Thursday, August 27, 2020

The fundamental unit of life

The fundamental unit of life


2.1. WHAT IS THE LIVING thes

Wno 10ok different fr

earth is inhabited organisms, very

by different kinds of living was-

eubacterla, protista (Amoe

ter. hese living num

organisms archaebacteria,

are

living organisms are made up of microscon

L ), Tungi, plants and animals. The bodies of

atonm in the physical sciences. The

Lne cell has same central position in biology as an

1s the basic structural and functional unit of living organisms.

DNA tha

day cells share instance, all cells employ as

common fundamental properties. For the

genetic material, membrane, basic mechanisms for ener

are surrounded by and the same

a plasma use

metabolism. On the other hand, present-day cells have evolved a variety of diferent life-styles. Ma Re

Organisms, such as bacteria (both archaebacteria and eubacteria), protozoa (e8, amoeba) and yea

sists of single cells (called unicellular organisms) that are capable of independent sel-replicatio

C cOmplex organisms, called multicell ular organisms, are composed of collections of cells th

Lnclon in a coordinated manner, with different cells specialized to perform the particular tasks. T

Doay, for example, is composed of more than 200 different kinds of cells, each specialized

c dstinctive functions as memory, sight, movement and digestion. The diversity exhibited by

ltny irterent kinds of cells is striking; for example, consider the differences between bacteria and

cells of human brain.

All cells, whether they exists as one celled organisms (unicellular organisms) or as a part

mulicellular organisms are capable of carrying out certain basic functions such as nutrition, respiratie

rowth and reproduction. These functions are essential for the survival of the cells.


Discovery of cell

i ar org umber t o

adidual s short s The

5he espan ot e

n he orgsbon atn hasic d sf Cell biolngy

The fandamental most important stractral and pudae

are the anpects and c structure and fndos

is the study ot oels in al of

Discovery of Cell Hooke saw tat me cis

5a o

strucar consisting Se ot cork, Hobert

of ma eear ments. s a

1665 when ed

his cru e tained disconery from the bark selt ot a e Fig 21) Eooet

through

lsCell a means oBox

bvng 21) Robert s c sed

orga

he ant. in indicated n of a

it L that

of because for he the irst first time time

smaller strue or units

Bax 21 studygea

Cell Theo

The word cell is derived trom

ile atin room". word 'cellula English w reservor

An

Robert Hooke (1639

1665 discovered and re

ells, while examinig iitive

f bottle cork un ade by onev- (Fig screw

21), microscope observed mad

Hooke co . bec

ombed

fo or porous rous strucure re of cork

Hooke s and

pubiis Figure 6. Dead cork cels

cells. He Hooke. as seen

led to p

resemble with blished microscope.

the un Hooke Rober

vork in a DOOK "Micro8e Figure 2.l. Robert s by

tmprOved micrOScope

1663. Durch microscOpist, nond made an

Leeuwenhoek uwenhoes ttb32-1/3, overed the a water

free ans, d rabbits, To irogs, ich tust and insect

n In 1674, T6/4, Anton von this microscope

discovere identied ified

2.3) he ana ered

1678, 

(sCIENC FOR NINR CLASs

leoid.

a

Datterences beetween nucieds Naucleoid

aDie L. comparatively smaier

Ncies absent. in stze THE PUNOAMEN

1 t is theore is t. It it lhes lies free f re

t t

has is larger covering in size. membrane enve 2 A covenng asm

a of double

Nucie absent in lt become

3. lus is to to a a sin slngle DN Ao occurs irre

Euglena in

5. Nucleolus equa anda m

is present i Oanucleoid the

absent. DA membtahe cel sha.

to two or several DN 4. Its DNA contermt s

molecules ts DNA content is equal

associated with histone proteins to In it histones are S pa

chromatin A1s nalkea sms,

human being ca surface

Division of Labour organism such as à

e Figure 2.10, you will notice that an cel,

ells of different Li eg--hdiverse ner rigidity mechanical ter-

osteocyte (ooneE ce u o

Sperm, leucocyte (white blood cell),

labour within mlrtcentlu oguss, ese st

functtons. nuttatt Doay has

utrerernt the tact that there is

human a division of

perform ditterent movement and locomoion and Or pigme

tO pump blood, d stomach t parts of body

to digest food, yuuucaly

cells skeletal muscles muscles to perform contract raplay hythmical

al type of muscle called cardiac which sucn ds mucoous

ssly they special cells proenaye Ot p

Secrete never fatigue during life time of an organism. Stomach has

mucus for lubricating the food, nyarocnlonic

pepsiogen, zymogen cells (or Chief cells) to secrete a

parietal cells oxyntic cells to secrete

(HCI) activatino P, caled or killing germs of food. Skeletal muscle

striated pepsin and also for

and vont nto runctional

contraction depends on your will or corntrol. Dute to uus PrOp

or skeletal their

muscle y muscles,

cells, 1.e,

Lil you are able to move your hands and ten fingers in aes ways.

components e human body, the cell itself has got division of labour. In fact, each cell has got certaln Spe

within it known as cell organelles (Table 2.5). Each kind of cell organelle pertor

t starch) synthesis laKIng of

by new material in the cell such as protein synthesis by ribosomes, fooa (8u

chloroplasts,

nus, cell clearing

a is able to live and perform functions up the waste substances from the cell by the lyscOsomes

its because of these organelles. These organelles toge

cOnstitute the basic building blocks called cells. Quite interestingly, all cells are designed to have the s

c structure, no matter what their function is or what organism they are tound in.

lable 2.5. Differences between organs and organelles.

Organs Organelles

hey are found in multicellular organisms.

hey 1. They are found in all eukaryotic cells.

are large sized or macroscoplc. 2. They are very small sized, either microscopic or Ce

3. They submicroScopic.

may be external

organismns. or internal to the body of an 3. They are mostly internal (i.e., intracellular). cel

4. The mi

organs are formed of tissues, (

of cells arnd cells tissues

formed comprise

are organelles. .

of An organelle is made up of micromolecules

. Organs macromolecules. and

coordinate to form organ systems,

Organ while 5. Organelles

systems form the body coordinate

of an organism. to produce the cell.

Cell Shape

The basic shape of eukaryotic

function of the cell

cell. is spherical,

Thus,

Variable the shape but the shape

irregular of the cell of cell

or shape be is ultimately

may variable determined

occurs in Amoeba (i.e.,

(Fig. frequently by the speu

2.9) and white changing

blood cells its shape)

leucocytes. or th

or In fact, leucoc

alogy


80 movement of

the spontaneous

Thus, diffusion is concentration to one of

of high

molecules from a region concentration is finally

until uniform in Amoeba

lower concentration, phase than

faster in the gaseous cell

achieved. Diffusion is

liquids and solids. Activity 2.3diffusion of ink in

Something similar to such CO2 gets

flor example, a gas ashappens in cells when the

 inside a cell. n

accumulated in high of CO2 islcell, the concentrationexternal environment of there lis a

nside of the cell. As soon asow compared to of

as outside aconcentration of CO%, inside anddifference of from region of its high D

of the cell, i.e., Figure 2.16.

cell, CO2 moves out concentration by the process di

concentration to region of low.



 the cell O

similar way, oxygen (O,)when

of diffusion. In a of diffusion2.16) by the process(e.g., Amoeba ; Fig. cell decreases.

concentration of O2 inside the

the level or diffusion. Thealso follows the law of

2. Osmosis. Water through selectivewater molecules 



spontaneous movement of called osmosis.

plasma membrane) is

permeable membrane (e.g., cell is

plasma membrane of the

across the osmosis

The movement of water Thus,

substance dissolved in water.

affected by amount of through

water concentration

from region of high (Fig.

is the passage of water a concentrations

region of low water

semi-permeable membrane to a by which

a diffusion process

purely mechanical

2.17). Osmosis is a amount of energy.

without spending any

cells absorb water animal cell (e-g,

will happen if you put an

Let what into

us see (eg., Rheo leaves) a

RBCs) cells

or plant following

red blood cells or of the

prepared in water ? One

solution of sugar or salt

happen:

three things could higher water

the cell has a

medium surrounding solution,

1. If the dilute

i.e., if solution is a very

concentration than the cell, solution is called

Such dilute

water by osmosis. a

the cell will gain

hypotonic solution. plasma membrane

free to pass across the

The net

While water molecules are than leave.

will enter the cell

directions, more water situation, celln both the cell. In such ahat water enters 2.18A). Such(over all) result isinflated turgid (Fig.ie., become orhaemolysed. (Fig. 2.19B).is likely to swell up,ultimately burst, i.e.,swollen RBCs may exactly the samethe cell is ofmedium surrounding movement of2. If the there will be no netconcentrationthe cell, Fig. 2.19 A).

water as (Fig. 2.18B andplasma membrane solutionwater across the solution (eg, Ringer'scalled isotonicSuch solution isa cells).solution for the animalbothmembrane inwater crosses the movementIn this case, overallgoing out, so there is nosame as the amountmaintain the same size.

Wednesday, August 26, 2020

Improvement in our food

Improvement in our food


Food Resources

For their existence, all living organisms essentially require food. Early human beings started hunting

animals and collecting fruits, flowers and roots of forest plants to meet their food requirements. Food is

required for growth, development and body repair. It also protects the body from diseases and provides

energy for doing all life functions. For example, food supplies proteins, carbohydrates and fats (lipids),

vitamins, minerals and water to our body.

Among all the living organisms, only green plants are autotrophs, i.e., they make their own food.

In fact, green plants perform a basic metabolic activity, called photosynthesis. In photosynthesis by

using the energy of sunlight, green plants combine carbon dioxide (CO2) and water (H2O) to produce

carbohydrates (Food). In contrast to green plants, animals and human beings are heterotrophs, i.e., they

depend on plants and other animals for food. Since time immemorial, human beings have been doing

farming and rearing animals to meet their food requirements.

Plants as food are gift of nature to humans and most animals. In fact, different parts of plants, such

as root, stem, leaf, flower and fruit, are consumed by humans in the form of cereals, vegetables, spices

and fruits. Animals produce milk, egg, meat, etc., which also supplement our food requirements.

1.1. SUSTAINABLE AGRICULTURE AND ORGANIC FARMING

With 1.04 billion people, our country ranks second in population growth around the world. According to

an estimate, by the year 2020, Indian population would rise to 1.343 billion. To feed such a huge population,

we will require at least 241 million tonnes of grain production per annum. Therefore, it is necessary to

increase production of both, plants and animals. Even in the past, to meet the demands of growing Indian

population, our scientists (such as Swaminathan, Kurein) adapted methods to increase food production. This

resulted in a variety of ' revolutions', which helped India become self-reliant. These revolutions include:

green revolution (high production of food grains), blue revolution (enhanced fish production), white

S: BIOLO

IMPROVEMENTS IN FOOD RESOURCES

improve In India crops

nipulati farmers. Keeping are in grown mind in diverse types of soil and different climatic conditions by poor to progressive

as to be adaptability, etc., a large number climatic factors, input application, disease and pest resistance, quality and

and of varieties have been developed in

DN high yielding and resistant to diseases and pests; they have better quality India and (Table early 1.7 to). late These maturing varieties time are

1 selectis Table 1.7. Improved varieties or high yielding varieties

improvi Commodities Сторы (HYV) of some important crop plants

1. Cereals Varieties

1. Rice

provere IR B, Jaya, Heera, VL Dhan 221.C ST 7-1, Jawahar

ection Pusa Basmati 1, Kasturi, Vikas, TRC-C10, TR 36

an 2. Wheat MIKS 11 KML 7406, HUW 318., MACS PNR-591 2496-18. HD Padma 2687 HD 2285 C 306

hon PBW 154, HW 157, Pusa Lerma,

to 3. Maize Sharbati Sonora

r growi 2. Pulses 1. Chick pea (gram) BE Ganga 244, 5 ICC, HTM128 34, K, 850 Shaldi, H, 208 Navjot, Pusa, Vikram 2: 0. Pant 174

nent 2. Pigeon pea ICPH

wi 3. 8, Pusa Ageti, UPAS 120. Pusa 84 Manak. 121

paya, et Urad bean LB G 17, ADT 3, T9 Pant 4301, PS 1. C05

3. Oil seeds 1. 3. 2. 4 1., Mustard Sunflower Soyabean Groundnut Moong bean PK BSH Pusa MH MLZ 262 2 1 Bold 67,,, MSF ICGS PK, CO4, Kranti 327 H8 1,,, PS M37, Pusa Morden, 16 Pusat,, GG 58 24,, Agarni T 11 Durga, Arun 44, TMV, K851,,, RIM514 Gaurav Paras 12., Aasha Kaushal, RH30, ICGS 11,1CGS 44

plani

is havi

itters

ixed an 4. Mutation breeding. Mutations

rocess through gamma irradiation are sudden inheritable variations. They are produced at random

chieved higher mutations grained dwarf 5. Polyploidy yields Mexican forms by, selective eg (c.8 varieties.. potato, It Pusa is hybridization increasing Lerma of and wheat, Sharbati a the number. were They chromosome developed were Sonora of other, however) through physical number by, N.E. red mutation. and grained Borlaugh Polyploids chemical. carried The are (same agents 1963 out generally) were through by called gamma converted more mutagens incorporation irradiation robust into. amber Triple with of

te for

such

bage

cauliflower Such crop thuringiensis so as 6. which transgenic to DNA modify, cabbage carries recombinant whose the food latter, genes bacterial plants etc.,, They technology to are are get genes used are called protection called by that. genetically This transgenic genetically protect technology from plants their modified crops modified insect refers with such food transfer pests insects as organisms (cotton GMFs.. of Bt, genes). rice (stands GMOs Bt, cotton mize from for), or is one potato the transgenic a genetically organism bacterium, tomato organisms to modified, another brinjal Bacillus,.

ybrid (3) Crop Protection Management

ding

the number weeds economic crops Field, insects of to crops loss insect the, by mites are extent pests destroying infested, nematodes of and 50 diseases with to crop 70, a per rodents variety plants. If cent these,. or of fungi pests pests products, bacteria are. A not pest obtained controlled and is any viruses from destructive at. them appropriate Field. organism crops Pests of are time crop which infested they plants causes can by damage include a great large

of are kill weedicides and these sprayed pests There effective toxic, eg are (on, for chemicals methods weeds various crop killing, plants insects methods is the (pesticides the weeds or, use mites used by of),) and pesticides which rodents as for they fungicides treating insects and cause or biocides fungi seeds and environmental (for diseases are and killing which called soil the. can pesticides include However pollution fungi be controlled). insecticides Thus,.. one These In, fact should chemicals. One chemicals, it (would for of try killing the (to poisons (be most ie avoid, far the pesticides common) better the insects used use to if)),



Other living organisms

Control
IL Insect Pest plants. They at
serious pests of
Many insects are following three ways:
plants in the
attack the crop chewing insects
insects. The
1. Chewing root,
plants. They cut
destroy all sort of crop ot their
plants by the help
stem and leaf of crop insects tear
Thus, chewing
chewing mouth parts.
chew them
delicate branches,
off bits of leaves,
locusts, grasshoppers
and then swallow them, e,g.,
(Hieroglyphus), caterpillars, grubs, etc.
sucking insects suck
2. Sucking insects. The
of the plant. They
the cell sap from various parts
of plants such
include various common pests crop
plant
Aphis), leaf hoppers (Pyrilla),
as aphids (eg.,
painted bug Bagrada
bugs (Gundhi bug of rice, or
red cotton bug or
of cruciferous plants, and
piercing-sucking mouth
Dysdercus). They possess
fine punctures in the
parts. Sucking insects make
needle-like, hollow
skin of the plants with their
beaks and suck the sap.
feeders live
3. Internal feeders. The internal
when
inside the plant parts. They are called borers
they live in twigs borers.
or roots as sugarcane
and fe
Pod borer make holes in pods of chick pea
they attack the fruits and seeds such as cotton-boll
inside the fruits such as guava, ber, karela, ghia tori,
Further, grubs (larvae of beetle) and termites
sugarcane) attack the root zone of crops and then
Infestation of different types of insect pests ca
(i) Root cutting types of insects are controlled
(i) Stem and leaf cutting and boring type of inse
the contact insecticides (Table 1.8), e.g., ma
(ii) All sap sucking insects can be controlled
dimethoate and metasystox. An insecticide
and passing through the tissues is called sv

SCIENCE FOR FOR N NINTH CLASS
aquatic MP
economic va value) lue) aquatnc Plants and, IMP
pe
high ea weeds
(1.e, of ov country country's by Tood Poper outb us
yoedd s
usetul , nume inland water
Aquacuiture r useful mussecreasi musseis ncreisng the merous
shrimp 5,
pertains Crayfish. to lo colstie 1 che
Aquaculture CTalb8, or
cotnercial cial basis basis Includen plan
waters Teis nportant means
cralyi an imp lengthy lengthy fisheries
ach as fishes, prawns, reDecause ot a culture ihaid ort The mnga
of ailabie freshwater 5.
of
coastal waters carps includ com
has a great potential tor the and
cultured m 1hese Kashmir carps inchude the o he
Aquaculture includes maricul dre lakes. These
in other
Mariculture. The Sardinee establlsned
POS, sardines, marine ospects in hed in Kasnu ad
and ns have pr
pearl spots, eel been
hatcheries has good
of exotic carps fishery(T0) (io) fishen
Freshwater shery tishery; pond
trouts. Trout lacustrine
carp, antry.IntrOduction of
carp, bnglish English carp, ea tench and
fishery; (ii) lake or Waters h
(i) reserv expansion in our et waters havep
3. Inland Fisheries iing southern
It includes () riverine fishery ; ) reservoir
fisheries nor
transplantation are rapidly
fish from inland heries. Construction
damage
Inland capture of affectng e nense to hske
Practio A Silver ca
O estuarine fishery. inter-regional adversely also causig aqulacuitare
es tom abroad and pollunon of Indiscriminate water is fishing 1s wever, through culture. Fish
o De great boon. fisheries. inland resoue , paddy-cu
from stem farming 15 compostte tish
ed many n Increasing
regional is include include paddy-cum-fish nThese species h
ot fish production advantageous culture system six
edire most combination of p
with agriculture he Box 1.25. SOme interestinggood
table fish production, up Important factors t
culture co and also taken
gated fish system culture is Det
fish systems have
steel, which which are
1tadc e bamboo or are towelcu nnutrients. of pond ; (1) Water re
x4). Difterent types of The time o
culture systems are rollowin8 tavourahl
in large cages, made of 1S most
1.Cage culture. Fish is cultured such as p Qualita
species are cultured n cog some agcuitara crops
poultry Or PissThe Culture
nver Generally, carnivorous culture is practiced along with uie POuly Or piggen g
2ntegrated fish culture. Fish cultured n ponas ear
higher yield. Fish is also
nana and coconut to give
used as tood in ponds. chniq
the excreta of these animals is
ox 1.26
Paddy-cum-lish culture through This This teehnique of in
Llrrninus fish culture
paddy helds include Cata catia, Labeo rontta, abiebreeding. This tech
The fish species that can be stocked in are
spp., Lates calcarirer, etc. hese species
Clarias Mugil
spp. (catfish), Channa spp. (murrels),
able to tolerate high temperature or turbidity.
in shallow water of paddy fields and During educa
(Polyculture of Fish) Indian carps) and.
4. Composite Fish Culture
monoculture) using old ta 1. Varieties or
Fish production by culturing a singie species in à pond (called
pond, the pro 2. Types Ingredients and
methods gives a low yield ; Dut several Species or nsh are stocked together in a
3.
increases with the same cost. Fience t is ecessalry to Select species having different feeding nab
4. What is th
all the available food in the pond is etfectvely utilised. Fast growing compatible species are
tition between them and all ecological zones are exploited for acnieyo 5. From whe
yield. This method is called composite fish farming or polyculture of fishes. . Observe
Experiments have shown that indian major carps (i.e., Catla, tish.
exotic rohu
of carps (Le, and mrigal; Fig. 1.14) vhen S
ong with three ecies Silver carp, all 7. Visit a f
China), yield goes grass
from the carp and
species are transplalnted Based or
species are as follows: up -9 common carp, Fig
tmes,
habits of these six as compared to monO