Air bicarbonate.
It is used to extinguish fire and for
Oxygen (O,) artificial respiration when mixed with
• It was discovered by K Scheele.

e
Oxygen (carbogen).
• It is obtained during photosynthesis.
It is dangerous to have charcoal fire
• It is colourless, odourless,
neutral gas burning in a closed room because it

nc
which gets adsorbed over alkaline produces carbon monoxide gas, which
Pyrogallol. is suffocating.
• It is non-combustible, but helps in Plants respire at night and releases
combustion. It form oxides with metals CO, which reduces oxygen content of
ra
and non-metals. air required for breathing, so it is
• It is used for artificial respiration and in dangerous to sleep under trees at night.
oxy-hydrogen flame and, oxygen-ethylene Eno (fruit salt) produces effervescence
flame and oxygen-acetylene flame (used if dissolved in water due to evolution of
for welding) and as a rocket fuel. CO, gas.
nt

•
Metal oxides are generally basic but Water (H,0)
alumina (Al ,03), zinc oxide (ZnO) and tin
Oxide (Sn0) are amphoteric oxides. • It contains two elements : hydrogen and
ie

• Oxygen (H,0). It constitute about 70%

Carbon dioxide (C0,) is acidic while
part of Earth.
carbon monoxide (CO) is neutral.
It is a universal solvent and maintains
Ozone (O;) the body temperature due to its high
jm

• It is an allotrope of oxygen.
specific heat.
• It is used as an insecticide, in purification It has boiling point 100° C and freezing
of water, to preserve food, to synthesise point 0°C. Its density is maximum at
4°C.
artificial silk and camphor, act as a
@

bleaching agent. Types ofWater

Nitrogen (N) There are different types of water
• It was discovered by Rutherford (in 1771). Soft water Soft water easily forn lather
with soap due to absence
odourless, calcium and magnesium. of
• It colourless, soluble salts,
is a
non-combustible, non-poisonous gas.
• It is Hard water It does not form lather with
neutral and ighter than air soap due to presence of Calcium and
N2.
. containing magnesium salts.
It is filled in sealed packets and bulbs to It is of two types
create inert atmosphere.
• Living beings die in an
environment of Temporary Hard Water
nitrogen. It contains bicarbonates of calcium and
• Soil contains several pores filled with air magnesium.
containing N,. At the time of raining these It is converted into soft water by boiling
pores get flled with water. That's why or by adding calculated quantity of
earthworm come at the surface to breath. calcium hydroxide (Clark's process).
410) GENERAL KNOWLEDGE~ General Science

Permanent Hard Water Soil Pollution

• It contains sulphates and chlorides of It is alteration in soil. It is caused by
calcium and magnesium. pesticides, insecticides (e.g., DDT, BHC etc)
• It is converted into soft water by herbicides (e.g., sodium chlorate), fungicides
adding sodium carbonate (Na,C04), or (e.g., organomercury compounds).
calgon or zeolite.
Hazardous Effect of Pollution
Heavy Water
It isdeuterium oxide, D-0 (molecular mass
Greenhouse Effect
20). It is used as a moderator in nuclear It is the heating of Earth and its objects
reactors, in the study of mechanisms of because of the trapping of IR radiations by

e
chemical reactions involving hydrogen and carbon dioxide (CO,), methane (CH, ), nitric
its compounds, etc. oxide (NO), 0zone (0), chlorofluoro carbons

nc
(CFCs) and water vapours.
Global Warming
POLLUTION • It is a result of increased concentration of
Pollution isthe contamination of greenhouse gases.
material particles or energy into the
ra
It may result in melting of ice caps and
natural environment. It causes adverse glaciers, spreading of several infectious
effects on the ecosystem.
diseases like malaria, sleeping sickness,
Types of Pollution etc.
nt

Acid Rain (By Robert Augus)

Air Pollution • It has pH less than 5. It is due to the
• It occurs when any harmful gases, presence of oxides of nitrogen and sulphur
dust, smoke enters into the
ie

atmosphere and make it difficult for in air that dissolve in rain water and forms
plants, animals and humans to nitric acid and sulphuric acid.
• It damages the buildings and other
survive.
structures made up of limestone and
jm

• Common respiratory diseases such as

results in several diseases such as skin
asthma, bronchitis can occur. infections.
• pH of normal rain water is 5.6.
Water Pollution
• It is due to the presence of foreign
@

substances like sewage, algae, soluble

Pollutants
salts, etc., in water. These are the substances that contaninate the
two types
• It can also be due to presence of environnent and of
metals in water. This pollution causes Primary Pollutants
following diseases.
These persist in the environment in the forIM
Metal Disease in which they are produced e.g., sulphur
Chromium and Cancer dioxide (SO), nitrogen dioxide (NO,), etc.
Arsenic
Cadmium Itai-itai
disease
Secondary Pollutants
Mercury Minamata disease
• These are the products of reaction of
primary pollutants e.g., PAN
• For a healthy aquatic life, dissolved (Perocyacylnitrates), ozone (O), aldehyde,
oxygen (DO) is 5-6 ppm. etc.
• For clean water, BOD (biochemical •
The order of different pollutants to cause
Oxygen demand) is less than 5 ppm pollution is carbon monoxide (CO), S0, >
while for highly polluted water, it is 17 hydrocarbon > particulates > nitrogen
Ppn or more. oxides.
GENERAL KNOWLEDGE ~ General Science 411)

• It is formed in cool humid climate when

Carbon Monoxide (CO) carbon soot particles combine with
• It is formed by incomplete combustion. gaseous oxides of sulphur.
• It is a colourless, odourless gas.
• It
contain a triple bond and are fairly Photochemical Smog
polar, resulting in a tendency to bind It is also called Los Angeles smog.
permanently to haemoglobin molecules,. It occurs in warm, dry and sunny climate
displacing oxygen, which has a lower by the action of sunlight on unsaturated
binding affinity. hydrocarbons and nitrogen oxide.
• It is oxidising in nature.
Particulates
These are minute solid particles and liquid Tropospheric Pollution

e
droplets dispersed in air. e.g., mists, dusts, Presence
of undesirable solid or gaseous
smoke, fumes, etc.

nc
particles in the air Gaseous air pollutants
Disease Cause are S, N and C, HS, hydrocarbons, 0zone
Pneumoconiosis Due to inhalation of coal and other oxidants. Particulate pollutants
dust. are dust, mist, fumes, smoke, smog, etc.
Silicosis Due to inhalation of free
silica (Si0,).
ra Stratospheric Pollution
Black lung disease Found in workers of coal
mines.
• Stratospheric pollution means depletion
of ozone layer (ozone hole) by certain
White lung disease Found in textile workers.
Byssinosis compounds like chlorofluorocarbons
Due to inhalation of
(CFCs), oxides of nitrogen (which are
nt

cofton fibre dust.

released into upper atmosphere from
engines of supersonic transport planes).
Smog CCI4, halons and methyl chloroform also
It is a consequence of particulate pollution deplete 0zone layer.
ie

and is of two types • Depletion of ozone layer can cause skin

Classical Smog cancer, sunburn, ageing of skin, cataract
. It is or even blndness and also increases the
jm

also called London type smog.

• It is educing
evaporation of surface water.
in natue.
Industrial Names of Some Important Compounds
@

Industrial Name Chemical Name and Formula

Alum Potassium aluminium sulphate
(K_SO, Al(SO,) 24 H0)
Alcohol Ethyl alcohol (CHOH)
Baking powder Sodium bicarbonate (NaHCO)
Blue vitriol Copper sulphate (CuSO,5H,0)
Bleaching powder Calcium hypochlorite (Ca0Cl,)
Borax Sodiurm tetraborate decahydrate (NaB,0, 10H,0)
Brine or salt Sodiurm chloride (NaCl)
Calomel Mercurous chloride (Hg,Cl, or HgCi)
Caustic potash Potassium hydroxide (KOH)
Caustic soda Sodium hydroxide (NaOH)
Chile salt petre Sodium itrate (NaNO)
Chloroform Trichloromethane (CHCI,)
Dry
ice Solid carbon dioxide (CO)
412 GENERAL KNOWLEDGE~ General Science

Industrial Name Chemical Name and Formula

Epsum Magnesium sulphate (MgSO4 7H,0)
Glauber's salt Sodium sulphate decahydrate (Na SO, 10H0)
Green vitriol Ferrous sulphate (FeSO, 7H,0)
Gypsum Calcium sulphate (CaSO, 2H,0)
Hypo Sodium thiosulphate pentahydrate (Na SO3 5H,0)
Laughing gas Nitrous oxide (N,O)
Litharge Lead oxide (PbO)

e
Lunar castic Silver nitrate (AgNO,)

Magnesia Magnesiurn oxide (MgO)

nc
Marble or chalk or pearl Calciurm carbonale (CaCO,)
Marsh gas Methane (CH4)
Mohr's salt Ferrous ammonium sulphate,
-
(NH, ),S04 -FeSO, GH,0
ra
Mosaic gold Stannous sulphide (SnS)
Muriatic acid Hydrogen chloride (HCI)
Pearl ash Potassium carbonate (K,CO4)
nt

Plaster of
Paris
Calcium sulphate hemihydrate|CasO, Ho
Quicklime Calcium Oxide (CaO)
Redlead Lead peroxide (Pb04)
ie

Rock salt Sodium chloride (NaCI)

Ruby or sapphire Aluminium oxide, (AIO,)
jm

Sand Silicon dioxide (SiO,)

Sal ammoniac Ammonium chloride (NH.CI)

Slaked lime Calciurn hydroxide [Ca(OH)]

@

Spirit Methyl alcohal (CH,OH)

Soda ash Sodium carbonate (Na,C0,)
Vinegar Acetic acid (CHCOOH)
Vermilion Mercuric sulphide (HgS)
Washing soda Sodium carbonate decahydrate (Na,CO310H,0)
White vitriol Zinc sulphate (ZnSO4 7H,0)
GENERAL KNOWLEDGE~General Science 413)

Important Points
A candle blows off when covered because Chlorine is used for the purification of
it does not get Oxygen which helps in water, for synthesis of baking powder, etc.
burning. Na and K are highly reactive. They react
Phosphorus catches fire if kept in air but with air and water that's why, they are kept
it is unreactive with water, so it is kept in in kersene oil.
water. The Nobel Prize in Chemistry (2014)
When sugar is heated above 200°C, it Eric Betzig, Stefan W Hell, William E
decomposes into carbon and water. Moerner won the Nobel Prize in Chemistry

e
Therefoe, gets charred. (2014), for the smart work of surpassing
While making ice cream, salt is mixed the limitations of the light microscope,
with ice to reduce freezing temperature

nc
which has brought optical microscopy into
from 0°C to 5°C, This helps to freeze the the nano dimension. By this achievement,
Clea. scientists can visualise the roadways of
Lactose content of milk undergoes individual molecules in the living cells.
fermentation and changes into lactic acid Now this can be seen that how molecules
produce synapses between nerve cells in
ra
which on reaction with lactose fornms curd.
Zinc phosphide is used for killing rats and ne bain. Also they can find proteins
zinc chloride is used for coating furniture involved in different diseases like
Parkinson. Alzheimer and Huntington as
to prevent termites.
well as in fertilised eggs.
Calcium hydride (CaH) is called hydrolith.
nt

The Nobel Prize in Chemistry (2015) was

In flash bulb, magnesium wire is kept in awarded jointly to Tomas Lindahl, Paul
atmosphere of nitrogen gas. Modrich and Aziz Sancar. "for mechanistic
Barium sulphate is used in X-rays of studies of DNA repair".
ie

abdomen as barium meal. They have mapped, at a molecular level,

Silver and copper are best conductor of how cell repair damaged DNA and
electricity. Gold and silver are the most safeguard the genetic information. Their
jm

malleable metal. work has provided fundamental knowledge

Iron pyrites (FeS,) is known as fool's gold. of how a living cell function and can be
used for the developments of new cancer
Zinc oxide (ZnO) is known as flower of zinc
or chinese white and is used as white paint. treatment.
Nobel Prize in Chemistry 2016
Silver spoon is not used in egg food as it
@

turns black. The Nobel Prize in chemistry for 2016 has

Mercury is stored in iron pot. been awarded to Jean-pierre. Sauvage, sir
J. Fraser Stoddart and Bernars L. Feringa
Radium is extracted from pitch blende. for developing molecular machines.
Phosphine gas is used in Holme's signals. "Molecular machines will most. Likely to
Sea weeds contain iodine. Bones contain be used in the development of things such
57% calcium phosphate. as were materials, sensors and energy
Artificial perfumes are prepared from storage systems."
ethyl acetate.
 BIOLOGY
INTRODUCTION CHARACTERISTIC OF
• Biology is natural science LIVING ORGANISMS
concerned with the study of life and . They have cellular organisation and also
living organisms, i.e., plants and
respire, i.e., take in O, and evolve CO,.
animals. It is classified into wo part: .
Botany and zoology. Metabolism is one of the most important
characteristic feature of living organisnm. It

e
• Study of plants is called Botany and comprises two phases that are anabolism
study of animals is called Zoology. (constructive phase) and catabolism
Zoology and Botany are collectively

nc
(destructive phase.)
called Biology. The term Biology' •
They take nutrition for their growth.
was coined by Lamarck and •
Treviranus. They have tendency to reproduce.
•
The scientist who gave his thought They have the ability to respond to changes
ra in both internal and external environment
for the first time about the life of
plants and animals was Aristotle. i.e., they have sensitivity. Their survival
are maximum.
That's vhy he is known the Father • chances
as
of Biology. He is also known as the They move from place to place as animals or
Father of Zoology. Some bacteria. Plants cannot move but
nt

some novement can occur in plants.

• Theophrastus is known as Father of
Botany.
ie

The Cell
• The Cell is the basic structural and 2. Eukaryotic Cells (Eu = true, karyos =
jm

functional unit of all known living nucleus) These have a well defined
organisms. It is the smallest unit of nucleus and membrane bound cell
life and is often called the building organelles. These are present in
block of life. unicellular and multicellular plant and
@

• The branch of biology which deals animal cells.

with the study of cel, is called Differences between Prokaryotic
Cytology.
•
and Eukaryotic Cel
Robert Hooke coined the term cell Prokaryotic Cell
when he saw honey-comb like Eukaryotic Cell
structure in the section of cork. Simplest and Developed and
However, he only discovered cell wall. primitive in nature. comparatively complex in
nalure.
• The first living cell was discovered by
Leeuwenhoek. Lacks nuclear Nucleus is present with
envelope elaborate nuclear envelope
Types ofCells Membrane bound Mernbrane bound cell
These are of two types cell organelles are organelles are present.
1. Prokaryotic Cells absent.
(Pro=primitive, karyos=IUcleus) Single naked Many chromosomes are
These are primitive cells, lacking a chromosome present.
present.
well defined nucleus and most of
the other cell organelles, e.g., Cell division is Cell division ocCurs by
bacterial cell. direct. mitosis or meisis.
GENERAL KNOWLEDGE ~ General Science 415

Facts about Cell Mitochondria

• It was discovered by RAltman in
The largest known cells are unfertilised Ostrich
egg cells (size 6 inch diameter). 1880 and the term mitochondria
The smallest cell is of PPLO (Mycoplasma was coined by Carl Benda.
gallisepticum of size 0.1-0.3 um). It is bounded by a double memb
Human nerve cell is
the longest animal cel. rane. The inner membrane has
many folds, called the cristae. Fluid
Largest unicellular plant is Acetabularia (10 cm)
and animal is Amoeba (1 mm). (called matrix) is present on interior,
The largest human cell is the female ovum and which contains many enzymes and
coenzymes. It isa semi- autonomous
the smallest human cell is the red blood cell.
(can form its own copies) organelle

e
and is called power house of the
Parts of Cell and their cell because in it, stepwise oxidation

nc
of fuel occurs which results in
Functions release of chemical energy. This
A typical cell consists of cell wall and energy is stored in the form of ATP
protoplasm.
Plastids
ra
Protoplasm of Cell
These are present only in plant cells
It is the living fluid matter present inside the
and are of three types- chloroplasts
plasma membrane. The fluid present outside (green), leucoplasts (white) and
the nuclear membrane is called cytoplasm and chromoplasts (of various colours
nt

the fluid present inside the nuclear membrane except green). Chloroplast is the site
is called nucleoplasm. Deutoplasm is the of photosynthesis as it contains
non-living matter of the cell. chlorophyll, while leucoplasts are
Cell Wall storage plastids. Chloroplast is called
ie

the kitchen of the cell.

It is present in plant cells, bacteria, fungi, algae
and some archaea. It is composed of cellulose The red colour of tomatoes is due to
in plants and chitin in fungi. It is non-living. Its the presence of lycopene pigment,
jm

i.e., chromophore.
main function is to provide shape and rigidity to
the cell. The colour of carrot is due to
carotene pigment.
Plasma Membrane Endoplasmic Reticulum
The cell is enclosed by a thin membrane called
@

the cell membrane or plasmalemma. It is It was discovered by KR Porter. These

composed of proteins and phospholipid are hollow membranous system having
molecules. It is elastic, living and selectively ribosomes (thus called Rough ER) or
no ribosomes (thus called Smooth
permeable, i.e., provide passage for various
substances. ER).
Nucleolus Nitochondria Rough endoplasImic reticulum is
Nucleus
Ribosomes Cytoskeleton the site of protein synthesis, while
sImooth endoplasmic reticulum is the
site of synthesis of steroids and
Rough
endoplamic
Golgi detoxification.
apparalUs
retioulum
Golgi Apparatus
CeliiolE It was discovered by Camillo Golgi. It
PoronGomo HilTsmic is made up of sac-like flattened
iim
PESIla structures and play an important role
in secretion, transportation and
Structure of the Cell acrosome formation.
 416) GENERAL KNOWLEDGE~ General Science

Nobel Prize in Physiology and Chromosome

Medicine 2013 Chromosome is thread-like structure,
The Nobel Prize in Physiology or medicine 2013 vwas found in the nucleus. Bead-like
awarded jointly to James E Rothman, Randy W structures found on chromosome are
Schekman and Thomas C Sudhof for their called genes, which are made up of
DNA and are the carrier of genetic
discoveries of machinery regulating vesicle traffic, a
major transport system in our cells. In general, we information from generation to
call it Golgibody. Randy Schekman discovereda set generation. Chromosomes are units of
of genes that were required for vesicle traffic.
inheritance. In some virUses e.g.
retrovirus, RNA is the genetic
James Rothman discovered machinery that allowS material.

e
vesicle to fuse with their targets to deliver the
stored matter. Differences between
Plant and Animal Cell

nc
Ribosomes Plant Cel Animal Cell
It Cell wall is usually
Ribosomes were discovered by GE Palade. has cell wall.
absent.
These are minute, non-membranous particles,
composed of RNA and protein. 70 S type of Plastids are found. Plastids are usually
ra
ribosomes are found in prokaryotes, while 80 S absent.
type in eukaryotes. These are the site of protein Centrioles and Centrioles and
synthesis. centrosome are centrosomes are
absent. found in all cells.
A big vacuole is Vacuole is absent
nt

Lysosomes present. or very small in

• Lysosomes were discovered by de Duve. size.
These are polymorphic organelles having
hydrolytic enzymes. These enzymes function Nucleic Acids
ie

at (acidic) pH ~5. These are sometimes genetic

These contain the
called suicidal bags of the cell. instructions used in the development
• Lysosome helps in carcinogenesis, i.e., and functioning of all known living
jm

conversion of a normal cell into cancerous organisms.

cell. These are of two types : DNA and RNA.
CentroSome Deoxyribonucleic
It was discovered by T Boveri. It is composed of
Acid (DNA)
@

two set of centrioles and participate in the

DNA was discovered by James
formation of mitotic spindle during cell division.
D Watson and Francis Crick, who
Vacuoles got Nobel Prize for this discovery.
These are non-iving reservior, bounded by It is a long polymer made from
a membrane called tonoplast. Pigment repeating units called nucleotides.
anthocyanin is present in the cell vacuole, Each nucleotide consists of a
which provide colour flowers. It stores toxic nucleoside (i.e. nitrogenous base
metabolic waste and helps in osmoregulation. and deoxyribose sugar) and a
phosphate group. joined together by
Nucleus phosphodiester bonds.
It was discovered by Robert Brown. It contains It has four bases, i.e. adenine,
nucleoplasm, nucleolus and chromatin guanine, cytosine and thymine.
material. Nucleolus is rich in protein and RNA. • Adenine and guanine are the
All this material is covered up by a nuclear purine bases; cytosine and thymine
membrane. Chromatin is the controlling are pyrimidine bases.
centre of cell as it form chromosomes.
GENERAL KNOWLEDGE~ General Science 417

Ribonucleic Acid (RNA) It is of two types - Mitosis and Meiosis

•

• It is also made up of a long chain of (i) Mitosis It 0CCUrS in unicellular

nucleotides. organism during asexual reproduction.
• Each nucleotide consists of a Each mitotic cell division results in the
formation of two daughter cells having
nitrogenous base, a ribose sugar, and
a phosphate group. number of chromosomes equal to the
parent cell.
• It
contains uracil in place of thymine. Tumour or cancer is result of
• RNA is of three
types uncontrolled mitosis.
mRNA (messenger RNA) (ii) Meiosis It occurs in reproductive cells
rRNA (ribosomal RNA)
and is called reduction division because of

e
tRNA (transfer RNA) the presence of single set of chromosomes
These three RNA's take part in protein (i.e., half of the parent chromosomes). It

nc
synthesis. results in the formation of four daughter
cells.
Cell Division • Exchange of genetic material occurs
• It is the process by which a cell between chromatids (branches of
increase in number. It is essential for chromosome) of a diploid set during
ra
the growth, development and repair pachytene stage of meiosis and is known as
of the body. Crossing over.

Differences between DNA and RNA

nt

DNA RNA
It usually ocours inside nucleus and in some Very little RNA occurs inside nucleus. Most of it
cell organelles like mitochondria and is found in the cytoplasm.
chloroplast.
some
ie

DNA is the genetic material exoept in ANA is not the genetic material except in
viruses. certain viruses, e.g, HIV, reovirus.
It is double stranded with the exception of RNA is single stranded with the exception of
some viruses like x 174. some viruses, e.g., double stranded in To, T,,
jm

T, bacteriophage.
DNA shows regular helical coiling. There is no regular coiling except in parts of
ANA.
It contains deoxyribose sugar. Itcontains ribose sugar.
Nitrogen base thymine occurs in DNA along Thymine is replaced by uracil in ANA. The
@

with other three i.e. adenine, cytosine and other three are adenine, cytosine and guanine.
guanine.
It
replicates to form new DNA molecules. It cannot replicate itself except in RNA-ANA
viruses.
DNA controls heredity, evolution, melabolis, ANA controls only protein synthesis.
structure and differentiation.

BIOMOLECULES some others are exceptions. So this

Biomolecules are the substances that definition has been changed. According to
are essential for a living being to modern definition, these are the
perform the basic functions, polyhydroxy aldehydes and ketones or their
e.g., carbohydrates, proteins, lipids derivatives.
(fats), nucleic acids and vitamins. • These are the source of energy and about
50-75% energy is obtained by the oxidation
Carbohydrates
.
of carbohydrates.
It was believed that these are the The main end product of carbohydrate
organic compounds which have carbon, digestion is glucose, which is called blood
hydrogen and oxygen in the ratio of sugar. It oxidises to give energy along with
1:2:1 but starch (CGHyoO5),, and CO, and H,0.
 418 GENERAL KNOWLEDGE~General Science

• I gm glucose provides about 17 kJ energy (S). These form l15% part of human body.
or 4.2 kcal energy. Snake venom, ricin of castor and bacterial
.
Carbohydrates are better fuel as toxins are proteinaceous in nature. Main
CoImpared to proteins and fats as they sources of protein are groundnuts,
decompose to give energy. soyabean, pulses, fish etc.
. readilysources
Main of carbohydrates are wheat,
maize, rice, potato etc.
Function of Proteins
The carbohydrates are categorised into These are important for the growth and
following three types repair of the body (75% of our body is
protein only). However, in the
Monosaccharides deficiency of carbohydrates, these acts
as the source of energy. Protein also

e
•
These are simple sugars, which cannot be control the development of genetic
hydrolysed further, e.g., ribose, glucose,
characters.

nc
fructose, galactose etc.
• In Deficiency of protein causes
human beings, blood glucose level is Kwashiorkor (a disease in which hands
100-120 mg/mL. Extra glucose, if any, is get
and legs of children slimmed and the
converted into glycogen in the liver by a comes out) and Marasmus (a
process called glycogenesis. stomach
ra disease in which muscles of children are
D-iructose is the sweetest of all sugars loosened). Kwashiorkor occurs in
and is found in fruit juice, honey etc. children between I to 5 years of age and
marasnus in children below Iyear.
Oligosaccharides
nt

• They release 2-10 monosaccharides on Lipids (Fats)

hydrolysis, like disaccharides, e.g. • These are also the compounds of carbon
Sucrose, lactose maltose etc and (C), hydrogen (H) and oxygen (0)
trisaccharides, like raffinose etc. Chemically, these are the ester of
ie

• Sucrose is also called invert sugar. It glycerol and fatty acids. These are
gives glucose and fructose when present in cytoplasm, cell wall etc.
subjected to hydrolysis. The main source of fats are ghee, butter,
jm

almond, cheese, egg yolk, meat,

Polysaccharides soyabean etc.
• They release more than ten • Fats are digested by enzymes called
monosaccharides on hydrolysis. These lipases in the small intestine. Generally.
are non-sugars, i.e., do not have sweet at 20°C, these are in solid state but if
@

taste, e.g., cellulose, glycogen and starch. their state is liquid at this temperature,
• Cellulose is found in plant cell wall and is
these are termed as oils.
digested by ruminants (like cow, goat, Fatty acids are of two types- Saturated
buffalo, etc), but not by carnivorous or and Unsaturated. Saturated fatty acids
omnivorous animals like human beings. are found in coconut oil and palm oil,
Thus, it acts as roughage in case of while unsaturated fatty acids are found
human beings. in fish oil and vegetable oil.
• Excess of saturated fats raises the level
Function of Carbohydrates of blood cholesterol and may cause
• Carbohydrates provide energy, that acts
as reserve food, help in the synthesis of arteriosclerosis. This may lead to
heart attack.
nucleic acid and form exoskeleton of
animals. Excessive intake of carbohydrate
Function of Lipids
results in digestive problems and obesity. The
main functions of lipids are
• These provide twice the energy than
Proteins that from carbohydrates.
These are found in all living cells. These are
the compounds of carbon (C), hydrogen These remain under the skin and
(H),oxygen (0), nitrogen (N) and sulphur prevents the loss of heat from the body.
GENERAL KNOWLEDGE~General Science 419

These are divided into two groups

Malnutrition Effects
• 1. Fat soluble vitamin, viz. vitamin
Deficiency of fat results in dryskin and weight
A, D, E and K.
loss.
• If fat s in excess, the body gets fatty and 2. Water soluble
vitamin-B and C.
vitamin, viz.
result in several heart diseases and high
blood pressure. Vitamin-B1g contains cobalt.
• The skin fat, in case of whales and seals, Vitamin-D is synthesised in our skin
by the action of ultraviolet rays of
forms a thick layer called the blubber. It acts
as reserve food and also maintains the body the sunlight. Vitamin-K is
temperature. synthesised in our colon by the
bacteria.

e
Vitamin Water soluble vitamins normally do
• It was first discovered by FG Hopkin. not show hypervitaminosis (this

nc
However, the term vitamin was coined by C disease occurs due to excess intake
Funk. of vitamins) as excess of these
vitamins is normally excreted
• Vitamin is an organic compound, which through urine.
cannot besynthesised in sufficient quantities
In halanced diet, all the important
ra
by an organism and must be obtained from
nutrients (like carbohydrate,
the diet.
protein, fats, vitamins etc.) are
• They provide no calories, they only regulate available in sufficient quantity.
chemical reactions 0cCurring in the
nt

metabolism of the body.

Vitamins, their Deficiency Diseases and Sources
Vitarmin Chemical Name Deficiency Disease Source
ie

Vitamin-A Retinol, Night-blindness(Nyctalopia) Orange, green vegetables,

, Hyperkeratosis,
carotenoids carrols, pumpkin, squash and
Keratomalacia spinach.
Vitarmin-D Calciferol Rickets and Osteomalacia Fish, eggs, liver and
jm

mushrooms.
Vitamin-E Tocopherols, Infertility Many fruits and vegetables.
tocotrienols
Vitamin-K Phylloquinone Non-clotting of blood Green vegetables
@

Vitamin-B, Thiamine Beri-beri, Oatmeal, rice, vegetables,

Wernicke-Korsakoff cauliflower, potatoes, liver
syndrome and eggs.
Vitanin-B, Riboflavin Cracking of skin, reddish Dairy products, bananas,
eye, oracking of tongue popcorn and green beans.
Vitamin-B Niacin and Pellagra,Glossitis Meat. brocooli and avocados.
nicotinic acid
Vitarmin-B, Pentothenic acid Prermature greying of hair Meat, fish, eggs, many
(Achromolrichia), vegelables, mushrooms.
Vitamin-B Pyridoxine Dermatitis, anaemia, mental Meat, vegetables, tree nuts
disorder and bananas.
Vitarmin-B, Biotin Dermatitis, enteritis and Raw egg yolk, liver, peanuis
anaemia and vegelables.
Vitarmin-B, Folic acid, folinic Megaloblastic anaemia and Leafy vegetables, pasta,
acid birth defects. bread, cereal and liver.
Viltanin-B2 Cyanocobalanin Pernicious anaemia Meat and other animal
(contains cobalt) products.
Vitarnin-C Ascorbic acid Scurvy (Sailer's disease) Peppers, citrus fruits.
420) GENERAL KNOWLEDGE~General Science

Biological Evolution
Origin of Universe Organic Evolution
• The universe is made up of matter and More and more creation of organisIn by
energy. Scientists believe that it was gradual changes from low category animal to
formed about 10 to 13 billion years ago higher animal is called organic evolution.
as a vast, dense, red-hot and rotating There ae several evidences regarding
gaseous cloud of cosmic dust called the organic evolution.
"primaeval matter or 'ylem'.
• hypothesis
Evidences from morphology

e
Two i.e., Big -Bang
(universe formation through a very big and anatomy
explosion) and Nebular (universe On the basis of morphology (outer

nc
formation by the condensation of appearance) and anatomy (inner structure),
gaseous cloud) were given to explain several evidences have been described as
origin of Earth. follows

ORIGIN OF LIFE Homologous Organs

ra
• The organs which are similar in basic
.
Life originated on Earth about 3.5 structure and origin but dissimilar in
billion years ago. Some philosophical function are called homologous organs,
theories like special Creation, e.g., wings of bat, cat's paw, front foot of
spontaneous generation, Biogenesis,
nt

horse, human's hand and wings of birds.

panspermia (life originated in the form
of pansperms from some unknown These show divergent evolution.
part of the universe) or cosmozoic and Analogous
catastrophism (ife orginated suddenly
Organs
ie

from inorganic matter) were given (Homoplastic)

explain origin of life. The organs which are similar in shape and
. function but dissimilar in their origin and
The first scientific account of the
development. e.g., wings of insects, birds
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origin of life was given by Russian

scientist AI Oparin in his book 'Origin and bats, eyes of octopus and mammals.
of life'. They show convergent evolution.
• The primitive atmosphere contained
hydrogen, methane, ammonia and VestigialOrgans
@

water vapour. In it, oxygen and ozone • These are degenerate, non-functional
were absent. Thus, it was believed that organs which were functional earlier.
life is originated from inorganic• Human body has been described to possess
substances by a series of complex about 90 vestigial organs. Some of these
reaction. are muscles of ear pinna, canine teeth and
• Hydrogen atoms were most numerous third molar teeth, body hairs, vermiform
and most reactive in the primitive appendix, nictitating membrane of eye,
atmosphere. First, these combined caudal vertebral (coccyx or tail bone) etc.
with all available oxygen atoms,
forming water and leaving no free AtaviSm or Reversion
Oxygen atoms. Thus, the primitive It is the sudden reappearance of some
atmosphere was 'reducing unlike the ancestral features. Appearance of thick body
present 'oxidising' atmosphere. This hair, large canines, monstral face, short
was also supported by Miller and Urey temporary tails, extra nipples etc are
in 1953. examples of atavism.
• In Miller-Urey a
experiment, mixture Evidence
of water, hydrogen, methane and
from Connecting
ammonia was cycled through an Links
apparatus and the organic compound, Connecting link is one which exhibit
amino acids were obtained. characteristics of more than one groups.
GENERAL KNOWLEDGE~ General Science 421

Intermediate Forms between Two Mutation Theory

Groups of Organisms • Hugo de Vries proposed the theory
Organism Connecting Link Between of mutation, while working
Oenothera lamarckiana plant.
Virus Living and non-living .
Mutations are discontinuous
Euglena (Protozoa) Plants and animals variations.
Proterospongia Protozoa and Porifera • Mutations are due to changes in
(Protozoa) chromosomes, genes and DNA.
Peripatus (Arthropoda) Annelida and Arthropoda These may or may not be imherited.
Synthetic Theory

e
Neopilina (Mollusca) Annelida and Mollusca
Balanoglossus Non-chordala and According to it, the fiue basic factors

nc
(Chordata) Chordata are
Dipnoi (Lung tish) Pisces and Amphibia 1. Gene mutation
Archaeopteryx (Aves) Reptiles and Aves 2. Changes in chromosome
Prototheria Reptiles and Marnmalia structure and number
(Marnmalia) 3. Genetic recombination
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4. Natural selection
THEORIES OF 5. Reproductive isolation

EVOLUTION First three factors are responsible for

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genetic variablity.
Lamarckism (18o9) Devonian period is known as Age of
• Jean-Baptistede Lamarck gave the idea that fishes.
an organism can pass on characteristics that it
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Mesozoic era is knOwn as Age of

acquired during its lifetime to its offspring Reptiles.
(also known as heritability of acquired
characteristics). Coenozoic era is known as Age of
Mammals.
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• Lamarck's theory of evolution was published

in Philosophie Zoologique and had four
propositions, viz Classification of
1. Living organisms and its parts tend to Organisms
increase in size due to internal force of life.
@

In Linnaeus time, a two kingdom

2. Formation of new orgars is the result of a system of classification with Plantae
new need and new involvement. and Animalia kingdom was developed.
3. Individuals lose characteristics that they do The system díd not distinguish
not require (Or use) and develop between the eukaryotes and
characteristics that are useful. prokaryotes, unicellular and
4. Individuals inherit the traits of their multicellular and photosynthetic
ancestors. organisms.

Darwinism (1859) Five Kingdom System

• Darwin's theory of evolution uas Origin of RH Whittaker (1969) proposed a five
Species by Natural Selection. kingdom classification. The lingdom
•
The theory consists of five propositions. they named were Monera, Protista, Fungi,
Plantae and Animalia.
are
1. Overproduction or enormnous fertility
Classification of
2. Struggle for existence
Animalia Kingdom
3. Variation and heredity
Storer and Usinger classified
4. Survival of the fittest or natural selection
animals into following phyluns
5. Origin of species.
 22 GENERAL KNOWLEDGE~ General Science

Characteristics of the Five Kingdoms

Character Monera Protista Fungi Plantae Arimalia
Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic
Cell wall Non-cellulosic Present in some Present Present Absent
Nuclear Absent Present Present Present Present
membrane
Body Cellular Cellular Multicellular/ Tissue/ Tissue/
organisation loose tissue organ organ/organ
system
Mode of Autotrophic and Autotrophic and Helerotrophic Autotrophic Helerotrophic

e
nutrition helerotrophic helerotrophic
Examples Bacteria Amoeba Acholrophylus, Multicellular Multicellular

nc
archaebacteria Euglena heterotrophic eukaryotic animals
cyanobacteria Dinoflagellates fungi planls
and some
primitive fungi ra
Phylum--Protozoa
.
Phylum- Platyhelminthes
These are unicellular animals, i.e., made Animals of this phylum have
up of only one cell. alimentary canal with single opening,
• In these, all the metabolic activity like anus is absent.
nt

digestion, respiration, excretion and . Excretion takes place by flame cells.

reproduction takes place in unicellular There is no skeletal system such as,
body.
respiratory system, circulatory system
• Respiration and excretion take place etc.
ie

through diffusion. These are hermaphrodite animals

e.g., Anoeba, Plasmodium, Euglena etc. (males are not separated from
females).
Phylum-Porifera
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e.g., Planaria, Liver fluke, Tape worm

• These are found in marine water and have etc.
porous body. The pores are called ostia.
are multicellular animals. Phylum-Aschelminthes
. These
Their skeleton is made up of minute These are long, cylindrical,
@

calcareous or siliceous spicules. unsegmented worms.

e.g., Sycon, Sponge etc. Their alimentary canal is complete in
which mouth and anus both are
Phylum-Coelenterata present.
•
These are aquatic animals, have thread-like• There is no circulatory andrespiratory
structures called tentacles around the system but nervous system is
mouth which help in holding the food. developed. Excretion takes place
• They have specialised cnidoblast cell to through protonephridia.
help in catching the food. They are unisexual.
• Phenomenon of polymorphism (many Most forms are parasitic but some are
forms) and metagenesis (alternation of free living in soil and water.
generation) are associated with e.g., Ascaris, Threadworm, etc.
coelentrates.
e.g., Hydra, Jelly fish, Sea Anemone etc. Threadworm is found mainly in the
anus of child. Due to which children
• Hydra has a tendency of xegeneration of
feel itching and often vomits. Some
body organs. children urinate on the bed at night.
GENERAL KNOWLEDGE ~ General Science 4423

Phylum-Annelida • Excretion takes place through kidneys.

• e.g., Pila, Aplysia (Sea rabbit), Doris (Sea
Their body is long, thin, soft and
metamerically (truly) segmented. lemon), Octopus (Devil-fish), Sepia
•
(Cuttle-fish).
Alimentary canal is well-developed.
• These are Eyes of octopus are similar to chordate
the first to have proper organ eyes.
. systems. system
Nervous is normal and blood Phyluum-
(called haemolymph) is red (iron rich
Echinodermata
• All the animals in this group are marine.
haemoglobin).
• Their blood flovs in closed vessels. They have water vascular system.
Brain is not developed in nervous

e
• Like
in earthwornm, there are five pairs of System.
blood vessels called as heart. • They have a special capacity of

nc
• They respire through skin,
in some regeneration.
animals respiration takes place through
coelom.
•
These are the only invertebrate animals
• which contain proper bone like
Excretion by nephridia. structures (ossicles).
• They move through setae made up of
ra e.g., Star fish, Sea urchin, Sea cucumber
chitin. etc.
e.g. Earthworm, Nereis, Leech etc.
Phylum-Chordata
.
Phylum-Arthropoda They have notochord. A dorsal hollow
nt

• Arthropoda is the largest phylum tubular nerve cord and paired

pharyngeal gill slits at some stage of their
(contains maximum number of animals
life span.
and its existence is recorded for •
maximum period over the Earth). In advanced forms, notochord changes
ie

• to vertebral column, nerve cord develops

Jointed leg is their main feature. to brain and spinal cord and pharyngeal
•
Their body is divided into three gill slits to structures of jawattachment.
jm

parts-head, thorax and abdomen. • This phylum is sub-divided into two

• Circulatory system is open type. sub-phylum, i.e., Protochordata and
Cockroach's heart has 13 chambers. Vertebrata.
• Trachea or book lungs, body surface are Some main classes of phylum- Chordata
respiratory organs. are as follows
@

e.g., Cockroach, Prawn, Crab, Bug, Fly,

Mosquito, Bees, etc. Pisces
Insects generally have six feets and four • These are aquatic animals (cold-blooded
wings. animals). Their heart pumps only
a
Ant is social animal which reflects impure blood and have two chambers.
division of labour. • Respiration takes place through gills.
a
Termite is also social animal which e.g., Trygon, Scoliodon, Torpedo etc.
lives in colony.
Amphibia (First land
Phylum-Mollusca vertebrates)
•
Their body is soft and divided into head • These are found both on land and water.
and muscular foot.
• All of them are cold-blooded.
Mantle is always present in it, which •
secretes a hard calcareous shell. Respiration takes place through gills,
•
skin and lungs.
Their alimentary canal is well
•
developed. They have three chambered heart.
e.g., Frog, Necturus, Toad, lcthyophis,
• Respiration takes place through gills or
ctenidia. Blood is colourless. Salamander.
 424 GENERAL KNOWLEDGE~General Science

Reptilia (First true land Mammalia is divided into three

sub-classes
vertebrates) •
Prototheria It lays eggs, e.g.,
•
These are crawling animals. Echidna.
• These are cold-blooded and contains two • Metatheria It bears the immature
pair of limbs. child, e.g., Kangaroo.
• The skeleton is completely flexible. • Eutheria It bears the well developed
• Respiration takes place through lungs. child, e.g., Humans.
• They have 3- chambered heart (four They give birth to young ones, but
Echidna and Platypus are the egg
chambered in crocodile). laying mammals.

e
•
Their eggs are covered with shell made up
of calcium carbonate. SYSTEMS OF

nc
e.g., Lizard, Snake, Tortoise, Crocodile, HUMAN BODY
Turtle, Sphenodon etc.
. Cobra
is the only snake which makes The
Integumentary System
human skin (integumentary) is
nests.
ra composed of a minimum of three major
Heloderma is the only poisonous lizard. layers of tissue, the epidermis, dermis
Sea snake is also called Hydrophis and hypodermis.
belcheri. It is the vorld's most poisonous
snake. Epidermis
nt

The top layer of skin is made up of

Aves (Aerial Vertelbrates epithelial cells and does not contain
Birds) blood vessels.
• The animals of this group are
ie

warm-blooded tetrapod vertebrates with

Dermis
flight adaptation. • Itgives elasticity to the integument,
allowing stretching and conferring
•
Their fore-feet are modified into wings to
jm

flexibility, while also resisting

fly.
• They espire through lungs. distortions, wrinkling and sagging.
• Nails grow l mm per week on an
• Birds have no teeth, beak helps in feeding.
. They average.
have a single ovary and pneumate. Protein, keratin
stiffens epidermal
@

bones. e.g., Crow, Peacock, Parrot etc. tissue to form inger nails.
Flightless birds are Kiwi and Emu.
Largest bird is Ostrich. Hypodernmis
• It is made up of adipose tissue.
Smallest bird is Humming bird.
-

Largest zoo in India is Alipur (Kolkata) It performs several inportant functions

and the largest zoo of the world is Cruiser 1. Protect against invasion by
National Park in South Africa. infectious organisms.
2. Protect the body from dehydration.
Mammalia 3. Maintain homeostasis.
• These are warm-blooded animals. 4. Act asa receptor for touch, pressure,
. pain, heat and cold.
Tooth comes twice in these animals
(diphyodont). 5. Protect the body against sunburns by
•
There is no nucleus in their red blood cells secreting melanin.
(except camel and llama).
in 6. Generate vitamin-D through
• Skin of mammals contains hair. exposure to ultraviolet light.
• External ear
is present. 7. Store water, fat, glucose and
vitamin-D.
GENERAL KNOWLEDGE ~ General Science 425

Animal Nutrition and and oxygen and constitute about 4% of

total body weight.
Digestion • Milk, eggs, meat,
fruit, food, vegetables
Animals are not able to snthesise their etc are the sources of minerals.
own food. therefore they obtain it from Minerals are of two types
outside environment for their nutritional 1. Macronutrients These are required in
requirements.
large amount, e.g., calcium (Ca),
Mineral phosphorus (P), potassium (K) etc.
.
Nutrients 2. Micronutrients These are required in
These are metals, non-metals and their very small amount (less than l g), e.g.,
salts other than the four iodine (1), iron (Fe), zinc (Zn)etc.

e
elements-carbon, hydrogen, nitrogen
Minerals and their Functions in the Body

nc
Mineral Major Food Source Uses Deficiency Disease
Macronutrients
Calcium Mik, cheese, bread Muscle contraction, nerve Tetany and rickels.
(Ca) and vegelables. action, blood clotting and
ra
the formation of bone.
Phosphorus Cheese, eggs P Bone and tooth formation, Tetany and riokels.
(P) nuts and most energy transfer from foods,
DNA, ANA and ATP
formation.
nt

Sulphur (S) Dairy producls, meat, Formation of thiaine, Disturbed prolein

eggs and broccoli. keratin and coenzymes. metabolism
Potassium Polatoes, meat and Muscle contraction, nerve Nervous disorder, poor
(K) chocolate. action, active transport. Muscles leading to
paralysis.
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Sodium (Na) Any salted food, meat, Muscle contraction, nerve Nervous, depression,
eggs and milk. action and aclive transport. muscular cramps, pH
disbalance
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Chlorine (CI) Salted food and Anion/cation balance and Loss of appetite muscle
seafood. gastric acid formation. cramps.
Magnesium Meat, chocolate and Formation of bone, Irregularity of metabolism.
(Mg) green vegelable formation of coenzyrmes in
cell respiration.
@

Micronutrients (Trace Elements)

Iron (Fe) Liver, kidney, red Formation of haemoglobin, Anaermia and low immunity.
meat, cocoa powder myoglobin and cytochromes.
and water cress
Fluorine (F) Water supplies, tea, Resislance to tooth decay. Weak teeth (if present in
sea food, meat, liver excess causes mottling of
and beans. (teeth)
Zinc (Zn) Meat, liver and beans. Enzyme activation and Anaernia, relarted growth,
carbon dioxide transport. weak immunity and fertiltly.
Copper (Cu) Liver, meat and fisth. Enzyme, melanin and Anaemia, weak blood
haemoglobin formation. vessels and connective
tissues.
lodine () Seafood, iodised salt Thyroxine production Goitre
and fish.
Manganese Tea, nuts, spices and Bone development and Irregular growth of bones
(Mn) cereals. enzyme activation. and connective tissues.
Chromium Meat and cereals. Uptake of glucose. Irregular metabolism.
(Cr)
Cobalt (Co) Meat and yeast. Synthesis of vitarmin- B, Anaemia
formation of red blood cells
 426) GENERAL KNOWLEDGE~ General Science

Water • The number of teeth are different in

different animals. These are represented
About 70% of the human body consists of by dental formula as
water. Tvo-third of water exists inside
cells, the other one-third is outside the
ICPm M- Upper half jaw
1C Pm M- Lower half jaw
cells in tissue fluid and blood plasma. It is
essential for digestion, transportation, Where, I-Incisors,C-Canines,
excretion and to regulate body Pm -Premolars and M-Molars.
temperature. • Premolars and molars are called cheek
Many factors affects the health of human teeth. Milk teeth do not include molar
body. One of them is adulteration. teeth.
In humans, first teeth come in between

e
•
Food Adulteration 6 and 8 months. By the age of 6, milk
Addition of undesirable, cheap and teeth are gradually replaced by permanent

nc
harmful substances in the food is called teeth.
food adulteration. • Hardest part in the body is tooth enamel.
Indian Standards Institution (1SI) Mark
and Agmark (Agricultural marketing) are
• In elephants, the tusks are the incisors of
upper jaw.
given by the Bureau of Indian Standards
ra
after testing the purity and quality of Maximum number of teeth are present in
material and food respectively. horse and pig.
Some Common Adulterants Dental Formulae of
in Food Some Mammals
nt

Food Item/Stuff Adulterant Marmmal Dental Total Number

Milk, Water and urea Formula of Teeth
curd and
cheese Man (child) 2102/2102 x 2 20
ie

Sweets Saccharin, harmful colour Man (adult) 2123/2123 x 2 32

Ghee Vanaspati and animal Horse 3143/3143 x 2 44
fats Dog 3142/3143 x 2 42
Stones, sand and grit 0033/3133 x 2
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Cereals Cow and 32

Dhania powder Powdered horse dung Sheep
Haldi powder Lead chromate Cat 3131/3121 x 2 30
Pulses Melanil yellow Rabbit 2033/1023 x 2 28
Edible oils Argemone oil Mouse 1003/1003 x 2 16
@

Black pepper Papaya seed

Tongue
• Saliva, secreted by the salivary glands, is
HUMAN DIGESTIVE mixed with the chewed food by the
SYSTEM tongue.
The human digestive system consists of • Tongue also contains taste buds due to
alimentary canal and digestive glands. which we sense bitter, sou, salty or sweet
The alimentary canal consists of mouth, taste.
(having teeth and tongue) oesophagus,
stomach, small intestine and large
intestine.
Bitter
Teeth
• Sour Sour
With the help of teeth the food is
chewed. Teeth are of four types
Incisors (for cutting) Salt Salt
Canines (for tearing) Sweet
Premolars (for chewing) Taste Areas on the Human Tongue
Molars (for chewing and grinding)
GENERAL KNOWLEDGE ~General Science 427

Functions of the Complete digestion process takes place in

following four steps
Digestive System
Splitting of complex food materials into .Ingestion of Food
simpler molecules by hydrolysis so that Ingestion takes place in buccal cavity.
they can be easily absorbed by
intestine is the main function of
the. aliva Jubricates the food and binds the food
particles together to form bolus.
digestive system.
. Salivary gland have starch spitting enzyme
Man and other animals have holozoic ptyalin.
nutrition i.e., solid form of food. • Parotid gland is the largest salivary gland.

e
Oral cavity
Tongue
-Pharynx
Parolid gland

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Salivary Submandibular Oesophagus
Gland gland
Sublingual -Cardiac orifice
gland
Liver
ra
Ascending portion Pyloric
sphincler Stomach
of large intestine Gall bladder.
Pancreas
Ileum
nt

of small
intestine -Srmall
inlestine Duodenum of
Large small intestine
intesline
Caecum
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Appendix
Anus
Rectum
Human Digestive System
jm

Digestion of Food Digestion in Duodenum

Digestion in Mouth Chyme moves to duodenum.
•
•
Food is mixed with bile (liver) to breakdown
In mouth, salivary amylase acts on
@

starch. fats into smaller globules.

• Trypsin acts upon proteins and break them
Plyalin
Starch Maltose into polypeptides. Amylase converts starch
(Complex form) (Simple form) into simple sugar.
.
Lipase convert fats into fatty acids and
glycerol.
Digestion in Stomach
•
The food passes down through the Digestion in Intestine
oesophagus into stomach. • Food passes into ileum and mixes with
• Now food is mixed with gastric juice intestinal juice, where
and hydrochloric acid which Maltase converts maltose into glucose
disinfect the food and creates acidic Lactase converts lactose into glucose
mediun. and galactose
• Pepsin digests proteins and converts Sucrase converts sucrose into glucose and
them into peptones. fructose
• Rennin convert milk into curd. Trypsin digests the peptides into amino
• Digested food now is called chyme. acids
 428 GENERAL KNOWLEDGE~ General Science

Absorption and Assimilation of Pancreas

Digested Food • It is the second-largest gland of the
• human body and contains islets of
Ileum's internal surface has finger-like
folds called villi. Langerhans and exocrine part secreting
• It helps in absorption of food. enzymes for carbohydrate, protein and
• Intestinal juice is alkaline in nature. nucleic acid digestion.
• pH of saliva, gastric juice, pancreatic
• The most common is the B-cells, which
secretes insulin, a hormone deffciency
juice and intestinal juice is respectively
6.8, 2.0, 7.0 and 8.5. of which causes diabetes melitus.
• Excess of insulin causes hypoglyaemia,

e
Ejection of Unwanted Food in which one loses the reproducing
• Digested food passes into large intestine. capacity and vision.

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• Large intestine cannot absorb food, but
absorbs much of the water.
Tntestinal Gands
. Crypts of Lieberkuhn and Brunner's
The remaining semi solid waste is Called olands are intestinal glands and secrete
faeces and is passed into rectum. intestinal juice which is alkaline in nature.
• It is expelled out through anus.
ra
Roughage RESPIRATORY
• Roughage is another term for dietary SYSTEM
fibres e.g., Natural food, dalia etc. Respiration is a catabolic process in
nt

.
It does not provide energy but only helps which the respired oxygen is Ised in the
in retaining water in the body. oxidation of food resulting in the elease of
energy. It brought about by respiratory
organs.
SOME DIGESTIVE
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GLANDS Respiratory Organs

of Some Animals
Liver
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•
Respiratory Animal
It is the largest gland of the human body organ
and secretes bile juice, which is stored in
gall bladder. Lungs Reptiles like lizards,
• mammals like man, camel,
It regulates the quantity of glucose in the
@

cattle, etc.
blood by converting extra glucose (if any)
into glycogen or glycogen (during Skin Frog, earthworm and leeches
deficiency of glucose) is converted into Gills Fishes, tadpoles and prawns
glucose. Trachea Insects, centipedes and
• It destroys dead RBC and regulates body millipedes.
temperature. It converts excess of amino Body surface Armoeba, Euglena,
acid into ammonia (which is converted Chlarmydomonas, Spirogyra,
into urea by Ornithine cycle). Urea Hydra, etc.
comes out from the body through kidney. Book lungs Spider, scorpion, ticks and
• If there is any obstruction in bile duct, miles.
liver cells stop taking bilirubin from the Book gills King crab, prawn, cray fish
blood, consequently it spreads and Daphnia.
throughout the body which is called Air
jaundice. bladder Lung fish and bony
fishes(e.g., Labeo).
• Liver is an important body organ in
Air sacs/lungs Birds
investigation of a person's death that has
been due to poison in food.
GENERAL KNOWLEDGE ~ General Science 429

Human Respiratory System Glucose.

yeast
Carbon dioxide+
• Overall passage of air in humans is as ethyl alcohol
follows:
muscles +Energy (in plants)
Nostrils Pharynx Larynx Trachea Glucose Lactic acid
Bronchi Bronchioles Alveoli + Energy (in animals)
Cells Blood.
• The human respiratory system is shown
in the following diagram.
PHASES OF AEROBIC
-Epiglotis RESPIRATION
-Larynx
External Respiration

e
-Trachea
(Breathing or Ventilation of

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Bronchus Lungs)
Pleural • It involves inspiration and expiration of
Cut end -membranes
of rib air.
-Alveoli
Lung -Pleural fluid Inspiration is the process of intake of air.
Diaphragm
Bronchiole
ra During inspiration, muscles of the
diaphragm contract and diaphragm
Human Respiratory System flattens.
.
The lower ribs are raised upward and
outwards. The chest cavity enlarges, the
nt

Types of Respiration air pressure in the lungs gets decreased

Aerobic Respiration and air rushes into the lungs.
•
The respiration taking place in the •
Expiration is breathing out of air. During
presence of oxygen is known as aerobic expiration, relaxation of muscles of the
ie

respiration. ribs and diaphragm takes place.

• This respiratory oxygen oxidises the Diaphragm again become dome-shaped.
substance into carbon dioxide, water Chest cavity is reduced and air is
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and energy, as follows forced outwards through nose and

Glucose +O, Carbon dioxide trachea.
+ Water + Energy. • Breathing rate in
humans is 18 - 20 times
In this process, each glucose molecule is per min.
converted into two molecules of pyruvic• The exchange of gases, i.e., oxygen and
@

acid by the process, called glycolysis. It carbon dioxide takes place due to the
takes place in the cytoplasm of the cell. difference in their partial pressures.
The pyruvic acid formed, releases energy
with the formation of carbon dioxide and Internal Respiration
water (in Kreb's cycle which occur in (Oxidation
of Food)
mitochondria). • It is a complex process in which food is
Anaerobic Respiration broken down to release energy.
•
The respiration taking place in the Iransporation of oxygen takes place by
absence of OXVgen is known as haemoglobin of blood. Whereas
anaerobic respiration. transportation of only 10-20% carbon
• It is found dioxide takes place by haemoglobin of
in endoparasites like blood.
roundworm. In this process, the
respiratory substances are incompletely APproximately 400 ml water is lost
oxidised to carbon dioxide and alcohol. through breathing everyday.
430) GENERAL KNOWLEDGE~General Science

Respiration being a catalytic process, also fluid, which allows frictionless

reduces the weight of the body. movements of heart and protects it from
Larynx or voice box or Adam's apple
mechanical shocks.
produces sound. It has a small flap of
cartilage called the epiglottis, which
AortaFm Blood lo
the body
prevents the food from entering the trachea. Blood from Blood lo the
- the body lungs
Purring sound in cats is due to the
Blood from
vibration of false vocal cord.
the lungs
In hippopotamus, true vocal cord is absent.
Left
Total Lung Capacity (TLC) = 6000 mL Right auricle
Residual Volume (AV) = 1200 mL

e
auricle
Tidal Volume (TV)=500-600 ml

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Lelt
Right ventriole
CIRCULATORY ventricle

SYSTEM Human Heart

• It is a transport system that supplies the •
ra Fishes have only two-chambered heart
useful material and removes the waste (one auricle and one ventricle).
from the body cells.
consists of heart, blood vessels and amphibians, heart is
blood. three-chambered.
• In crocodile, birds and mammals, the
nt

HEART heart is divided into four chambers (two

auricles and two ventricles).
• Heart is a thick, muscular, contractile,
automatic pumping organ of blood Reptilian heart is structurally three
chambered but is functionally four
ie

vascular system.
• chambered (ie., incomplete four
The chamber which receives the blood
chambered) except in crocodile.
from body tissues are called auricles and A new born baby's heart weight is about
the chambers of heart which pump blood
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to body tissues are called ventricles. 20 g.

•
There is a thin two layered sac around The average weight of heart in men
the heart known as pericardium, filled is 280-340 g, while in Women is
with a watery fluid called pericardial 230-280g.
@

Diseases of Heart
Angina pectoris Pain in heart muscles, appearing as chest pain. It is caused due to
obstruction in coronary artery.
Tachycardia Increased rate of heartbeat.
Bradycardia Decreased rate of heartbeat.
Heart attack Breathlessness, palpitations, pain in the chest, unconsciousness
appear suddenly (Nitroglycerine is used for the treatment).
Heart block When heart beat is not passed to the ventricles properly. This is the
defect of conducting system of the heart.
Coronary thrombosis Due to the formation of clot in coronary artery.
Myocardial infarction It is the death of a part of heart muscle following cessation of blood
supply to it. It is acute heart attack.
GENERAL KNOWLEDGE ~ General Science 431

• The circulation of blood through the whole This extra blood supplies additional
body can be shown as Oxygen to body cells.
Superior Vena cBva • During blood clotting fibrinogen
Right Alight ventriole changes into fibrin by thrombin
|atrium
Inlerior Vena cava which is obtained from thrombop
Pulmonary arlery lastin in the presence of Ca+
De-oxygenaled blood The haemoglobin content of adult
Oxygenated blood
Lungs female varies from 13.5-14.5%
Capillaries in Capillaries in Pulmonary veins
whereas in adult male its amount
head region body organs varies from 14.5-15.5% Haemoglobin
count is highest in the foetus and is

e
-Aorta Left ventricle Lett alrium about 23 g per 100 mL of blood at
Circulation of Blood through the Whole Body birth.

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• To pump out blood, the heart chamber Blood Vessels
undergoes alternate contraction called Blood vessels are of three types
systole and relaxation called diastole. The
regular sequence of these systole and Arteries
ra
diastole causes the heart sound Lub and . These are thick walled blood vessels
Dub. which carry the blood away from the
• Arteries carry pure blood from
the heart heart to various body parts. These are
while veins carry impure blood to the heart. deep seated in the body and have no
nt

• Human
heart beat is myogenic in nature, valves in them.
a
i.e., initiated by patch of modified heart • These carry oxygenated blood except
muscles itself without requiring an external the pulmonary artery which carries
stimulation. This patch is called SA node deoxygenated blood to the lungs. In
ie

(sino-auricular node) or pacemaker. arteries, blood flows at a high

•
When SA-node becomes defective, i.e., it pressure and a higher speed.
does not generate cardiac impulses, it can
be cured by surgical grafting of an artificial Veins
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pacemaker (an electric device) in the chest• These are thin walled blood vessels
of the patient. It stimulate the heart and carry blood away from various
electrically at regular intervals. body parts towards the heart. These
• The normal rate of heartbeat at rest is have valves in them to prevent
@

about 70-72 times per minute. In a newly back flow of blood in them. Blood
born baby, heartbeat rate is about 140 per flows at low pressure and at a lower
minute. speed.
• During
heavy exercise it may be high as These carly deoxygenated blood
170-200 times per minute. except the pulmonary vein which
carries Oxygenated blood to the heart.
BLOOD Capillaries
• Blood is a fluid connective tissue and
composed of blood corpuscles, plasma and These are the thinnest blood vessels
platelets. and connect arteries to the veins.
•
• It is slightly alkaline is nature (pH 7.4). These help in exchange of materials
like the nutrients, gases, waste
• Its volume in an adult is 5.8 L. products etc., between blood and
• The oxygenated or pure blood is bright red cells.
while the deoxygenated blood is purple
coloured (Darker shade of red).
• People who live at high altitudes have more
blood than those who live in low regions.
 432) GENERAL KNOWLEDGE~ General Science

Blood Type of Parent and their Children • Mature red blood cells lack a
nucleus and organelles in
Blood Type of Parert Possible Blood Type of mammals. However, in camel
(Homo or Heterozygous) Children and llama it is nucleated.
.
Ox0 One RBC contains about 280
OxA O, A haemoglobin molecules.
OxB 0, B

Ox AB A, B Leukocytes (WBCs)
AxA A, O These are part of the body's
AxB 0, A, B, AB immune system; they destroy and
remove old or aberrant cells and
A, B, AB

e
Ax AB
cellular debris, as well as attack
BxB B, O
infectious agents and foreign
Bx AB A, B, AB substances. These are much

nc
less
AB x AB A, B, AB in number than RBCs (1 : 600).

Blood Cells Thrombocytes

Erythrocytes (RBCs) (Platelets)
ra
It is responsible for blood clotting
• Red blood cells contain the blood's haem0globin
and distribute oxygen. (coagulation). It changes
fibrinogen into fbrin.
• RBCs are the most abundant cells.
nt

Comparison between Plasma and Lymph

Plasma Lymph
Itcontains 92% waler, 8% blood plasma Lymph contains a variety of substances
ie

proteins and trace amounts of other malerials

r

including proteins, salts, glucose, fats, water

and WBCs.
It is cellfree part of blood, contain salts, It is modified tissue iluid, contains oells like
Considerable aOunt of proteins as well as
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lymphocyte and monocytes, salt and small

more or less all constiluents of body. amount of proteins. It is colourless.
It flows within blood vessels. It flows within lyrmphatic
vessels.
It takes part in nutrition, exCretion, respiration, It supplies nutrition to tissue devoid of blood
etc., by transporting various materials and helps supply, takes part in fat absorption and
@

in the defence mechanism of the body by defence mechanism of the body.

producing antibodies.
It can coagulate because it contains fibrinogen li can coagulate but very slowly
because it
and prothrombin. contains these tWO in small quantities.

Blood Pressure (BP) If a person has persistent high

•
. pressure then it is called
The pressure created by the blood on the walls of blood
the blood vessels due to the repeated pumping of hypertension and persistent
heart is called blood pressure. It is measured by high blood pressure is 150/90
mm Hg. Factors responsible are
sphygmomanometer.
over eating, fear, worry, anxiety,
• It can be felt at certain places in our body viz,
sorrow etc. Hypotension is
wrist of the hands etc.
condition of low blood pressure,
• Blood pressure is recorded as systolic/diastolic.
i.e., persistent 100/50 mm Hg.
Blood pressure in a normal person is 120/ 80 .
mmHg. Factors affecting blood pressure are age, Electrocardiograph (ECG) is
used to check proper working of
cardiac output, total peripheral resistance etc.
heart by using electrodes.
GENERAL KNOWLEDGE~General Science 433

Hips (Pelvic girdle)

SKELETAL SYSTEM Ilium, ischium,
Pubis
2

The human skeleton consists of both fused (Innominale)

and individual bones supported and Thigh Fermur
supplemented by ligaments, tendons, Knee Patella 2
muscles and cartilage. Tibia-Fibula
Shank 4
It is divided into two parts Ankle Tarsal 14
Sole Metatarsal 10
Axial Skeleton (80 Bones)
• Toes Phalanges O8
It includes skull, vertebral column and
bones of chest (ribs and sterrnum).
Vertebral column is responsible for the Joints

e
.
upright position of the human body. The structural arrangements of tissues by
Which bone and bone or bone and cartilage

nc
• Most of the body weight is located at the
joined together.
back of the vertebral column. It provides
flexibility to the neck and protection to They are of following types
spinal cord. Joint Nane Location
Immovable
ra Bones of skull
Appendicular Slightly movable Pubic bones of pelvic
Skeleton (126 Bones) girdle
Hinge Ankle, Knee, elbow
Their function is to malke locomotion
possible and to protect the major organs of Ball and Socket Shoulder and hip
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locomotion, digestion, excretion and Pivot Radius and humerus

reproduction.
Saddle Metacarpal and carpal
Important Bones in the Body Gliding Vertebra, radio-ulna and
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carpals
Body Part Name of the Total
Bones Number •
Skull (29) Facial
Tendons join the muscles and bones.
14 •
The muscles which join bone to bone are
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Cranium 3
called ligaments.
1
Hyoid
Ear ossicles 6 Diseases of Skeletal System
(maleus, • Hard tissue deposits over articular
@

Incus,slapes) cartilage along with higher secretion of

Vertebral Cervical 7 synovial fluid causing pain and stiffness
column(26)
lead to rheumatoid arthritis. (An auto
(Note-The total Thoracic 12 immune disease).
number of bones in Lumbar • Tearing of
vertebral column,
5 articular cartilage and
initially is 33 and Sacrum 1(5) development of bony lumps at places
after development, Cocoyx 1(4) causing pain, stiffness and permanent
it
reduces to 26) bending lead to osteoarthritis.
Bones of chest (25) Sternurm .
Osteoporosis is loss of bone density due
Ribs 24 to excessive absorption of calcium and
(12 pairs)
phosphorus from the bone.
Shoulder (Pectoral Scapula 4 • Osteopetrosis is a hereditary disease
girdle) Clavicle
marked by abnormally dense bone and by
Upper arm Humerus 2 the common occurrence of fractures of
Fore arm Radius-ulna 4 affected bone.
Wrist • Birds have spongy bones with air filled
Carpals 16
Palm Metacarpals 10 spaces, called pneumatie bones.
Fingers Phalanges 28 Rigor mortis is the state of body
stiffening after death.
 434 GENERAL KNOWLEDGE~General Science

.
Chronic fatigue is the inability of a Ureotelic Animals
muscle to contract due to depletion urea,
of its chemicals and lactic acid Ihey excrete nitrogen in the form of
e.g., mammal (man), frogs, toads, other
accumulation by repeated contraction. amphibians
A completely fatigued muscle refuses to and cartilaginous fishes like
sharks.
respond to nervous stimuli.
Uricotelic Animals
Muscular System They exCrete the nitrogenous wastes in the
• Human body has about 639 types of form of uric acid, e.g., Reptiles, snakes,
muscles. lizards, crocodiles and birds.
• Muscles specialised to contraction are
Human Excretory System

e
of three types, i.e., striated, unstriated
and cardiac. The human excretory system includes-the

nc
• kidneys (two), ureters (wo), urinary bladder
Striated muscles Also called skeletal
muscles or voluntary muscles. Thev are (one) and urethra (one).
present in limbs, tongue, pharynx etc. Kidney
• . It
Unstriated muscles These are is bean-shaped, chocolate brown organ
involuntary muscles and present in
ralying in the abdomen, one on each side
urinary bladder, in walls of large blood
vessels and alimentary canal. the vertebral column just below the
. diaphragm.
Cardiac muscles They are involuntary, The left kidney is placed a little higher
striated and non-fatigued fibres which than the right kidney (but reverse in
nt

are found in the wall of heart, where rabbit).

they form myocardium. They generate .
These form the urine and controls
their oVn wave of excitation. osmotic pressure within the organism with
respect to external environment.
ie

EXCRETORY SYSTEM .
Nephrons are the functional and
The process of removal of nitrogenous structural unit of kidney. Each nephron is
wastes from the body is called excretion. made up of BowIman's capsule and renal
jm

The organs of excretion are called tubule. Renal tubule is made up of

excretory orgas. Proximal Convolutid Tubule (PCT),
Henle's loop, Distal Convoluted Tubule
Excretory Organs (DCT) and Collecting Tubule (CT).
of Some Animals
@

Excretory Organ Animal

Ureters
Contractile vacuole Armoeba
These bring the urine downward and open
into urinary bladder.
Flame cells/solenocytes Tapeworm
Renette cell Ascaris Urinary Bladder
Earthworm • It temporarily stores the urine.
Nephridia
Malpighian tubules Cockroach •
Itcan hold about 0.5-1.0 L of urine.
Coxal glarnds Scorpion It is absent in birds. In both reptiles and
Green glands Prawn birds, ureters and rectum, opens into a
Common sac called cloaca.
Excretory Products Urethra
Ammonotelic Animals • It is a muscular and tubular structure
These animal excrete nitrogen in the which extends from neck of bladder to
form of ammonia, e.g., aquatic outside. In females, this tube is small and
serves as a passage of urine only.
invertebrates Amoeba, Hydra, Prawn,
Pila, and freshwater fishes, bony fishes, In males, it is long and functions as a
Frog's tadpole. common passage for urine and spermatic
fluids.
GENERAL KNOWLEDGE~ General Science 135)

Urine The functions of brain parts are as

follows
• It is a pale yellow coloured fluid due to
presence of urochrome pigment. Forebrain
• It is acidic nature
in (pH 6.0) and is slightly Cerebrum leads to consciousness,
heavier than water. storage of Imemoly having
• It has a faint aromatic odour due to urinoid. information.
Daily urine output in normal adult is Thalamus deals with touch, visual
1.5-1.8 L. system, sleep and wakefulness.
.
Chemical composition of urine : water is . Hypothalamus deals with water
95-96%, urea is 2% and some other substance balance in body, behavioral patterns
like uric acid, creatinine, etc., are 2-3%.

e
of sex, sleep, stress emotions etc. It
• The
urine on a
standing gives pungent smell. also regulates pituitary hormones
It is due to conversion of urea into ammonia metabolism

nc
and of fat,
by bacteria. carbohydrate water and maintain
Haemodialysis is the process of removal of body temperature (homeostasis).
excesss urea from the blood of patient using
artificial kidney. Midbrain
ra auditory
•
Kidney stone are generally calcium oxalate It deals with visual analysis,
crystals. etc.
Broca's area is present in brain and is
NERVOUS SYSTEM related with speech production, while
nt

• The nervous system provides the fastest Wernick's area of brain is related
means of communication within the body so with understanding of speech.
that suitable response to stimuli can be made
at once. Hindbrain
ie

• Nervous system is found only in animals and . Cerebellum controls coordination

absent in plants. of accurate movements and
• In most animals, the nervous system consists balancing.
jm

of two parts-central and peripheral nervous. Medulla oblongata is long

system. part to
connecting of brain spinal
cord. It deals with control of heart
Central Nervous beats, blood vessels, breathing,
System (CNS)
@

salivary secretion and mostly reflex

and involuntary (uncontrolled)
Brain Imovements.
• Brain lies in the cranium of skull.
• Cerebrospinal fluid is present in brain and
spinal cord. Nobel Prize in Medicine 2016
The Nobel Prize in physiology or
Brain medicine 2016 was awarded to
Yoshinori Ohsumi "for his discoveries of
mechanisms for autophagy.
The word 'autophagy' originates from
Forebrain Midbrain Hindbrain
the Greek words auto, meaning 'self and
-Cerebrum Optic lobes -Cerebellum phageil meaning to 'eat'. It is an
(Largest part Tectum -Medulla evolutionarily conserved process in
of brain) oblongata which the eukaryotic cell can recycle
Thalamus Cerebral
(Hypothalamus) Pons varolii part of its own content.
peduncle
-Olfactory Lobes
 436) GENERAL KNOWLEDGE~ General Science

Spinal Cord Electroencephalogram (EEG) is a test

that measures and records the electrical
Deals with impulses to and from the brain activity of our brain.
and is the centre for reflex actions like
blinking of the eye when an object comes
near to eyes suddenly, rapid SENSEORGANS
withdrawal of hand while coming near to Eye
heat, knee jerk reflex etc. are the sensitive detectors of light. The
Acquired reflex action is also called Eyes eye can distinguish about 10 million
human
conditioned reflex as dependent on past colours.
experience, training and learning.
lt consists of three parts
It was first demonstrated by Ivan Petrovich
Sclerotic Layer

e
Pavlov e.g. learning, dancing, cycling,
which
swimming, singing and driving etc are It is the outermost, bony layer,

nc
controlled by spinal chord. It is under ncludes
cerebral control during learning. Cornea the clear, dome-shaped tissue,
covering the front of the eye.
Peripheral Nervous Conjunctiva, the continuation of upper
eyelid.
System (PNS)
ra
• It is a collective term for the nervous Choroid Layer
system structures that do not lie within
the CNS. It is the middle layer and consists of
• It is composed of cranial and spinal 1. Pupil is the black hole in the centre
nt

nerves. There are 10 pairs of cranial of the iris. It changes size as the
nerves in fishes and amphibians and amount of light changes.
12 pairs in rest of the higher chordates. 2. Ciliary muscles regulates the lens
• There are 10 pairs of spinal nerves Curvature.
ie

found in fishes and amphibians and 3. Iris is the coloured part of the eye. It
31 pairs in humans. controls the amount of light that enters
• The PNS is divided into two divisions: the eye by changing the size of the
jm

Somatic Nervous System (SNS) and pupil.

Autonomous Nervous System (ANS). 4. Lens is biconvex transparent
• It is a part of peripheral nervous system circular solid located just behind the
that relays impulses from the CNS to iris. It focuses light onto the retina.
@

skeletal muscles. Retina

Iris Lens
Fovea (point of
Autonomous Nervous central focus)
System (ANS) Optic nerve to
Pupil brain's visual
It is also a part of peripheral nervous Cortex
system that transmits impulses from the Cornea
CNS to involuntary organs and smooth Blind spot
muscles of the body. Autonomic nervous
system consists of two divisions The Eye
1. Sympathetie Nervous System
increases defence system of body Retina
against adverse conditions. It is active Light sensitive tissue that lies at the
in stress condition, e.g., pain, fear and back of the eve. It contains millions of
anger. photoreceptors (rods and cones) that
2. Parasympathetic Nervous System convert light rays into electrical impulses
provides relaxation, comfort, pleasure that are relayed to the brain via the optic
at the time of rest. It helps in the nerve.
restoration and Conservation of The image formed on retina is real and
energy. inverted.
GENERAL KNOWLEDGE ~ General Science 437

•
Rods are highly sensitive to dim light and Correspondence between
contain a reddish purple pigment called Camera
rhodopsin. Night vision involves mostly rods
and Eye
(not cones). Part of Carmera Corresponding
Part of Eye
• Cones are sensitive to bright light, hence
differentiate the colours. Box Sclera
• The fovea centralis the area of sharpest Black inner paint Choroid
vision due high concentration of cones.
to Shutter Eye lids
• The blind spot (optic disc) has no rods and Diaphragm Iris
cone cells, hence no image is form in this
Light hold Pupil
region.

e
Lens Lens
Eye Defects Light sensitive film Retina

nc
plate
Nearsightedness (Myopia)
. A condition in which nearby objects are seen
more clearly than distant objects because
Ear
light is focused in front of the retina, not on it. Ears are meant for both balancing
and hearing.
ra
It carn be corrected by using concave glasses.
• It can be divided into three parts
Farsightedness (Hypermetropia) as External ear (pinna +
• A condition in vhich distant objects are seen external auditory canal), Middle
more clearly than nearby objects because light ear (tympanic cavity) and Internal
nt

is focused behind the retina, not on it. ear (bony and membranous
• It can be corrected by using convex glasses. labyrinth).
• Hearing is controlled by auditory
Astigmatism area of temporal lobe of cerebral
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• A condition in which the lens is warped, COrtex.

causing images not to focus properly on the Human ear can receive the sound
retina. ranging between 60-80 decibel.
jm

• The cylindrical glass can correct the defect. Human ear is sensitive to sounds
• Colour blindness also called Daltonism is frequency 50-20,000 cycles/sec.
caused due to deficiency of cones. While Defects of ear are : Otalgia ear,
night blindness is due to deficiency of ache (Pain in ear); Othitis media
@

rhodopsin in rods. (Acute infection of middle ear)

•
Retina of Owl contains only rods while fowl Labyrithine disease (malfunction
contains only cones. of inner ear).
• The eyes of
carnivores like cat, dog, iron sea
etc, glow in night due to tapetum lucidum. Nose
Eyes are most sensitive to yellow green. Nose is a sense organ for smell or
colour. Bees can see ultraviolet light. olfaction. It contains
Presbyopia 1. Olfactory cells which are more
• It is a reduction
chemosensitive than taste cells.
in pupil size and the loss of 2. Olfactory stimuli such as,
accommodation or focusing capability with
age, leading to substantial decrease in light
a chloroform and ammonia are
received at the retina. irritating and can cause tearing.
• Dogs have an acute olfactory sense.
• Bifocal lens can correct the defect.
•
Conjunctivitis is inflammation of They can trace people because they
can distinguish between the odours
conjunctiva by bacteria. of different persons.
 438) GENERAL KNOWLEDGE~ General Science

Males can produce spermatozoa

REPRODUCTIVE (sperm) throughout their life from age
SYSTEM of 13-14 years. The growth of hairs on
• The pro cess by which new individuals are body is due to masculine hormones.
produced from their parents is called
reproduction and the organs which are
Used for this process, collectively Urinary
constitute the reproductive system. bladder Seminal
• Reproduction is of two types, i.e., asexual vesicle
(behind
and sexual. bladder)
•
In asexual reproduction, only one parent Proslale

e
gland
is involved and sex cells are not involved. Bulbourelhral -Urelhra
• In
sexual reproduction, two parents are gland

nc
-Sorolum
involved and formation and fusion of Ereclile tissue
gametes takes place. of penis
Vas delerens Glans
Modes of Reproduction in penis
Different Organisms Epididymis
ra Teslis
Mode of Orgarisrn Male Reproductive System
Reproduction
Fission (asexual) Amoeba, bacteria,
flatworm etc.
Female Reproductive
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Budding (asexual) Hydra, yeast and sponge

etc. System
Syngarny (sexual) Cockroach, frog and Female reproductive system includes
human being etc. following organs which are tabulated
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below
Male Reproductive System Reproductive No Function Performed
• The various organs which constitute the Organ
male reproductive system and their
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Ovaries 2 To produce ova and

functions are tabulated below: hormones.
Reproduotive No Function Oviducts 2 To move the ovum
Organ towards uterus.
Uterus 1 To provide space for
Testes 2 Produce sperm and
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developing child.
testosterone
Vagina 1 To receive the
Sperm duct 2 Conduct the sperm
from the testes to sperms.
urethra Oviduçt
Serninal vesicles Ovaries
2 Secrete seminal Follicles
plasma
Epididyrmis Temporarily store
sperm and provides
mobility.
Urethra Conduct urine and
sperms. Uterine Corpus
Ulerus Vwall
Prostale gland 2 Secrete an alkaline luteum
tluid to neutralise the Cervix Endomelrium
acidity of urethra and
make the sperM
more active. Vagina

Cowper's gland 2 Secrete an alkaline

white lubricating tluid. Female Reproductive System
Penis (have rich 2 Pass urine and
blood supply) deposit sperm in If sperm is present, the egg will be
female genital tract. fertilised in the ampullary isthmic
junction of Fallopian tube.
GENERAL KNOWLEDGE ~ General Science 439)

• After maturity the ovary releases an • Amniocentesis or amniotic fluid test is

oVum (egg cell) after every 28 days. technique of finding out sex and disorder
• The connection between developing of foetUs.
embryo and mother is made by
placenta. It supplies blood, organic and Gestation Periods of Some
inorganic nutrients, hormones. Animals
antibodies etc. Animal Gestation Animal Gestation
• The embryo develops for nine months in Period Period
uterus. It is called gestation period. 310 days Horse
•
Buffalo 340 days
Child is delivered after its development 610 days
Elephant Leopard 105 days
and mother produces milk to nourish 120 days 103 days
Lion Tiger

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the child (lactation).
Whale 365 days Squirrel 40 days
• The first milk which comes out from the
mother's mammary gland just after

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•
child birth is called colostrum.
This milk is rich in protein, antibodies
ENDOCRINE SYSTEM
It includes endocrine or ductless glands.
which imparts imnmunity to new born
baby. Their secretion is known as hormones.
Different types of hormones are
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Menstrual Cycle Steroids, e.g., oestradiol, testosterone,
• Reproductive period of a human female androsterone, aldosterone, cortisol and
extends from puberty (10-14 years) to cortisone.
menopause (40-50 years). Peptides, e.g., insulin, glucagon,
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• The release of the first menstrual flow or pituitary hormones, parathormone and
period is called menarche. relaxin.
• of Amino acid derivatives, e.g., adrenaline,
Menarche marks the Onset
reproductive life and onset of puberty in noradrenaline and thyroid hormones.
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females. Various glands are:

• Menopause is stopping of ovulation and
menses. It normally occurs between the Hypothalamus
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age of 45 to 55. This stage onwards, It is a part of forebrain and regulates the
woman lose the ability to reproduce. pituitary glands and maintains body
(homeostasis).
•
The periodic vaginal bleeding during temperature
menstrual cycle is called menstruation.
pituitary Gland or
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• On an average menstural cycle is

completed in 28 days. Hypophysis
• It is absent during pregnancy, may be It governs other endocrine glands like
Suppressed during lactation and thyroid, adrenal and gonads.
permanently stops at menopause. About• Pituitary gland is also known as master
13 mature eggs are released from two gland.
ovaries of female in a year.
•Menstrual cycle is controlled by FSH, Thyroid Gland
LH, oestrogen and progesterone• It is the largest endocrine gland and
hormones. located in neck region.
It is the 'pace setter of the endocrine
Birth Control Methods or system. It secretes
Contraception Methods 1. Thyroxine, which regulates BMR
• The prevention of union of spermn and (Basal Metabolic Rate), physical,
oVum is known as contraception. The mental and sexual development.
various methods used for it ale 2. Thyrocalcitonin secreted by the
diaphragm, contraceptive pills, C-cells and regulates the calcium
tubectomy, vesectomy, copper-T etc. homeostasis (lowers calcium level).
440 GENERAL KNOWLEDGE~ General Science

Pancreas HEALTH
It is both an exocrine and endocrine gland. Healrh is
the functional or metabolic
The islet of Langerhans (endocrine) have
three major types of cells efficiency of a living being. In human, it is
a
1. Alpha-Cells secretes glucagon hormone the general condition of person's mind,
body and spirit. usual meaning, to be free
which increases blood sugar level. from illness, injury or pain.
2. Beta-Cells secretes insulin, which
decreases the amount of sugar in the DISEASES
blood.
3. Delta-Cells secretes Somatostatin It is a condition of the body or its part in
which is an anti-growth factor. which functions are disturbed. The

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diseases may be broadly classified into
Adrenal Gland two types, i.e., congenital and acquired.

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• It is also known as emergeney gland.
(a) Cortex (outer layer)
Congenital Diseases
(b) Medulla (inner layer) It secretes twoThese are anatomical or physiological
orabnormalities present from birth.
important hormones-- Epinephrine or
They may be caused by
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adrenaline and nor-epinephrine
• A single gene mutation (alkaptonuria,
noradrenaline
• It increases the blood glucose level, blood phenylketonuria, albinism, sickle-cell
pressure and cardiac output. anaemia, haemophilia and colour
blindness).
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Pineal Gland • Chromosomal aberrations (Down's

• It is situated in
the brain and also knoWn syndrome, Klinefelter's syndrome and
as clockvwork gland. Turner's syndrome).
the ovaries and has an effect Environmental factors (cleft palate
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• It regulates
on the biological rhythm. and harelip). Unlike the gene and
chromosome induced congenital
defects, environmentally caused
GONADS
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abnornalities are not transmitted to the

These secrete steroid hormones. children.

Ovarian Hormones Acquired Diseases

(Oestrogens)
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These diseases develop after birth.

It helps in the development of primarv and Ihey are further of tvo types, i...
secondary sexual characters (oestradiol. Communicable and non-communicable.
1. Communicable (infectious)
oestriol and estrogen). Hypersecretion of
androgenic steroids in female results in diseases are caused by pathogenic
stopping of menstruation, hairs on face and micro-organisms, such as bacteria,
breasts. viruses, parasites or fungi; the
diseases can be spread, directly or
Testicular Hormones indirectly from one person to
another. Infectious diseases, are also
(Androgens) known as transmissible diseases.
These are produced by Leydig cells of 2. Non-communicable (non
testes.It stimulate growth, maturation and infectious) diseases are not passed
maintenance of male gonads and by organisms among people, but
development of secondary sexual characters, come from genetic or lifestyle
e.g., testosterone, androsterone etc.
factors.
GENERAL KNOWLEDGE~General Science 441

COMMUNICABLE Treatment
Antibiotics to treat bacteria that
DISEASES cause pneumonia. Antiviral medications.
These are the diseases which may pass or High doses of steroids to reduce swelling in
carried from one human or animal to the lungs. Oxygen, breathing support
other. (mechanical ventilation) or chest therapy.
Communicable diseases are illness caused
by germs such as bacteria, viruses and Hepatitis
spread by an infected person, animals or Hepatitis is a swelling and inflammation of
object to other persons. the liver. It is not a condition, but is often
used to refer a viral infection of the liver.
Viral Diseases

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Hepatitis can be caused by
Viruses are parasitic and causes a number . Immune cells in the body attacking the

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of diseases. liver and causing autoimmune hepatitis.
Bird Flu (H,N) Infections from viruses (such as
hepatitis-A, B or C), bacteria or
Bird flu (Avian influenza) is a disease parasites. Liver damage from alcohol,
caused by an influenza virus-A, that poisonous mushrooms or other poisons.
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primarily affect birds. • Medications, such as an overdose of
The following persons may be on higher risk acetaminophen, can cause harm or death
for developing the bird flu also.
• Farmers and others, who work with
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poultry. Symptoms
• Travellers, visiting affected countries. Abdomimal pain or distention. Breasts
• Those who have touched an infected development in males. Dark
urine and
bird. pale or clay coloured stools. Fatigue,
. Those who eat raw or undercooked general itching, fever, usually low-grade
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poultry meat, eggs from infected birds. jaundice (yellowing of the skin or eyes)
and loss of appetite, nausea, vomiting and
Symptoms weight loss.
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Fever, cough, sore throat, muscle aches and

eye infection (conjunctivitis). AIDS
Acquired Immuno Deffciency Syndrome
Treatment (AIDS) is a disease of the human immune
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Treatment with the antiviral medication system caused by the Human

Oseltamivir (tamiflu) or zanamivir (relenza) Immunodeficiency Virus (HIV). AIDS was
may make the disease less severe. first recognised by the Centres for Disease
Oseltamivir may also be prescribed for Control and Prevention (CDC) in 1981.
persons, who live in the same house as
those diagnosed with avian flu. HIV Infection
AIDS is a condition caused by HIV
Severe Acute Respiratory infection. The condition gradually
Syndrome (SARS) destroys the immune system, which
makes it harder for the body to fight
It is a serious form of pneumonia. It is infections.
caused by a virus that was first identified in
2003. Infection with the SARS virus causes Transmission
acute respiratory distress (severe
Dreatmš HIV Can be spread by the following
difficulty) and sometimes death.
• Through sexual contact i.e. oral, vaginal
Symptoms and anal sex.
Cough usually starts 2-3 days after other Through blood transfusions, accidental
symptoms like Fever, headache and muscle needle sticks or needle sharing.
aches.
 442) GENERAL KNOWLEDGE~General Science

• From mother to child: A pregnant woman Causes of Cancer

can transmit virus to her foetus through
their shared blood circulation or a nursing Cancer is induced by physical,
chemical and biological factors or
mother can pass it to her baby through agents. These are called carcinogens
breast's milk. or cancer causing agents. lonising
Test forAIDS radiations such as X-rays, y-rays and
• Enzyme non-ionising radiations such as
Linked Immunosorbent Assay/ ultraviolet (UV) damage the DNA
Enzyme Immuno Assay (ELISA/EIA)
leading to neoplastic transformation.
• Radio Immuno
Precipitation Assay/ Indirect , Tobacco smoke contains chemical
Fluorescent Antibody Assay (RIP/IFA) carcinogens that causes lung cancer.

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• Polymerase Chain Reaction (PCR)
Viruses also cause cancer. These are
• Western Blot Confirmatory Test.
called oncogenic viruses as they have

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genes called viral oncogenes.
NON-COMMUNICABLE Cancer Detection
DISEASES and Diagnosis
There are various kinds of or blood cancer can be
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non-communicable diseases. which affert Leukaemiadetected based On biopsy and
the health of human beings. Some of the histopathological studies of the
common non- communicable diseases are tissue
and blood and bone marrow tests for
increased cell counts. Cancers of
Diabetes
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internal organs are detected using

Diabetes is a long-term condition caused by too techniques such as Radiography
much glucose (sugar) in the blood. There are Computed Tomography (RCT) and
two main types of diabetes Magnetic Resonance Imaging (MRI).
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Type 1 Cancer Therapy

Diabetes occurs when the body doesn't •
Cryo Surgery It is the technique of
produce enough insulin to function properly or
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using extreme rapid cooling that freeze

the body's cells don't react to insulin. This is tissues, thereby destroy them. Rapid
known as insulin resistance. cooling to temperature below freezing
point produces irreversible cell damage
Type 2 -
and cell death occurs at 20°C to 90°C.
Diabetes is far more common than type 1
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Proton Therapy Itis a type of particle

diabetes, which occurs when the body doesn't therapy, which uses a beam of protons to
produce any insulin at all. iradiate iseased tissue, most often in
the treatment of cancer.
Symptoms
Radiation Therapy Radiation therapy
Symptoms common to both types of diabetes is a cancer treatment. Its goal is to kill
include cancer cells and shrink tumours.
) Feeling very thirsty. Stem CelI Transplantation Stem cell
(ii) Urinating frequently. particularly at night. transplants can be an effective treatment
(ii) Feeling very tired. for people with certain forms of cancer,
(iv) Weight loss and loss of muscle bulk. Such as leukaemia and lymphoma.
Peripheral Blood Stem Cell
Cancer Transplantation (PBSCT) It is also
It is uncontrolled growth of abnormal cells in called peripheral stem cell support. This
the body. Some diseases cause emergence of procedure restore stem cells that has
tumours in body. These are called neoplastic been destroyed by high doses of
diseases. This includes from a minor role to a chemotherapy.
lethal cancer.
GENERAL KNOWLEDGE ~ General Science 443

Heart Diseases Osteoarthritis

Some heart diseases are as follow It is a joint inflammation that results
from cartilage degeneration. It can be
Angina Pectoris caused by ageing, heredity and injury
Human with angina, experience pain in the from trauma or disease. The most
centre of the chest. The chest can feel common symptom of osteoarthritis is
constricted and tight, but the pain can also be pain in the affected joint(s) after
oppressive, as if something is crushing your repetitive use.
chest. Pain starts in the centre of the chest
behind the breast bone (sternum) or on the left Gout
side of the front of the chest. It can spread out to Gout is a kind of arthritis. It can cause
other parls of your body like your arms and an attack of sudden burning pain,

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stomach. stiffness and swelling in a joint,
LUSually a big toe. These attacks can

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Myocardial Infarction happen over and over unless gout is
• It is commonly known as
heart attack, results treated. Overtime, they can harm
from the interruption of blood supply to a part yourjoints, tendons and other tissues.
of the heart, causing heart cells to die. Gout is most common in men.
•
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This is most commonly due to occlusion Sexually Transmitted Diseases
(blockage) of a coronary artery following the • Gonorrhoea It
rupture of a vulnerable atherosclerotic is caused by
plaque, which is an unstable collection of bacteria Neisseria gonorrhoeae.
Anyone who has any type of sexual
lipids (cholesterol and fatty acids) and white
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contact can catch gonorrhoea. The

blood cells (especially macrophages) in the
wall of an artery. infection can be spread by contact
• The result is ischemia (restriction in blood
with the mouth, vagina, penis or
anus.
supply) and ensuing oxygen, if left untreated
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Syphilis It is sexually
for a sufficient period of time, can cause transmitted infection caused by the
damage or death (infarction) of heart muscle spirochete bacterium Treponema
tissue (myocardium). pallidum sub-species pallidum.
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Heart Arrest The primary route of transmission

• It occurs when is through sexual contact; it may
the heart is unable to provide also be transmitted from mother to
sufficient pump action to distribute blood flow foetus during pregnancy or at birth,
to meet the needs of the body. Heart arrest
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can cause a number of symptoms including . resulting in congenital syphilis.

Genital herpes It is a Sexually
shortness of breath, leg swelling and exercise Transmitted Infection (STI) caused
intolerance. by the Herpes Simplex Virus
• The condition is diagnosed with (HSV).
echocardiography and blood tests. Treatment Trichomoniasis It is a sexually
commonly consists of lifestyle measures such transmitted infection caused by the
as smoking cessation, light exercise including
parasite Trichomonas vaginalis.
breathing protocols, decreased salt intake and
other dietary changes and medications. Mental Disorder
A mental disorder or mental illness is
Arthritis a psychological pattern or anomali,
• It affects the musculoskeletal system, potentially reflected in behaviour, that
specifically the joints. It is the main cause of is generaly associated with distress or
disability among people over 55 years of age in disability and which is not considered
industrialised countries. part of normal developmnent of a
• Rheumatoid Arthritis (RA) It is a long-term person's culture. This may be
disease that leads to inflammation of the associated with particular regions or
functions of the brain or rest of the
joints and surrounding tissues. It can also nervous system, often in a social
affect other organs. context.
444 GENERAL KNOWLEDGE~ General Science

Alzheimer's Disease Antihistamines

It is a progressive mental deterioration These are medicines that can be used to
that can occur in middle or old age, due torelieve severe itching and help in breaking
generalised degeneration of thebrain. Itis histamine cycle. It leads to thickening and
the commonest cause of premature weeping of the skin and generally makes the
senility. eczema worse and more likely to become
infected because scratching breaks the skin.
DRUGS Tranquiliser
A drug is a substance, which when taken
a an
in, alters the body functions. Repeated use It is drug that induces tranquility in a
of drugs particularly for obtaining quick individual. The minor tranquilisers induce

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pleasure is called drug abuse. feeling of calm and relaxation. Depending
on the medication and dosage, this can
Some Simple Drugs range

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from feeling of mild euphoria to states
Below are the types of simple drugs
of drowsiness, confusion and lightedness.
Sedative
Analgesic (Pain Killers)
It is a substance that induces sedation by
These drugs act in various ways on the
ra reducing irritability or excitement. At higher
peripheral and central nervous system; doses it may result in slurred speech,
they include paracetamol staggering gait, poor judgment and slow,
(acetarminophen), the non-steroidal uncertain reflexes.
anti-inflammatory drugs (NSAIDs) such
Doses of sedatives such as benzodiazepines,
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as the salicylates, narcotic drugs such as

morphine, synthetic drugs with narcotic when used as a hypnotic induce sleep, tend
to be higher than amounts used to relieve
properties such as tramadol and various
anxiety, whereas only low doses are needed
others. to provide a peaceful and calming sedative
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Anaesthetic effect.
An anaesthetic is used to temporarily Narcotic
reduce or take away sensation, usually so
can be lt is originally referred medically to any
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that painful procedures or surgery

performed. psychoactive compound with any
sleep-inducing properties.
There are two types of anaesthetics
•
General which make the patient Antipyretics
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. unconscious. (Temperature Reduction)

Local which numb the part of the body These are drugs or
herbs that reduce fever.
that would otherwise feel pain. Antipyretics cause the hypothalamus to over
Antibiotics (Bactericidal) ride an interleukin-induced increase in
temperature. The body then works to lower
These are powerful medicines that fight the temperature, resulting in a reduction of
bacterial infections. When Used properly fever.
antibiotics can save lives. They either kill, Bacteria ofcholera and TB was discovered
bacteria or stop them for reproduing. by Robert Koch.
GENERAL KNOWLEDGE ~ General Science 445)

Disorders Caused by Hormonal Irregularities

Disorders Hormone Quantity Gland
Dwarfism GH Deficiency Pituitary
Gigantism GH Excess Pituitary
Acromegaly GH Excess Pituitary
Simmond's disease GH Deficiency Pituitary
Diabetes insipidus ADH Deficiency Piluitary
Cretinism Thyroxine Deficiency Thyroid
Simple goitre Thyroxine Deficiency Thyroid

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Myxoedema Thyroxine Deficiency Thyroid
Exophthalmic goitre Thyroxine Excess Thyroid

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Tetani Parathyroid Deficiency Parathyroid
Plurmmer's disease Thyroxine Deficiency
Addison's disease Mineralocorticoids (aldosterone) Deficiency Adrenal cortex
and glucocorticoids (cortisol)
Crohn's disease
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Mineralocorticoids Excess Adrenal cortex
Cushing disease Corticosteroid Excess Adrenal cortex

Bacterial Diseases in Human Beings

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Disease Pathogen Affected Organ Symptom

Tuberculosis Mycobacterium Lungs Repeated coughing, high fever.
tuberculosis
Diphtheria Corynebacteriurn Respiratory tract Difficulty in respiration (mainly in
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diphtheriae child of age 2-5 yrs).

Whooping cough or Bacillus pertussis Respiratory Continuous coughing.
pertussis system
Vomiting, acute diarrhoea, mus
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Cholera Vibrio cholerae Intestine

Cular cramps, dehydration etc.
Leprosy or Hansern's Mycobacterium Chronic infection Ulcers, nodules, scaly scabs (the
disease leprae of skin and nenve infected part of the body
becomes senseless).
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Telanus (lock jaw) Clostridium telani Central nervous Painful oontraction of neck and
system jaw muscles followed by
paralysis of thoracic muscles.
Pneurnonia DiplococCUs Lungs Sudden chill, chest pain, cough,
pneumoniae high and fever.
Typhoid Salmonella typhi Intestine High fever, diarrhoea and
headache
Anthrax Bacillus anthracis Skin and intestine
Plague Pasteurella, Blood disease High fever, weakness and
Yersinia pestis haenorrhage which turn black.
) Bubonic plague
(ü) Pneurmonic plaque Lungs Haemorrhage of bronchi, lungs.
(ii) Septicemic Anaermia, fever,, chills leading to
plague death with in two days.
Gonorrhoea (sexual Neisseria Urinary tract Swelling in urinary tract
disease) gonorrhoea
446) GENERAL KNOWLEDGE~ General Science

Viral Diseases in Human Beings

Disease Pathogen Affected Part Symptom
Measles (Aubella Rubella virus Whole body Loss of appetite, reddish eruption on
disease) the body
pox
Chicken Varicella virus Whole body High fever, reddish eruption on body.
Srmall pOx Variola virus Whole body Light fever, eruption of blood on body
Polio or Polio virus Throat, Fever, backbone and intestine wall
poliomyelitis backbone cells are destroyed. It leads to
and nerve paralysis.
Influenza (flu) Influenza virus Whole body Inflammation of upper respiratory tract,
nose throat and eyes.
Rabies RNA virus called Nervous Encephalitis, fear of water, high fever,

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(hydrophobia) rabies virus system headache, spasm of throat and chest
leading to death.

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Hepalitis (Epidermic Hepatitis virus Liver Loss of appetite, nausea, whitish stool
Jaundice) and jaundice.
() Hepatiis-A Hepatitis-A virus Not fatal
(i) Hepatitis-B Hepatitis-B virus Fatal
Dengue fever RNA containing Whole body, High fever, backache, headache,
dengue virus
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particularly retro-orbital pain behind the eye ball.
head, eyes
and joints
AIDS (Acquired HIV (Human White blood Weak immune system.
Immuno Deliciency Immuno cells
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Syndrome) Deficiency Virus)

Herpes Herpes virus Skin Swelling of skin.
Ebola virus disease Ebola Virus Whole body Fatal hermorrhagic fever, liver and
(filovirus) kidney disfunction vomiting, headache.
Whole body Headache, tiredness, sore throat,
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Swine influenza (flu) H,N, flu virus

(muscles) Vomiting, breathing problerns.
COVID 19 Novel Corona Respiratory Fever, dry cough, tiredness, aches and
Virus System pains, nasal congestion, headache,
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conjunctivitis, sore throat, diarrhoea,

loss of taste or smell or a rash on skin
or discoloration of fingers or toes.

Protozoan Diseases, their Vectors and Affected Part

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Disease Pathogen Vector Parts Affected and

(Causative agent) Symptoms
Pyorrhoea Entarnoeba gingivalis None, infection by Bleeding of gums.
lip kissing.
African Trypanosoma Tse-tse fly Blood and nervOus tissue.
trypanosomiasis garmbienes (Glossina palpalis) Man feels sleepy, may cause
death.
Amoebic dysenlery Entarmoeba None, Infection by Colon (intestine). Develop
(Amoebiasis) histolytica contamination. loose motion with blood, pain
in abdomen
Diarrhoea Giardia None, infection by Digestive system causes
contamination loose motions, vomitting.
Kala azar or Leishmania donovani Sand tlies Spleen and liver enlarge and
dumdum fever (Phlebotomus) high fever develops.
Filaria or Wuchereria bancrofti Culex mosquito Swelling of legs, testes and
elephantiasis other body parts.
Malaria Plasmodiurn sp. Female Anopheles Periodical attacks of high
mosquito fever, pain in joints
accompanied by chill, heavy
perspiration and fast pulse.
Fishes like cat ish, Garnbusia and aquatic birds eat mosquito larvae.
Quinone, a product of Cinchona tree, is administered for malaria.
GENERAL KNOWLEDGE ~ General Science 447

Fungal Diseases in Human Beings

Disease Pathogen (fungil Syrmptors
Asthma or aspergillosis Aspergillus furmigatus Obstruction in the functioning of lungs.
Athlete's foot Tinea pedis Skin disease, cracking of feet.
Scabies Acarus scabiei Skin itching and white spot on the skin.
Ringworm Tricophyton Verrucosum Round red spot on skin.
Baldness Tinea capitis Hair fall.

Some Immunological Tests and Diseases

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Test Disease Test Disease
Ames test Carcinogenecity Widal test Typhaid

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Dick test Scarlet fever Wayson stain test Plague
Montoux test Tuberculosis Tourniquet test Dengue fever
Rose-Waaler test Aheumatoid fever ELISA test AIDS
Wassermann test Syphilis
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Some iral Diseases in Animals
Animal Virus Disease
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Cow Variola vera Small pox

Buffalo Pox virido orthopox Small pox
Cow Blue tongue virus Blue tongue
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I Cow Herpes virus Herpes

Dog Street rabies virus Rabies

Vaccination
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• It is the process of artificial introduction of gerins or the germ substance called

antigen into the body for developing resistance a particular disease. The material
introduced into the body is called vaccine.
• A vaccine is a dead or weakened microbes. They are unable to produce disease as they
@

are less in number but they stimulate the body to produce antibodies.
• World Health Organisation (WHO) in 1974 officially
launched a global vaccination
programme to protect children fromn six fatal diseases. Diphtheria, pertussis, tetanus,
polio, TB (Tuberculosis) and measles. It was launched in India in 1985.
• BCG (Bacillus Calmette Guerin) vaccine is given to protect against TB (Tuberculosis).
• DPT (diphtheria, Pertussis and Tetanus) vaccine is given to babies within first 6 weeks
of their birth.
Some Vaccines and their Doses
Age Vaocination Dose
Birth to DPT (triple vaccine, against Three doses (commonly oral) at
12 months diptheria, whooping cough/pertussis intervals of 4-6 weeks.
and telanus)
Polio (Sabin's oral, previously Salk's Three doses at intervals of 4-6
injectible)
weeks.
BCG (Bacillus Calmette Guerin) Intradermal and one vaccine
9-15 months Measles vaccine (MMR or Measles, One dose
Munps and Rubella)
448 GENERAL KNOWLEDGE~ General Science

Age Vaocination Dose

8-24 months DPT Booster dose
Polio (oral) Booster dose
Cholera vaccine (can be repeated One
every year before summer)
5-6 years DT (Bivalent vaccine against Booster dose
diphtheria and tetanus)
TAB (vaccine against Salmonella Two doses at intervals of 1-2 months
typhi, S. paratyphi A and S paralyphi
B) or Typhoid Paratyphoid vaccine

10 years Telanus, TAB (typhoid) Boosler dose

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16 years Telanus, TAB Booster dose

a Glance)

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Human Body (At
.
Tolal nunber of muscles in the body 639
Total number of bones in the human body 206
Largest organ of human body Skin
Number of cells in body
ra 75 trillion
Longest bone Fermur (Thigh bone)
Smallest bone Ear-ossicle and stapes
Weight of brain 1424 g
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Blood volume 6.8 L (in 70 kg body)

Normal BP 120/80 Hgm

Hb content in body 500-700 gm

Blood platelets 200000-400000 per cubic mm
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Universal blood donor O Rh-(ve)

Universal blood recipient AB
Blood clotting time 2-5 minutes
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Normal body temperalue 98.4° F or 37°C

Breathing rate 16-20/minute
Dental formula Adult : 2123/2123 = 32
Child : 2120/2120 = 20 milk teeth
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Largest endocrine gland Thyroid

Largest muscle in the body Gluteus maximus (Buttock Muscle)
Greatest regeneration power In liver
Menopause age 40-50 years
Minimum regeneration power In brain cells

MinimUm distance for proper vision 25 om

Pulse rate 72/minute
Normal sperms cOunt 200-350 million/ejaculation
ESR (Eythrocyte Sedimentation Rate) 4-10 min/h
Thinnest skin Conjunctiva
GENERAL KNOWLEDGE ~ General Science 449

Human Genetic Disorders

The important human genetic disorders can be categorised as follows
Human Genetic Disorder due to Autosomal Abnormalities
Disorder Chrornosome Effect
Complement
Down's Trisomy 21 (extra Short stalure, epicanthus, srmall round head, protruding
syndrome chromosome number) lower lip, flattened nasal bridge, mental retardation, short
life, daftiness.
Edward's Trisomy 18 (extra Long but narrow skull, small face, short digits, webbed
syndrorme chromosome number) neck, corneal opacity, mental retardation.

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Cri-du-chat Deletion is short arm of Microcephaly, encrusted distance between eyes, moon
syndrome chromosome 5 face, severe mental deficiency, cat like cry of neonale.

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Patau's Trisomy 13 (extra Lett plate and lip, polydactyl, mental retardation,
syndrome chromosome number) anomalies in dermal pattern, heart viscera and genitalia.

GENETICS
Some Important
It is the study of heredity
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and
variations. The term 'Genetics' was Genetic Terms
coined by W Bateson in 1905. Gregor Phenotype It is the physical appearance of an
Johann Mondel (commonly called individual.
Father of Genetics) proposed three
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Genotype It is the entire genetic complement

laws
of an individual organism.
(a) Law of Dominance It states that
Alleles The two individual genes in a
crossing of plant with red and particular gene pair that occupies same locus
white flower produced plants
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only with red flower ie., (position) on homologous pair of chromosome.

dominant trait and Dominant and Recessive Traits (inherited
ecessive disappeaar character) The traits may be dominant or
recessive depending upon the fact that on
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(b) Law of Segregation It states

crossing the individuals (which are
that allele of a gene separate a samne
during gamete formation. It is homozygous for particular trait of
also called law of purity of character the trait which appears in the
genetics or law of splitting of generation is called dominant and the other
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hybrids. It gives 3: 1 ratio in F, one is recessive.

generation. Hybrid An offspring, which is obtained from a
(c) Laww of Independent CrOSs between two genetically different
Assortment It states that tvo or parents.
more genes assort independently Linkage The phenomenon of genic
during inheritance. It gives 9 :3: inheritance in which genes of a particular
3 : 1 ratio in F generation. chromosome show their tendency to inherit
Linkage is an exception to this together, i.e., tendency to retain their parental
law. combination even in the offsprings is known as
•Test Cross The cross between linkage.
heterozygous F and homozygous Mutation It is a sudden change of a gene (gene
recessive is called test cross. In test mutation) or chromosome (chromosomal
cross, the monohybrid ratio is 1: 1 mutation) from one form to another, which are
and dihybrid ratio is l:1:1:1. passed to the daughter cells.
• Back Cross The cross between Heteroploidy It js the variation in
heterozygous F hybrid and chromosome number.
homozygous dominant allele is Pleiotropy It occurs when One gene
called back cross. influences multiple phenotypic traits.
450 GENERAL KNOWLEDGE~ General Science

Human Genetic Disorder due to Abnormalities

in Sex-Chromosome Number
Narme Chromosormes Effect
Cornplement
Turner's 44+X0 (45) Phenotypically female, sterile due to undifferentiated
syndrome gonads, webbed neck, low posterior hair line
increased carrying angle of elbow, short slature.
Noonan's 44+ YO (45) Phenotypically male, short stature, webbed neck,
syndrome drooping upper eyelid, little development of gonads.
Super males 44+XYY (45) Male, tal, excess testosterone secretions,

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subnormal intelligence.
Super 44+XXX(47) Fermale, mental retardation, low fertility but genitalia
fermales normal.

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44+XXXX(48)
Klinefelter's 44+XXY(47) Male tall with long legs, some with gynecomastia,
syndrome 44+XXYY(48) small testes, azospermia, infertile, increased
excretion of gonadotropin.
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Human Genetic Disorder due to Gene Mutations in Autosomes
(Chromosome that is not a sex chromosome)
Disorder Dorminant/ Autosomal/ Syrmptorms Effect
recessive Sex-linked
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Phenylketonuria Recessive Autosomal Failure of brain to Defective form of

(chromosome 12) develop infancy enzyme phenyl
mental relardation. alanine hydroxylase.
Sickle-cell Recessive Autosomal Aggregation of Abnormal
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anaemia (chromsome 11) erythrocytes, more haemoglobin in

rapid destruction of RBCs
erythrocytes leading
to anaemia.
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Haemophilia Recessive Sex-linked Failure of blood to Defective form of

A/B (X-chromosome) clot. blood clotting factor
VIII/NX.

Colour Recessive Sex-linked Failure to Defect in either red

or/and green cones.
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blindness (X-chromosome) discriminate between

red and green colour.
Huntington's Dorminant Autosomal Gradual degeneration Production of an
disease (chromosome 4) ofbrain tissue in inhibitor of brain cell
middle ages. melabolism.
Cystic tibrosis Recessive Autosomal Mucus clogging in Failure of chloride
(chromosome 7) lungs, liver and ion transport
pancreas anomalies. mechanism.
GENERAL KNOWLEDGE ~ General Science 451

Biotechnology
It deals with technique of using live Golden Rice
micro-organisms, their parts or processes for
. It is a variety of Oryza
sativa (rice)
the manufacture of useful or commercial produced through genetic engineering
substances. It has two core techniques i.e., to biosynthesise beta-carotene,
genetic engineering and technique to precursor of pro-vitamin-A in the
facilitate the growth and multiplication of edible parts of rice. Golden rice was
only desired microbes. In genetic engineering
developed as a fortified food to be used
(also called recombinant DNA technology)
in areas, where there is a shortage of
restriction endonucleases are very useful.

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diet having vitamin-A.
They cleave the DNA at specific locations •
called restriction sites. Golden Rice 2 produces up to 23

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• Vectors are organisms or times more beta-carotene than the
their parts used to original variety of golden rice. Golden
transfer the desired DNA from One rice was created by Ingo Potrykus of
organism to another. The common vectors
are bacteriophage, cosmids, phagemids, the Institute of Plant Sciences at the
Swiss Federal Institute of Technology.
plasmids etc.
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working with Peter Beyer of the
• Polymerase Chain Reaction (PCR) University of Freiburg.
developed by Kary Mullis (1983) can clone •
or amplify the small amount of DNA. It Carotene impart orange colour to
carrots and is the reason why
involves denaturation, primer annealing
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genetically modified rice is golden. For

and polymerisation the definite
the golden rice to make beta-carotene,
sequence.
three new genes are inserted: two from
and the third from a
Applications of Biotechnology daffodils
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bacterium.
A number of transgenic plants, medicines,
acids are produced through genetic FlayT Savr
engineering. By the use of antisense RNA technology
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Bt Cotton the enzyme polygalacto-uronase, which

causes damage to pectin is deactivated
It was developed to reduce the heavy reliance and the tomato is kept fresh for longer
on pesticides. The bacterium Bacillus duration.
thuringiensis (Bt) naturally produces a
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chemical harmful only to a small fraction of Canola

insects.
It is either of rape seed (Brassica napus
Bt Brinjal L) or field mustard (Brassica campestris
L or Brassica rapavar). Its nodes are
It is a transgenic brinjal (also known as an egg used to produce edible oil suitable for
plant or aubergine) created by inserting a consumption by humans and livestock.
crystal protein gene (Cry IAc) from the soil The oil is also suitable as biodiesel.
bacterium Bacillus thuringiensis into the
genome of various brinjal varieties. Dairy Products
• Cheese is prepared by the coagulation
Bacillus thuringiensis (B0) of casein and other minor milk
It is Gram positive, soil-dwelling bacterium, proteins (curdling of milk) by an
commonly used as a biological pesticide. The Cry enzyme rennin extracted from calf
toxin found in the bacterium is extracted and used gastric mucosa.
as a pesticide. It also OccUrs naturally in the gut of
Streptococcus and Lactobacillus
caterpillars of various types of moths and species are involved in the
butterflies, as well as on the dark surfaces of plants. manufacture of most cheese.
 452) GENERAL KNOWLEDGE~General Science

• In cheese manufacture, Biochips allow rapid screening of gene

micro-organisms are important in both profiles, a tool that promises to have a
sOuring and ripening processes. revolutionary impact on medicine and
• Semisoft blue Roquefort cheese of society.
France is produced using the mold •Biochips can help in identifying precise
Penicillium rogueforti. forms of cancer.
• Yoghurt is a preserved milk product Gene therapy is the treatment of disease
having a distinct taste and a thick by replacing, altering or supplementing a
texture than milk. gene whose absence or abnormality is
• Yoghurt is made by fermenting whole responsible for the disease. Gene therapy is
milk with a mixture of Lactobacillus unique as it employs the genetic material,

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bulgaricus, Streptococcus lactis and S. i.e. DNA, itself as the means of treatment.
thermophilus at 40 to 46°C. DNA inger printing is the technique, in

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which the banding pattern of DNA
Vitamins fragments is compared and can be used in
many species, including human, to indicate
• Vitamin C was the first vitamin to be
produced by a fermentation process relativity. (used for rape victim, paternity,
using Acetobacter, a wild bacterium. other criminals).
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• Bacteria used for
industrial production Human insulin or humulin is the first
of vitamin-Bg are propionibacterium genetically engineered pharmaceutical
product, developed by Eli Lilly and
shermanii, P freundenreichii and company in 1982.
Pseudomonas denitrificans. .
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• Vitamin-B, (Riboflavin) is synthesised Genentech, a California-based company,

by many micro-organisms including
have produced human growth hormone
(hGH) from genetically engineered
bacteria, yeasts and fungi. The fungus, bacteria.
Ashbya gossypii is used for the
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microbial produetion of vitamin-B,. Somatostatin is the first polypeptide,

which was expressed in E coli as a part of
Biotechnologies in the fusion peptide.
• BST or Bovine Somatotropin is produced
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Human Health in a large quantity from milk production in

• Monoclonal antibodies are made coWs.
outside the body by the hybrid cell . In 1997, a transgenic cow Rosie'
cultures known as hybridomas. produced human alpha-lactalbumin
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• Monoclonal antibodies (mAb) ale

protein enriched milk (2.4 grams per litre).
antibodies that are identical because It is possible to cure phenylketonuria
they were produced by one type of disease by using recombinant DNA
immune cell and are all clones of a techniques in early period of pregnancy.
single parent cell.
Urokinase is involved in dissolution of
•A biochip is a on discrete collection of blood clots. It has been synthesised in huge
gene fragments a stamp-sized chip
quantity by using genetically engineered
that can be used to screen for the bacteria with urokinase genes.
presence of particular gene variants.
GENERAL KNOWLEDGE ~ General Science 453

Organic Acids Synthesised by Various Microbes

Organic Acid Micro-organism
Lactic acid Lactobacillus delbreuki, L bulgaricus, Streptococous lactis and
Rhizopus species
Acetic acid (vinegar) Acetobactor aceti
Citric acid Aspergillus niger, Penicilliurn sp and Mucor sp.
Gluconic acid Aceobacter aceti, Aspergillus niger, Peniciliurm and Chrysogenum
Propionic acid Propionibacterium
Butyric acid Clostridium acetobutylicum

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Oxalic acid Aspergillus sp.
Gallic acid Aspergillus niger

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Sorme amino acids Escherichia coli

Types of Antibiotic with their Source and Action

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Antibiotics Source Action
Penicilin Penicillium chrysogenum, Tonsiliis, Sore Throat, Gonorrhea,
P notatum + Phenyl Acetic Rheumatic Fever, some Pneumonia types
Acid
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Griseofulvin Penicillium griseofulvum Antiungal, especially for Ringworm

Nystatin Streptomyces noursei Antifungal for Candidiasis and overgrowth
of Intestinal Fungi during excessive
antibiotic treatment.
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Hamycin Streptomyces pimprina Antifungal Antibiotic

Fumagillin Apergillus furnigatus Broad spectrum antibaclerial especially
against Salrmonella and Shigella.
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Bacitracin Bacillus licheniformis Syphilis, Lymphonema or Reticulosis.

Streplomycin Streptomyces griseus Meningitis, Pneumonia, Tuberculosis and
Local Infection. Toxic in some, through
eighth oranial nerve.
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Chlorarmphenicol Streptormyces venezuelae, Typhoid, Typhus, Whooping cough,

Chloromycetin S. lavendulae Atypical Pneumonia, Bacterial Urinary
Infections.

Tetracyclines/ Streptomyces aureofaciens Viral pneumonia, Osteomyelitis,Whooping

Aureomycin Cough. Eye infections.
Oxytetracycline/ Chlorotetracycline Intestinal and Urinary Infections
Terramycin Hydrogenation Streptomyces (Spirochaeles, Ricketsia, Viruses)
rimosuS
Erythromycin Streptomyces erythreus Typhoid, Common Pneumonia,
(= S. erythraeus) Diphtheria, Whooping Cough etc.
Gentaycin Micromonospora purpurea Eftective against Gram (+) bacteria
Polymixin Bacillus polymyxa Antifungal

pasteurised (preserved) by boiling it at 62.8° for 30 minutes (Low Termperature Holding

* Milk is
method or LTH) or at 71.7.°C for 15 seconds (high temperature holding method). These
treatments kill all bacteria.
 454 GENERAL KNOWLEDGE~ General Science

Botany
• It is
the branch of biology which PLANT MORPHOLOGY
deals with plants, which are plant morphology represents a study of the
considered as multicellular development. form and structure of plants and by
ulcerates. The cells of these implication, an attempt to interpret these on the
organisms contain a cell wall basis of similarity of plan and origin.
made up of cellulose and other
polysaccharides. Plants have the Classification of Plants
ability to synthesise their own Plant classification is the placing of known

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food (autotrophic) in the
presence of sunlight, via the plants into groups or categories to show their
process of photosymthesis. relationship.

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.
Plants have two main groups i.e., Thus, plants are classified into group having
same characteristics.
cryptogams (lower plants
without well defined flowers and Thallophyta A phylum of plants of very
diverse habit and structure, e.g., Algae, fungi
seeds) and phanerogams (higher
and lichens.
plants with well defined flowers
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and seeds). Bryophytes Have stems and leaves but lack
• Cryptogams further contains true vascular tissue and reproduce by spores
thallophytes and pteridophytes e.g., Mosses, hornworts, liverworts etc.
with bryophytes in between. Pteridophytes Vascular plants with leaves,
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Here, thallophytes means those stems and roots, but lack both seeds and
plants which have thallus like flowers, e.g., Ferns, Lycopodium, horsetails etc.
body i.e., without roots, leaves Gymnosperms Group of seed producing
and stem e.g., algae, fungi, plants. A plant that has seeds unprotected by an
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bacteria etc. ovary or fruit, e.g., Conifer, cycads, pine tree etc.
• All the plants of cryptogams are
Angiosperms (Vascular plants) A major group
considered as primitive as these of flowering plants. Their characteristics are the
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do not have well defined features

possession of protected seeds or fruits, e.g.,
of plants like presence of phloem Rose, tulip, tomatoes etc.
(a tissue for food transport) and
presence of xylem (a tissue for
water transport etc). Virus
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• Phanerogams are well defined The term virus was given by Pasteur. Virus was
advanced plants vith proper roots, discovered by lwanowski in the extract of diseased
leaves and stem and well tobacco plant. Virus is a nucleoprotein entity which
differentiated tissue system. These not have machinery of its own but can utilise the
can be categorised as synthetic machinery of living cell of other organisms for
Gymnosperms (Naked Seed) and its multiplication. Virus is considered to be a cellular,
(Covered seed) i.e. without a cell.
Angiosperms
plants. Bacteria
Algae like Nostoc, Anabaena etc are Basically, bacteria are unicellular prokaryotes. Their
Used asS manure.
cell wall is generally, made up of peptidoglycans and
polysaccharides. Genetic material is not organised into
Sphagnum a genus of mosses is
nucleus, i.e. a primitive nucleus is present (without a
used as fuel and antiseptic. nuclear membrane). All membrane bound cell

organelles are absent.

• Some plants catch insects to
fulfill their nitrogen requirement. Flagella, if present is single-stranded, made up of
protein flagellin.
Such plants are called
insectivorous plants. Gamete formation is absent.
GENERAL KNOWLEDGE ~General Science 455)

PARTS OF A PLANT Stem

Different parts of a plant perform different It is the ascending organ of the plant,
function. Accordingly they are divided into which is formed by the elongation of
root, stem, leaves, flower, fruits and seeds. plumule. Thus, stem is that part of the
plant, which originates from plumule and
goes towards sunlight opposite to the
Root
It is that part of plant body, which develops ravity.
from radicle and grows down into the earth.
UndergTOund Modifications
It gives secondary and tertiary roots.
Plants have two types of root systems In the adverse conditions underground
stems store their food and become

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1. Tap root develop
from radicle, normally thickened and tuberous.
found in dicot plants.
Various types of modifications can be
2. Adventitious root with a main tap root described

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as
that is larger and grows faster than the Stem
branch roots. tuber Potato
Bulb Onion, garlic, tulips, lilies etc.
Modification of Tap Roots Corm Gladiolus, Crocus sativus
root
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thickened saffron etc.
Conical This type of is
towards base but thin near the side of the Rhizome Ginger, turmeric, arrow root
plant, e.g., Carrot. etc.
Napiform This type of root is very broad at Subaerial Modifications
the top and tapering like a tail at the bottom,
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e.g., turnip, beet root etc. There are various types of modifications
Pusilorm This type of oot is inflated in the etISts im such types of stem
middle portion, while thin towards bottom Runner Grass root, Mereilia etc.
Stolon Mint, jasmine, stravwberry etc.
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and top, e.g., Radish.

Pneumatophores This type of root is found Offset Water hyacinth, Pistia etc.
in salty soil near the sea and for the Sucker Pudira, chrysanthemum etc.
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respiratory activities, it undergoes toward

negative geotropism, e.g., Rhizophora, plant Aerial Modifications
Sundari etc. Various aerial modifications are:
Mycorrhizal These roots are known from Stem tendril Grape
90% of plant species and are mutualistic Stem thorn Lemon, oses, jujube plum
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association of a fungus with plant root tissue. or Chinese date

Most plants require specific mycorrhizal fungi Phylloclade Cactus
without, which they are unable to absorb
sufficient quantities of P Zn and Mn. Bulbils Ruscus.
The fungus takes the place of root hairs and Leaf
may penetrate the cortex completely
(endomnycorrhizae) or remain on the surface It is a green part, its main function is to
of the root (ectomycorrhizae). make food through photosynthesis and
respiration. Leaves are mainly of two
Functions of Root types
• Keeps the plants static. 1. Simple Leaf A leaf having one blade
. but blade is not divided, e.g., mango.
Transports water and mineral salts to the
stem and ultimately to the leaves. 2. Compound Leaf A leaf with more
• than one blade. All blades are
Absorbs water and mineral salts from attached to a single leaf stem, e.g.,
the soil. Rose, orange etc.
 456) GENERAL KNOWLEDGE~General Science

Partsof a Typical Leaf

Leaf Base It is the lowermost part of the leaf, borne onto the node of the stem or its
branches.
Petiole The stalk of leaf that connects the lamina with the stem or its branch is
called petiole.
Lamina It is the terminal, flattened, green and conspicuous part of a leaf and is
specialised to manufacture food (photosynthesis).
Differences between Stem and Root
Stern Root

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Cuticle or cutinised outer walls of epidermal Cuticle or outinised outer walls absent.
cells present.

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Epidermis is protective in function. Epidermis (young) is absorptive in function. It is
called epiblerna or rhizodermis.
Stomata is present in epidermis. Stomata is absent in epiblema.
Stem hairs are additional cells, i.e., they do Root hairs are tubular outgrowths of the epiblerna
not arise as outgrowths of epidernal cells. (epidermal) cells.
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Chloroplasts may be present in some outer Chloroplast almost absent.
cells of the cortex.
Cortex narrow. Cortex broad.
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Endodermis is inconspiCuOus. Endodermis is onspicuOUs.

Pericycle not involved in secondary growth. Pericycle actively involved in root branches
formation and in secondary growth.
Xylern characteristically endarch. Xylem characteristically exarch.
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Xylem and phloem fibres presernt. Xylem and phloem fibres usually absent.
Secondary growth, if occurs, takes place by Secondary growth, if present, takes place by
primary carmbium, which is both secondary cambium, the conjunctive parenchyma
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interfascicular and intrafasoicular. and pericycle slart meristermatic activity and

participate.

Inflorescence Cymose Inflorescence

The arrangement of lowers on a floral n
cymose inflorescence, the main axis ends
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axis is called inflorescence. The portion of in a flower, since the peduncle stops growing.
stem that bear cluster of flowers is called The flowers show basipetal succession.
peduncle and the stalk of individual flower Inflorescence
is called pedicel. The inflorescence has Common Racemose
been classified into five distinct types and thneir Presence
according to modes of branching and Inflorescence Presence
modification of peduncle.
Spike Adhatoda
Solitary
Racemose Spikelet Grasses
Cymose Catkin Morus
Mixed Spadix Banana and maize
Specialized Corymb Iberis amara (candy tuft)
Out of four, two types are most important. Capitulum (head) Sunllower
Special Intlorescence and their
Racemose Inflorescence presence
In racemose inflorescence, the main axis Oyathium Euphorbiaceae family
is capable of continuous growth. The Verticillaster Ocirmum and LeucUs
flowers show acropetal succession on the Hypanthodium Ficus
main axis.
GENERAL KNOWLEDGE ~ General Science 457)

FLOWER Pollination
It is a modified shoot that consists of Transfer of pollens from stamens to stigma
accessary whorls (calyx and corolla) and is called pollination.
essential whorls (androecium and It is of two types
gynoecium). The plant, which bears both
male and female Alower is called Selt-pollination
monoecious, while separate plants with Transfer of pollen from stamen to the
one type of flower are called dioecious. stigma of same flower or different flower of
the same plant.
Calyx
The outermost whorl consisting of units Cross-pollination

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called sepals; these are typically green and In this, pollen reach from anther of one
enclose the rest of the lower in the bud flower to the stigma of different flower of

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stage, however, they can be absent or same species. This is done with the help of
prominent and petal-like in some species. air, water, insects or animals (agents of
pollination). In most flowers, maximum
Corolla pollination occurs by the method of
The next whorl toward the apex, composed anemophily (by mind). In this mode,
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of units called petals, which are typically pollen-loss is maximum.
thin, soft and coloured to attract animals
that help the process of pollination. Fruits
It is ripened ovary of flower. The fruit may
Androecium
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be true (formed from ovary alone) or false

The next whorl, consisting of units called (developed from other part offlower except
stamens. It consist of two parts-a stalk Ovary). These are of three main types,
i.e.

called a filament, topped by an anther, simple, aggregate and composite.

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where pollen is produced by meiosis and Simple Fruit

eventually dispersed.
A simple fruit always develops from a single
Gynoecium ovary containing one or more carpels and
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•
The innermnost whorl of a flower. may or may not include additional
accessory floral (perianth)
modified
consisting of one or more units called
SlTuctures. In addition, a simple fruit is
carpels. The carpel or multiple fused an elther fleshy or dry. Fleshy fruits are edible
carpels form a hollow structure called are seen in the fresh fruit and
ovary which produces ovules internally. and
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• Ovules are megasporangia and they in market.

vegetable section of your local super
turn produce megaspores by meiosis,
which develop into female Aggregate Fruits
gametophytes. These give rise to egg These are groups of simple fruits, developed
cells. from multicarpellary or polycarpellary
• The gynoecium of a flower is also apocarpous ovary of a flower: These are
described using an alternative etaerio of follicle, etaerio of achenes, etaerio
terminology, wherein the structure one of berries and etaerio of drupes.
sees in the innermost whorl (consisting
of an ovary, style and stigma) is called Composite Fruits
a pistil. A
composite or multiple fruit develops from
• A pistil may consist of a single carpel or a the complete inflorescence. These are of

number of carpels fused together. The tUo types

sticky tip of the pistil, the stigma, is the Sorosis A multiple fruit derived from just
receptor of pollen. The supportive stalk, the pistils of many unisexual flowers of an
the style, becomes the pathway for pollen inflorescence, e.g., Mulberry, jackfruit,
tubes to grow from pollen grains pineapple etc.
adhering to the stigma.
 458) GENERAL KNOWLEDGE~ General Science

Syconus A multiple fruit derived from Crop rotation also mitigates the build-up of
numerous ovaries borne on the inside of pathogens and pests that often occurs,
the flesby receptacle of an inflorescence. when one species is continuously cropped
Also in accessory ruit, the fleshy portion of and can also improve soil structure and
the fruit is formed by the hollow peduncle fertility by alternating deep-rooted and
of the (inside-out) inflorescence, e.g., shallow-rooted plants.
peepal, gular.
Intensive Cropping
Seeds It refers to efficient use of water, nutrients
Seed is a fertilised mature ovule that and tillage. The interdependence of and
possesses an embryonic plant. synergies among water, nutrients and
energy in regard to increasing crop

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There are two types of seeds
preferred.
Non-endospermic seeds non-albuminous performance is generally

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seed Endosperm is absent in this seed
and stores their food material in Main Crops for Rotations
cotyledons, e.g., Gram, pea. One yearly Paddy and wheat
Endospermic or albuminous seed These Two yearly Maize and cotton
possess endosperm and store their food in
Three yearly Tomato and lady's finger
it, e.g., Castor, maize, rice.
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Four yearly Cotton and wheat

AGRICULTURE Zero Tillage

• Agriculture is derived from Latin words
It is a way of growing crops from year to year
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Ager and Cultura. Ager means land or

field and Cultura means cultivation. without disturbing the soil through tillage.
Therefore, the term Agriculture means No-tillis an agricultural technique, which
cultivation of land, ie., the science and increases the amount of water and organic
art of producing crops and livestock for matter (nutrients) in the soil and decreases
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economic purposes. erosion. It increases the amount and variety

• It was the key development in the rise of of life in and on the soil.
sedentary human civilisation. whereby t has two distnctive features
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farming of domesticated species created Sole Cropping It is to cultivate a pure

food surpluses that nurtured the variety of crop.
development of civilisation. Monoculture Planting a sole crop in a
field regularly but harvest it single in a
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AGRONOMY year.
The branch of agriculture that deals with Companion Planting/Cropping
field Crop production and soil It is the planting of different crops in
management. Agronomists generally work proximity on the theory that they assist each
with that are grown on a large scale in nutrient uptake, pest control,
(e.g. Small orains) and that require nollination and other factors necessary in
relatively little management. Agonomic increasing crop productivity.
experiments focus on a variety of factors
relating to crop plants, including yield, Intercropping
diseases, cultivation and sensitivity to It is the practice of growing two or more
factors such as climate and soil.
crops in proximity. It is particularly
Cropping Pattern important not to have crops competing with
each other for physical space, nutrients,
Crop Rotation water or sunlight.
It is the practice of growing a series of The most common goal of intercroppirng is
dissimilar types of crops in the same area to produce a greater yield on a given piece of
in sequential seasons. It confers various land by making use of resources that would
benefits to the soil. otherwise not be utilised by a single crop.
GENERAL KNOWLEDGE ~ General Science 459)

Multiple Cropping Organic farming uses fertilisers and

pesticides but strictly limits the use of
It is the practice of growing two or more crops synthetic fertilisers, pesticides, plant
in the same space during a single growing growth regulators such as hormones,
season.
livestock antibiotics, food additives
It can take the form of double-cropping, in and genetically modified organisms.
which a second crop is planted after the first
has been harvested or relay cropping, in which Blanching
the second crop is started amidst the first crop the voung shoots of a plant are
In it.
before it has been harvested. covered to exclude light to prevent
photosynthesis, which would produce
Farming System chlorophyll and thus, remain pale in

e
Mixed Farming colour. Blanched vegetables have a
It is one in which crop production is combined
more delicate flavour and texture than

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with the rearing of livestock. The livestock unblanched.
enterprises are complementary to crop
production, so as to provide balance and
a SEED SCIENCE
productive system of farming. • It is a basic and most important input
ra of agriculture. A good quality seed is
Ranching one, which is free from adulterants,
It is the practice of raising the grazing livestock diseased or insect-pest infestations,
such as cattles, sheep or poultry. The area is which hinder or reduce the quality of
kknown as ranch and the practice is called a seed.
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ranching. The ranching and cowboy tradition .

The era of hybridisation of seeds
originated in Spain. During the Reconquista in started after 1930. The hybrid seeds
middle ages the Spanish nobles got huge lands are the cross breeded seeds, which
on granmts. are artificially developed so as to have
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Terrace Farming the desirable characters. While

developing a hybrid seed, it goes
It is a piece of sloped land, which has been through the various developmental
landscaped in such a way that, the practice of
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stages.
farming can be easily carried out. These are
Generally, this type of farming is done in the
mountain regions along the slope. The land is Nuclear Seed It is initial pure seed
cutout along the slope and terraces are made. of an improved variety available with
@

This system is more common in North-Eastern the breeder.

hilly tracts of India. Breeder's Seed It is the seed
obtained from the progeny
Truck Farming (generation) of nucleus seed.
(Marketing Gardening) -
Foundation Seed The breeder
It is a horticultural practice of growing fruits, seeds grown on State Government
vegetables, etc., on commercial basis, in trucks farms and agriculture umiversities
for direct delivery to big restaurants, hotels and under scientific observations and
motels. This technique was evolved by the check.
english speaking farmers, who referred them Registered Seed The seeds grown
as truck farms in 19th century.
from nucleus, breeder's and
foundation seeds.
Organic Farming
Organic agriculture means a process of Certiied Seed The seeds certified
developing viable and sustainable before release as a new variety
agroecosystem. It is an agricultural practice having all the desirable characters.
that relies on crop rotation, green manure,
compost and biological pest control.
460 GENERAL KNOWLEDGE~ General Science

Synthetic and Composite Traitor Technology

Seed Varieties In this technology, to make the induced
gene active, certain chemicals are used.
• Synthetic variety: It is a variety Many Multi National Corporations
developed by selecting a number of inbred (MNCS) are trying to bring this in India
lines with good General Combinig Ability
(GCA). Synthetic varieties and environmentalists are opposing it.
can be
developed by using clones or inbreeds, Crop
e.g., ICMS 7703. Diversification
• It is intended to give a wider choice in the
Composite variety: It is a variety that is Droduction of a variety crops in a
of given
developed by mixing of seeds of various area so as to expand production related

e
outstanding inbred lines, which have activities on various crops
and also to
similar characteristics. So, the exact lessen risk. Crop diversification in India is
reconstitution of composite variety is not generally viewed as

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shift from
possible, e.g., Sona, Shakti, African tall etc. traditionally grOWn less remunerative
Hybrid Seed Crops to more remunerative crops.
.
It is produced by cross-pollinated plants. AGROFORESTRY
ra
In hybrid seed production, the crosses are
specific and controlled. The advantage of It is an integrated approach of using the
growing hybrid seed compared to inbred interactive benefits from combining trees
lines conmes from heterosis.
and shrubs with crops and/or livestock. It
. To combines agricultural and forestry
produce hybrid seed, elite inbred technologies to create more diverse,
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varieties are crossed with well

productive, profitable, healthy and
documented and consistent phenotypes sustainable land-use systems. A narrow
(such as yield) and the resulting hybrid definition of agroforestry is trees on farms.
seed is collected.
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Vermicomposting
Artificial Seed using worms to transform
Itis a method of
It is encapsulated plant propagule (somatic organic waste into nutrient-rich
jm

embryo/shoot bud) in a suitable matrix, fertiliser. It is a healthy and clean way to

containing substances like nutrients, growtheliminate wastes going into our landfills,
regulators, herbicides, insecticides, which improves the environment.
fungicides and mycorrhizae, which will Vermicomposting is inexpensive and only
allow and help it to grow into a complete talkes two to three months to
produce
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plantlet.
results.
Genetically Modified Seeds Plant Preservation
It is that they have been altered or modified, Like other organisms plants can also be
through biotechnology to have their genetic infected with the disease. All these
structure changed. This is LUSually
accomplished by either adding or taking disease causing agents are called Pests.
Main causative agents are virus, bacteria
away genes of the original.
and fungi. As for example, wheat is
Terminator Seed infected with rust and smut. In paddy
generally blast is found, which is spread by
The term Terminator seeds as it applies to Gandhi bug. In cotton, bollworm causes
the area of agriculture can be defined as a disease.
descriptive term used by some for seeds that Keeping fruits and vegetables fresh for a
have been genetically engineered to produce longer period without hampering its
a crop whose first generation produces
physical and chemical properties, is
sterile seeds, thus preventing a second called fruits and vegetables preservation.
generation from being grown from seeds Essential Commodities Act, 1955 has
saved from the first. Part-3 for its revelation.
GENERAL KNOWLEDGE~General Science 461

Methods of Preservation gaining resistance to chemicals produced

by the plant or applied to the crops. By
Various methods of preservation are not killing all the pests there are some
Low Temperature un-resistant pests left that will dilute any
Microbes become inactive at low temper resistant genes that appear.
ature. We can keep them in freezer:
Preventive Cultural Practices
Pasteurisation Selecting varieties best for local growing
crops is
It is a mild heating treatment at conditions and maintaining healthy
temperatures up to 100°C (which is the the first line of defence, together with plant
as
boiling point of water at elevations up to quarantine and cultural technigues such
crop

e
300 metres above sea level). This method sanitation (e.g., removal of diseased
causes only a slight decrease in taste and plants to prevent spread of infection).

nc
nutritional value. Pasteurised products
therefore spoil faster than sterilised Monitoring
products. Regular observation is the cornerstone of IPM.
Observation is broken into two steps, first
Canning inspection and second, identifhcation. Visual
spore traps and other
ra
There are two primary mnethods of canning inspection, insect and
A hot water bath and pressure canning measurement methods and monitoring tools
are used to monitor pest levels.
which ever method you use, be sure to use
jars with lids made specifically for that Since, insects are cold-blooded, their
technique. Glass canning jars, which are physical development is dependent on the
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reusable, come in various sizes (most are temperature of their environment. Many
single pints or quarts), so cho0se one that insects have had their development cycles
best suits your canning needs. modelled in terms of degree days. Monitor
the degree days of an environment to
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Integrated Pest determime when is the optimal time for a

specific insect's outbreak.
Management (IPM)
It is an ecological approach to agricultural Responsible Pesticide Use
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pest control that integrates

pesticides/herbicides into a management Synthetic pesticides are generally used as
system incorporating a range of practices required and often only at specific times in a
pest life cycle.
for economic control of a pest. An IPM
system is designed around sir basic
@

conponents Locust Control and Research

Acceptable Pest Levels On seeing the grave situation of locust
. attack, a warning centre as, locust warning
The emphasis is on control, not organisation has been created, at Jodhpur.
eradication. IPM programmes irst work It has locust surveillance and monitoring
to establish acceptable pest levels, called through 5 circle offices and 23 outposts.
action thresholds and apply controls if
those thresholds are crossed. IPM holds Mechanical Controls
that wiping out an entire pest population They include simple hand-picking, erecting
is often impossible and the attempt can insect barriers, using traps, vacuuming and
be expensive and environmentally unsafe. illage to disrupt breeding.
•
These thresholds are pest and site
specific, meaning that it may be Biological Controls
acceptable at one site to have a weed The main focus for biological control is on
such as white clover, but at another site promoting beneficial insects that eat target
it may not be acceptable. pests. Biological insecticides, derived from
• By allowing a pest population to survive naturally occurring microorganisms
at a reasonable threshold, selection (e.g., Bt, entomopa-thogenic fungi and
pressure is reduced. This stops the pest entomo- pathogenic nematodes).
462) GENERAL KNOWLEDGE~ General Science

Animal Husbandry
The rearing of animals for specific • Mehsana It is found in Mehsana, Sabar
purposes is called domestication and Kantha, Palanpur and Banaskatha. It
such animals are called domestic gives 8-9 L milk per day. 8-13% fat is
animals. Domestication of animals present in its milk. It is considered as a
started during the hunting and gathering hybrid of Murrah and Surti breeds.
phase of human civilisation. .
Surti It found in Gujarat, South-West
part, Anand, Nadiad and Vadodara. It
BUFFALOES gives on an average 1700 L milk per year.

e
Bubalus bubalis is its scientific name. 8-12% fat is available in its milk.
Generally, it is assumed that India is place • Nagpuri or EIlichpuri It found in
of its origin. There are two types breeds of

nc
Nagpur, Akola and Amrawati. It gives on
buffaloes an average 1000-1200 L milk per year.
7-8% fat is present in its nilk.
Exotic or Marshy •
Tarai It found in Tarai belt of Ramnagar,
These are generally found in Myanmar, Tanakpur. It gives about 900-1200 L milk
Malaysia,
ra
Philippines, Thailand, in a year.
Singapore, Indonesia, China. These are • Manda It found in the boundary of
used for cart mainly. Its breeds are Mondosa and Parlakimedi mountain.
Jerangi, Kuhzestani, Ongole, Sinhala, Male is used for carrying heavy loads.
Manofi, Suinue and Walede.
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• Toda It found on the Nilgiri

mountain in
Aquatic or Indian Tamil Nadu. It gives about 4-8 L milk per
day.
These are heavy or light weighted and
generally preferred to stay in water. It has COWS
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low heat-tolerancce capacity.

These ae again categorised into twUo types Bos Scientific name of cow is Bos indicus and
taurus. In India, 30 varieties of cows are
present. Rearing of cow and bull is preferred
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Heavy Weight Buffaloes

in India. 16% of the world cow and bull are
It includes three breeds present in India.
•Jaffrabadi Its place of origin is Varieties of Cows
supposed to be at Junagarh, Kutch and
Jamnagar of Gujarat. It gives 15-18 L Some varieties of cows are as follows
@

milk per day. Its milk contains 7-9% fat.

•
Humped Indian Breeds
Murrah It found generally in Punjab,
Haryana, Delhi, Rajasthan, Uttar These are high milk-yielding and their calves
are not used for agricultural purposes.
Pradesh etc. It generally gives about 25 L
milk per day. Following are its important breeds
.
Nli Ravi It is found mainly in Sahiwal Actually ound in Mont- Gomari
Ferozpur of Punjab. Horns are small, in Pakistan. In India, it is found in Punjab,
white spots on mouth and head. Gives Delhi, Uttar Pradesh, Madhya Pradesh and
on an average l500-1800 L milk per Bihar. It gives around 2150 L milk in a year.
year. 4-6% is content of fat in its milk.
Red Sindhi Found i Allahabad,
Light Weight Bufffaloes Guwahati, Bengaluru. It gives around 5440
L milk in a year.
It includes following breeds
• Bhadawari It is Gir Generally found in Junagarth,
generally found in Kathiawad, Mumbai, Pune, Ahmedabad,
Etawah, Agra, Gwalior and surrounding Hyderabad. Oxen are very strong.
areas. It gives 4.5 Lmilk per day. 12-14%% 1746 L It gives
milk on an average. Fat content is
fat is found in its milk. Male buffaloes 4-5% in its milk.
are used as load carrying cattle.
GENERAL KNOWLEDGE~General Science 463

Deoni Similar to Gir breed. It gives SHEEP

1600-1650 L milk in a year. Fat content is
4-5% in its milk. There are many breeds of sheep (0vis
aries) in our country. Today sheeps are
Dual Purpose Breeds raised in all parts of the world. Sheep
These breeds give more milk along wih its provides us with wool, skin and mutton.
calf is very useful in ploughing. Followina are A sheep lives for about 13 years.
its breeds
. Exotic Breeds of Sheep
Haryana It found in Rohtak, Haryana. It •
give 1000-1100 Lmilk in a year. Maximun Merino This is the main
milk yielding capacity is 3178 kg/yr Calf is representative of the Merino breed in

e
best for ploughing activities. Australia and is found in extremely
• Nimari It mainly found in Khargaun. high number throughout New South
Wales, Queensland, Victoria and

nc
Oxen are very strong. Western Australia.
• Tharparkar It mainly found in Kutch, South Devon The South Devon is a
Marwar and Northern Mumbai. It is also
in longwool and meat breed which
known as Thari. Its average milk yielding originated in South Devon and
capacity is 1474 kg. Cornwall in England. They are of the
ra
English Longwool type and are similar
Load Carrying Breeds to Devon Longwoolled but are larger.
.
Nageri Main place of origin is believed to Both sexes are polled and are naturally
be Rajasthan. Now maximum found in hornless.
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Haryana, Uttar Pradesh and Punjab. Lincoln It is found in England and it

Famous for fast walk and heavy load. is useful for wool and meat.
• Malvi Main place of origin is Uttar
Corriedale It is mainly found in New
Pradesh, now also found in Madhya Zealand and Australia. It is useful for
ie

Pradesh and in Rajasthan.

wool and meat.
• Amritmahal It found în Mysore of Romney Marshy The Romney
Karnataka. These breeds are fast running Marshy are found in England.
jm

and quick.
Romney wool has the finest fibre
• Gangatiri Main place of origin is Uttar diameter of all the longwool breeds.
Pradesh. These are very Iseful for These are mainly used for wool
agricultural practices. production.
• Siri It basically a hilly breed. Found in
@

Darjeeling and Sikkimn. Used in carrying Shearing of Wool

heavy loads. It is essential to promote the health of
Without Humped Cows sheep. The removal of hairs (wvool) from
the recommended periods for shearing
(Exotic Breeds) of wool are winter (February-March) and
rainy (August- September) season when
Milk rielding Breeds rich grazing ground is available.
• Jersey Its colour is almond and body is, The sheeps are washed properly before
spotted, milk yielding capacity is 4500 L per the xemoval of hairs. The manufacture
year 5% fat content in its milk.
of wool from sheep hairs is a
Brown Swiss It mainly found in complicated process consisting of
Switzerland. It gives 5200L milk in a year. cleaning, drying, bleaching, dyeing,
Fat content is 4%. spining and twisting.
464 GENERAL KNOWLEDGE~General Science

GOAT PIGS
There are many breeds of goat (Capra It is also called hog or swine and is an
capra) in our country. Goat provide us omnivorous, non-ruminant, gregarious
milk, meat, skin and hair. The fine soft . mammal of genus Sus.
wool called Pashmina is the underfur of All breeds of pigs have descended from the
Kashmir and Tibet goats. European wild boar Sus scrofa or a
crossbreed of this and the Asiatic species,
Noori S. indicus. The care and management of
World's first Pashmina goat clone, pigs is called piggery.
produced in Kashmir has been named • Pigs are the most prolific breeders and
Noori and Arabic word referring to light.

e
quick growers among the domestic animals.
Funded by world bank, the clone project
A group of 10 sOws (female hog) and
one
was a jointy worked on Skaust and Nari
boar may produce over a year.

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Karnal. 160 piglets in
• Pigs are most useful domestic animals,
The clone has come as good news for
fine fibre producing Pashmina goats, especially of lower classes of society. They
are only spotted at an are most economical sOurce of meat and
which altitude of
14,000 feet in Ladakh. animal fat.
ra
Breeds of Pig
Asom Hilly Breeds
These are smaller dwarf breeds of goats Dormesticated Distribution
found in the hilly tract of Asom and Indigenous Pigs
nt

other Eastern states. Ghori Manipur, Asom, Meghalaya

and Arunachal Pradesh
Important Breeds of
Desi Uttar Pradesh, Bihar, Punjab
Indian Goats and Madhya Pradesh
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Breeds Distribution Exotic Pigs

Gaddi and Himachal Pradesh Landrace Switzerland and Denmark
Chamba Large White UK
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Kashmiri and Himachal Pradesh, Yorkshire

Pashmina Kashmir and Tibet
Berkshire UK
Jamunapari Uttar Pradesh and
Madhya Pradesh
CAMELS
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Beetal Punjab
Marwari Rajasthan The camel is a large, horn less, ruminant
Berari Maharashtra mammal of genus Camelus. It is popularly
called the ship of the desert because of its
Malabari Kerala great travelling power in a desert.
Bengal Bihar and Odisha It is a valuable beast carrying burden in hot
desert and semi-desert regions as it can live on
Exotic Breeds of Goat minimum food and water when travelling with
Exotic breeds of Goats are load. There are two types of camels
• Saahen Alpine 1. Arabian camels (Camelus dromedarius)
Nubian Angora
With a single hump, short hair and found
Mubende in North Africa to India. It does not occur
Boer in wild form.
Sudan Nubian Kambing
Katjang
2. Turksh or Bactrian camels (Camelus
• Toggenburg bactrianus) With two humps, long hair
Khursani and found in Gobi desert of Central Asia.
•
Baluchi Anglo Nubian It occurs in wild form also.
 COMPUTER
INTRODUCTION Alan Mathison Turing is widely regarded as
The word computer has been derived from the Father of Modern Computers or Father
the Latin word 'COMPUTARE'. which of theortical computer science and Artificial
means to compute or to calculate. Intelligence (Al).
A computer can be defined as an Characteristics
of Computer
electronic device used to calculate and • Accuracy
manipulate the data (i.e. input) and Speed

e
Diligence • Versatility
generates an output in the form of useful
information by following a set of
Applications of Computer

nc
procedural instructions.
British scientist Charles Babbage is Education
considered as the Father of Computer. Hospitals
He invented the first mechanical . Business
computer in early 19th centur and
ra Weather forecasting
further in 1833, he conceived a automatic •
analytical engine for performing Entertainment
• Organisations
arithmetic functions.
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Generations of Computer
The history of computers is discussed in terms of different generations of computer.
Generation Technology Features Processing Exarnples Languages
ie

Used Speed
First Vacuum Magnetic drumfor Measured in Mark-1, Machine
(1940-1956) Tubes primary storage miliseconds UNIVAC, language
or Valves Punch card used as ENIAC
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secondary storage
Second Transistor Magnet core memory Measured in IBM-700, Assembly
(1956-1963) used as internal storage microseconds IBM 1401 language
Magnet tapes Used as and HLL
secondary storage (FORTRAN,
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COBOL)
Third Semiconductor memory Measured in IBM 360 HLL
(1964-1971) (Integraled Used as primary storage nanoseconds series, (SNOBOL,
Circuit) Magnetic disks were ICL 1901 BASIC)
used as secondary
storage
Fourth VLSI or Massive use of Measured in IBM PC, HLL
(1971 Microprocess magnetic and optical picoseconds Pentium (ORACLE,
Present) storage devices and beyond. PC, APPLE, ÉDA)
Macintosh.
Fifth Bio-chips Artiticial intelligence will Very high Robolics Natural
(Present & & ULSI make computer speed Language
Beyond) intelligent and
knowledge based
466 GENERAL KNOWLEDGE~ General Science

Types of Computer • Mini Computers This type of computers are

more powerful than micro computers, but
Computer can be classified on three less powerful than mainframe computers.
basis They are also termed as mid-range computers.
On the Basis of Functioms It is a muliprocessing system capable of
supporting 4 to about 200 users
• Analog Computers This is a type simultaneously. e.g. IBM mid range
of computer that reads data using computers, K-202, SDS-92 etc.
measurement and some program .
Mainframe Computers It is a very large
scale. It calculates by measuring computer and is used for handling major
continuous changes in the physical applications in large business organisations.
quantities. e.g. Mechanical They can also be used as centralised

e
integrators, nomogam, computers with several terminal users
speedometer etc. connected to it. They can contain large

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• Digital Computers This is databases and are also knoWTI as super
computer that performs calculations serve'S.
and logical operations with They cai handle huge amount of
quantities represented as binary input/output (I/O) operations at the same
digits. e.g. Desktop, mainframe etc. time. They are very expernsive. e.g. Fujitsu's
ra
• Hybrid Computers These ICL VME, Hitachi's Z800 etc.
computers are the combination of Super Computers It can be defined as the
both analog and digital computers. It most powerful computer in terms of
works by measuring quantity and performance and storage capacity. They are
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calculating logical operations. e.g. highly expensive and are employed for
ECG monitors, HRS-100 etc. specialised applications such as for weather
forecasting, several scientific researches etc.
On the Basis of Purposes NASA (National Aeronautics for Space
ie

•
General Purpose Computers This Administration) uses super computers for
type of computers are designed in launching space shuttles, controlling them
order to work in all environments. and for space exploration purpose.
They are versatile computers but are PARAM is the first super computer in India. It
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not efficient and als0 consume a is a series of gigaflops developed by the Centre
large amount of time in generating of Development of Advanced Computing
(C-DAC), Pune.
the results. e.g. ENIAC, desktops
.
etc. Super Computers Developed in India
@

Special Purpose Computers They Super Year Mft Company

are designed to perform only a
Cornputers
specified task. They are not versatile IIT,
Gandhinagar
Param Anant 2022
and their speed and size depends on Paran Siddhi 2020 C-DAC, Pune
the task. They are efficient and Param Shivay IIT, BHU
consume less time in generating 2019
Pratyush 2017 IITM, Pune
results. e.g. ATM, aircraft controllers PARAM C-DAC and NIT
2016
etc. Kanchenjunga Sikkim
PARAM ISHAN 2016 C-DAC and I|T
On the Basis of Size and Guwahati
Capability Aaditya 2013 Indian Institute of
Tropical Meleorology
• Micro Computers It is a digital PARAM YUVAlI|
C-DAC, Pune
Computer used by individuals and is 2013
also considered as an acronym for SAGA-220 2011 ISRO
Personal Computers (PCs). They are ANUPAM-Adhya 2010-11 BARC
small in ize. They are usually used PARAM YUVA 2008 C-DAC, Pune
Computational
at homes, in schools and offices etc. EKA 2007
e.g. Laptop, Palmtop, Notebook, Research
Laboratories, Pune
Desktop etc. PARAM SAAITA C-DAC, Pune
2007
GENERAL KNOWLEDGE~General Science 467
Top 10 Super Computers of World
Nane Manufactured Country Operating Mernory Speed
Company System
Frontier Hewlett Packard USA HPE Cray OS
Enterprise Frontier
Fugaku Japan Linux
Frontera Texas Advanced America Linux
Computing Centre
IBM Summit America IBM
Sunway Taihu Light National Super China Linux 1.31 PB 105 Pela flops
(2016) computing center
Tianhe-2 (2013)

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Sun Yat-Sen China Kylin LinUx 1,375 TB 33.86 Pelaflops
University
Tilan (2012) Oak Ridge National America Linux 693.5 TB 17.59 Petaflops

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Laboratory(Cray)
Sequoia (2011) IBM America Linux 1,572,864 GB 12 Pelallops
K-computer (2011) Fujiler Japan Linux 1,410,048 GB 10.5 Pelaflops
Mira (2010) IBM America Linux 8.16 Pelaflops
Piz Diant (2009) Cray INC
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Switzerland Linux 6.2 Pelaflops
Stampede (2008) Dell America Linux 192,192 GB 5.2 Pelallops
JU Queen (2007) IBM Germany Linux 458.752 GB 5 Pelallops
VULCAN (2005) IBM America Linux 393,216 GB 4.3 Pelallops
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Components of Computer 2. Output Unit

The computer system comprises of the This unit contains those devices that
following four main components provide the desired output (results) in
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the human acceptable format.

1. Input Unit
output devices are
It consists of those devices through which
.Some
Monitor is also known as Visual Display
User can a
enter the data into computer. It Unit (VDU). The monitor is provided
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links a computer to the external along with the computer to view the
environment. It translates the data into display result. The popular types of
computers understandable form. Some input monitor are
devices are • LCD (Liquid Crystal Display), a special
• Keyboard is used to enter or Lype of liquid is sandwiched between
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data
information, which may be in numeric
LWO
plates. It is a thin, lat and light
form or alphabetical form, in a computer weight screen made up of any number
or
of colour monochrome pixels
system.
• Mouse is a pointing device which provides arranged in front of a light sOurce.
a means to input data and commands in • LED (Liquid/Light Emitted Diode) is
an electronic device that emits light
graphic form by selecting through moving
an arrow called pointer. when electrical current is passed
• through it.
Trackball is another pointing device which • TFT (Thin Film Transistor) is a LCD
is an alternative to a mouse.
• Joystick is an input device that moves in all with active-matrix displays, each pixel
is controlled by one to four ransistors
directions and controls the movement of
that can make the screen faster,
the cursor. brighter, more colorful than
•
Scanner is an optical input device and passive-nmatrix and capable of being
uses light as an input source to convert an viewed at different angles.
image into an electronic form that can be • 3-D Monitors describe an image that
stored on the computer. provides the perception of length.
• Touch Screen is an electronic visual When 3-D images are made interactive
display that can detect the presence and then user feel involved with the scene,
location of a touch within the display area. and this experience is called virtual
reality.