Subject : Biology

Basic Terminology

Cell :- The basic structural & functional unit of life is called cell.

Tissue :- ‘A’ group of cells performing a particular function is called tissue.

Organ :- A group of tissue performing a particular function is called organ.

Organ System :- A group of organs performing a particular function is called organ system.

Eukaryotic cell :- The cell in which nucleus is well organized as well as member bound cell organelles are present is called Eukaryotic cell.

Prokaryotic Cell :- The cell in which nucleus is not well organized as well as membrane bound cell organelles are not present then it is called procariyotic cell.

Nutrition :- The process in which nutrients are taken inside the body is called nutrition.

NUTRITION Autotropric Hetrotroptric Photosynthesis Chemosynthesis Saprophytic Parasite Holozoid

Ectoparasite Ectoparasite

Autotrophic Nutrition (Self-dependent) :- The nutrition in which organisms depend on itself for nutrition is called autotrophic nutrition.

Chemosynthetic Nutrition :- The type of nutrition in which organisms prepare its own food in presence of chemical is called chemosynthetic Nutrition.

Photosynthetic Nutrition :- The type of nutrition in which organisms prepare its own food in presence of light is called photosynthetic nutrition.

Hetrotrophic Nutrition :- The nutrition in which organisms are depends on another organisms is called heterotrophic nutrition.

Saprophytic Nutrition :- The nutrition in which an organisms are dependent on the dead or decaying matter is called as saprophytic Nutrition.

Parasitic Nutrition :- The nutrition in which an organisms is dependent on another living organisms for is nutrition is called parasitic nutrition.

Endoparasite :- The parasite which is present outside the body of the host is called ectoparasite.

Holozoic Nutrition :- The nutrition in which organisms shows tendency towards engulfing food material is called holozoic nutrition.

HABITAT :

Aquatic organisms :- The organisms which can survive only in water are called as aquatic organizations.

Amphibian :- The organisms which can survive in water as well as on land are called amphibians.

Terrestrial :- The organisms which can survive in water as well as on land are called amphibians.

Arboreal :- The organisms which spends most of the life time over the trees are called arboreal organisms.

Aerial :- The organisms which can fly in air are called aerial originations.

Hydrophytes :- The plants which survives in water are called hydrophytes.

Mesophytes :- The plants which survives in moderate conditions are called mesophytes.

Xerophytes :- The plants which survives in high temperature and low rainfall in called as xerophytes.

Reproduction :- The process of production of new individual from the pre-existing individuals is called as Reproduction.

Types of Reproduction :

Haploid : A cell having single set of chromosomes is called Haploid. It is represented by ‘n’.

Diploid : A cell having two sets of chromosomes is called diploid (2n)

Gamete : A sexually reproducing cell is called gamete.

Sextual Reproduction : The reproduction in which hapliod male gamete unites with hapliod female gamete to form a diploid zygole is called as sexual reproduction.

Asexual Reproduction :- The reproduction which does not involve union of opposite haploid gamete is called Asexctual Reproduction.

Vegetative propogation / Reproduction : The formation of new plant from pre-existing plant body’s vegetative parts is called vegetative reproduction or vegetative propagation.

Vegetative Part : The part of the plant body which does not produces either male or female gamete is called vegetative part.

Reproductive part : The part which can produce either male or female gamete is called Reproductive part.

Cell Division : The ability of a cell to divide into two is called cell division.

Types of cell Division : A cell division can be differenciated into two types as

1) Mitosis. 2) Meiosis.

Mitosis :- A type of cell division in which a mother cell divide into two daughter cells is called mitosis.

Meiosis :- A type of cell division in which one mother cell divides into four daughter cells with the change in chromosome number is called meiosis.

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Subject : Biology. Topic : DIVERSITY IN ORGANISMS

1. DIVERSITY IN LIVING ORGANISMS :

Enormous variety of living organisms exist

on the earth. There are about 5-30 milion

species of plants and animals on earth. It is not

possible for a human being to remember the

characteristics of all these organisms without

their systematic arrangement.

2. SYSTEMATICS : TAXONOMY,

TAXONOMIC HIERARCHY AND BINOMIAL

NOMENCLATURE.

Systematics : “ Systematics is the scientific

study of similarities and differences among

different kinds of organisms and it also includes

their identification, nomenclature and

classification.

Taxonomy : It is the branch of biology which

deals with the collection, identification of plants

and animals.

Objectives of Systematics/ Taxonomy :

i) To know various kinds of plants on the

earth with their names, affinities,

geographical distribution, habit,

characteristics and their economic

importance.

ii) To have a reference system for all

organisms with which the scientists can

work.

iii) To demonstrate the manifold diversities

of organisms and their phylogenetic

(evolutionary) relationship.

iv) To ascertain nomenclature i.e, scientific

name for every organism.

Classification : The classification is based on similarities and

dissimilarities among the organisms.

Need of Classification :

i) The classification helps to explain

unity in diversity of the organisms.

ii) It is gives specific and scientific

names to the organisms which are

accepted universally.

iii) It reveals the relationships among

various group of organisms.

iv) The classification places an organism

amongst those which have common

characteristics.

Taxonomic hierarchy [Gr. – Hierarchs = rank]

The manner of scientific grouping of different

taxonomic categories in a descending order on

the basis of their ranks or positions in

classification is called taxonomic hierarchy.

i) Taxon :- Taxon a group of living organisms

(pl. taxa) which is used to represent a concrete

unit of classification.

ii) Category :- A category is a rank of level in

the hierarchial classification of organisms.

Example :

Method of classification of China rose and

Cobra.

Category Taxon Taxon

Kingdom Plantae Animalia

Division/Phylum Angiospermae Chordata

Class Dicotyledonae Reptilia

Sub-class Polypetalae Diapsida

Series Thalamiflorae -

Order Malvales Squamata

Family Malvaceae Elapidae

Genus Hibiscus Naja

Species Rosa-sinensis naja

Hierarchy of taxonomic categories :

Species : It is the basis unit in the system of

classification. Members of a species show all the

similar characters and are able to breed among

themselves to produce their own kind. For

Example, all the plants of potato (Solanum

tuberosum) are grouped under the species

tuberosum.

Genus : (Pl. genera) –

It is a group of closely related species.

E.g rosa- sinensis, esculentus, canabinus etc.

are different species under the genus

Hibiscus.

Family :

A family represents a group of closely

related genera.

The genera like Hibiscus, Malva, Sida,

Gossypium, Abutilon, etc. belong to the

family Malvaceae.

Order :

It is a group of closely related families which

resemble in major characters.

Families Malvaceae, Tiliaceae, Sterculiaceae

etc. belong to the order Malvales.

Sub-Class :-

It is an assemblage of different orders

having some similarities.

The orders, Malvales, Ranales, Parietales

etc. have free petals and hence grouped

under the sub-class Polypetalae.

Class :-

It is a group of related sub-classes.

The class Dicotyledonae includes sub-

classes as Polypetalae and Gamopetalae.

Division :

The division is a category composed of

related classes.

Division angiospermae includes two classes-Dicotyledonae and Monocotyledonae.

Sub Kingdom :

Different divisions having some

similarities from sub-kingdom.

Division Angiospermae and Gymnospermae

will form the sub kingdom Phanerogams or

Spermatophyta.

Kingdom :

It is the highest taxonomic category

composed of different sub Kingdoms.

Sub-Kingdom Phanerogams and

Cryptogams, form the Plant kingdom.

Binomial Nomenclature :

A system of nomenclature of plants and animals

in which the scientific name consists of two

words or parts or epithets is called binomial

nomenclature.

Rules of binomial nomenclature :

The name of the organism is composed of

two Latin or Latinised or Greek words.

The generic name is a simple noun should

come first and should begin with a small

letter.

These scientific names must be underlined

separately if hand written and must be

printed in italics.

The generic as well as specific name should

not have less than three letters and more than

thirteen letters.

Usually the name of the author, who names a

plant or animal, is also written in full or in

abbreviated form after the scientific name.

E.g. Mangifera indica L. where L. stands

for Linnaeus.

When a single species is described under

different names by different authors, then

these names are called synonyms. In such

cases the name under which the species is first

described is considered to be valid.

These names are simple, meaningful, precise

and standard as they are accepted universally

Due to this system confusion and uncertain

created by local or vernacular names is

avoided.

The binomials are easy to understand and

remember.

Indicate phylogeny (evolutionary history) of

organisms and help to understand

relationships between organisms, and groups

of organisms.

FIVE KINGDOM SYSTEM OF

CLASSIFICATION :

The five kingdoms are :

1. Kingdom Monera

2. Kingdom Protista

3. Kingdom Fungi

4. Kingdom Plantae

5. Kingdom Animalia

Kingdom : Monera

The organisms included in this kingdom are

microscopic and prokaryotic, having a

primitive type of nucleus.

The cells are without membrane bound cell

organelles

Composition :

The cell wall is rigid and composed of

peptidoglycan

Organisation :

These organisms are unicellular as in

eubacteria or filamentous as in cyanobacteria.

Locomotion :

These organisms are either motile (the

locomotion is due to gliding movement or

flagella. Cilia are absent or non-motile.

Nutrition :

The organisms exhibit different modes of

nutrition like autotrophic, heterotrophic,

parasitic or saprophytic. The autotrophs are

either photoautotrophs e.g. cyanobacteria or

chemoautotrophs e.g. Thiobacillus.

Reproduction :

The mode of reproduction in Monera is

either asexual or with the help of fission or

budding. (Sexual reproduction, mitosis and

meiosis are absent)

Example :

- Archaebacteria e.g. – Methanobacillus,

Thiobacillus, etc.

- Eubacteria. e.g – Rhizobium,

Clostridium

- Cyanobacteria e.g. – Nostoc,

Anabaena, etc.

- Actinomycetes e.g. – Streptomyces, Mycobacterium, etc.

Kingdom – Protista ( Protoctista) :

Occurrence :

These organisms are unicellular, eukaryotic

and mostly aquatic. However, some are

terrestrial.

They are either motile or non-motile. The

locomotory organs are cilia, flagella,

pseudopodia, etc.

Cell wall composition :

The protists are with or without cell wall. If

cell wall is present, it is composed of

cellulose.

Nutrition :

They show either photosynthetic, holozoic,

saprophytic or parasitic mode of nutrition.

The reserve food material is in the form of

glycogen or starch and fat.

Reproduction :

The reproduction is by asexual or sexual

method.

Asexual Reproduction :

Asexual reproduction occurs by mitotic or

amitotic cell division.

Sexual reproduction is by fusion of male

and female gametes forming zygote.

The zygote directly develops into young

individual without formation of embryo.

Plant like protists :

They are autotrophic (photosynthetic) have

cellulosic cell wall and store reserve food

as starch e.g. Dianoflagellates and Diatoms.

Animal like protists :

These are heterotrophic, ingest food, lack cell

wall and store reserve food as glycogen.e.g

Amoeba, Paramoecium.

Fungi like protists :

They are saprophytic and lack cell wall e.g.

Smile moulds.

Kingdom - Fungi :

It is a unique kingdom of heterotrophic

organisms, showing extracelluar digestion.

Organisation :

The organisms are unicellular of multicellular

and filamentous.

Unicellular Organisms :

They have a protoplast with many nuclei.

e.g. Rhizopus.

Multicelluar organisms consist of a body

called mycelium in which a number of

thread-like structures called hyphae are

present. The hyphae may be with septa

(septate) or without septa (aseptate). They

may be uni or multi-nucleated. The non-

septate multinucleated hyphae are called

coenocytic hyphae.

Cell wall Composition :

The cell wall in fungi is composed of chitin

or fungal cellulose.

Nutrition :

The fungi exhibit heterotrophic mode of

nutrition. Most of the members are

saprophytes.

Some are parasites or predators and some are

symbiotic

Reproduction :

Reproduction is vegetative, asexual of

sexual. (Example : Mucor, Rhizopus, Yeast,

Penicillum, Agaricus, ect.)

Kingdom : Plantae

The Kingdom Plantae includes multicellular,

eukaryotic and autrophic organism

Cell wall Composition :

The cell wall of plant cells is composed of

true cellulose.

Photosynthetic pigments :- The members

possess photosynthetic pigments.

Reserve food material :- It is in the form of

starch.

Vascular tissues :

Vascular tissues are absent in the lower

plants (Algae and Bryophytes) but present

in higher plants (Pteridophytes,

Gymnosperms and Angiosperms)

Reproduction :

The plants reproduce by vegetative, asexual

or sexual methods.

Vegetative reproduction : Vegetative

reproduction occurs with the help of

vegetative parts.

Asexual reproduction : Asexual

reproduction with the help of spores.

Sexual reproduction: Sexual reproduction

takes place with the help of gametes.

Example :

- Algae e.g. - Spirogyra, Chara, etc.

- Bryophytes e.g. - Riccia, Funaria, etc.

- Pteridophytes e.g - Lycopodium, Nephrolepis,

etc.

- Gymnosperms e.g.- Cycas, Pinus, etc.

- Angiosperms e.g. – Sunflower, Jowar, etc.

Kingdom Animalia :

Occurance : The animals are multicellular

and eukaryotic and may be aquatic,

terrestrial, amphibious or aerial.

Locomotion : Majority of the animals are

motile. However a few like sponges are

sedentary.

Cell Wall Composition : The animals cells

do not possess cell wall, plastids and central

vacuole.

Nutrition : They are heterotrophic, mostly

holozoic and some are parasitic.

Advantages of S. Kingodom System :

The fungi are separated from Plantae on the

basis of their saprophytic mode of nutrition.

Organisms with doubtful placement like

Euglena get proper place in classification.

During redistribution of the organisms

among additional kingdom, the original sub-

divisions of old two-kingdom system are not

disturbed.

Drawbacks in five kingdom system. :

Viruses do not find any place in five-

kingdom dystem of classification.

Kingdom Protista includes photosynthetic

and non-photosynthetic organisms, as well

as those with or without cell wall and it is

difficult to imagine them together.

LICHENS : The lichens are slow growing, long

living organisms, occurring in wide variety of

places.

Composition : Lichens are formed by close

association of two different partners (organisms)

one of which is an algal component and the other

is fungal component. The algal component is

called phycobiont or photobiont and it mostly

belongs to Chlorophyceae (green algae) or

cyanobacteria (blue green algae). The fungal

component is called mycobiont and it mostly

belongs to Ascomycetes and rarely

Basidiomycetes or Deuteromycetes.

Habitat :

The Lichens are distributed in wide variety of

habitats. They grow on tree trunks, decaying

logs, and on soil too.

They are sensitive to air pollution and

generally do not grow near the cities.

They are thalloid, and the thallus is greenish or

bluish green in colour. Some lichens have

additional pigments such as yellow, orange,

brown and black.

Body structure :

On the basis of fungal components the lichens

are divided into three cagagories.

Type of lichens :

A) Ascolichens - In this category the fungal

partner belong to Ascomycetes.

B) Basidiolichens - Here the fungal partner

belongs to Basidiomycetes.

C) Deuterolichens – In this category the fungal

partner belongs to Deuteromycetes. These

are sterile lichens producing no spores.

On the basis of external form, (thallus

organization) the lichens are of three types

as-

A) Crustose Lichens - These are thin and flat

lichens occurring as crust on the bark or rock.

e.g. Graphis. Leanora, Haematomma etc.

B) Foliose Lichens - These are lobed and

dorsiventrally flattened, leafy lichens. They are

attached to substratum by hairy rhizoid like

structures called rhizines e.g. Parmelia, Collema,

Petligera.

C) Fruticose Lichens - These lichens are

commonly called shruby lichens. They have

cylindrical, branched and erect or pendulous

thallus which given them a shrub like

appearance. They remain attached to the

substratum by basal mucilaginous disc. e.g.

Cladonia, Usnea, Alectoria.

The lichens generally reproduce by vegetative,

asexual and sexual methods.

Economic Importance of Lichens.

1) Lichens as Food :-- Several lichens are

used as food. The lichens contain as substance

lichenin which is similar to carbohydrate e.g.

Lecanora esculenta in Israel and Umbilicaria

esculenta in Japan. Parmelia is used in curry

powder as well as in making chocolates and

pestries.

2) Lichens as Fodder :-- Lichens form a

favourite food for reindeers and cattles. Species

of Cladonia, Citraia, Evernia, Parmelia are

used as fodder.

3) Medicinal Uses :-- Usnic Acid obtained

from the Usnea and Cladonia species is used as

an antibiotic against Gram positive bacteria,

Lobaria, Citraria species are, useful in

respiratory disease like T. B., Peltigera is useful

in hydrophobia, Parmelia is useful in epilepsy

and Usnea species in urinary disease. Some

lichens possess anticarcinogenic property.

4) Industrial Uses of Lichens :--

a) In Sweden na Russia, Lichens are used

for production of alcohol.

b) Lichens are used in the process of

tanning and dying.

c) In the litmus paper preparation which

used as acid-base indicator extract of

species of Rocella and Lasallia are used

d) Orcein a biological stain is obtained

from orchrolechia androgyna and O.

tortaria.

e) In Perfumery, species of Evernia and

Ramalina are the sources of essential

oils which are used in preparation of

soaps and other cosmetics.

Ecological Importance of Lichens : The

lichens are the pioneers of vegetation on rocks.

Lichens are the first plants to settle on barren

rocks. Lichens bring about weathering of rocks

by releasing carbonic and oxalic acids.

Weathering of rocks leads to formation of soil

and is called pedogenesis.

VIRUSES AND VIROIDS :

Viruses : Viruses are a cellular, highly

infectious microorganisms which are considered

to be on the threshold of life.

Size : Their size ranges from 10nm to 2000nm

Viruses do not grow, do not eat food or

respire.

Body Structure :

Viruses show very simple structure i.e. a

nucleic acid core surrounded by a protein

coat (capsid) to form the nucleocapsid.

They posses their own genetic material in

the form of either DNA or RNA (but never

both).

They can be crystallized.

They can be stored for long period.

Reproduction :

They utilize the ribosomes and enzymes of

the host cell for synthesis of protein during

reproduction

Types of viruses : (Classification of viruses)

Viruses are classified into three groups on

the basis of their hosts.

1) Plant viruses :- The viruses which attack

and infect plants are called plant viruses.

These viruses consists of ss.-RNA or

ds-RNA. They show helical symmetry and

are mostly rod-shaped or cylindrical.

(e.g. : TMV)

2) Animal viruses :- The viruses which attack

and infect animals are called animal viruses.

The genetic material is either RNA or DNA.

They show radial symmetry. These are

mostly polyhedral in shape.

(e.g. : Herpes)

3) Bacterial viruses or Bacteriophages :- (Greek phagin=eater). The viruses which

attack and infect the bacteria are called

bacteriophages or bacterial viruses. The

genetic matrial is DNA. They were

discovered by Twort (1915). Felix d’ Herelle

named them as bacteriophages. They are

mostly tadpole shaped.

Economic Importance of viruses :

The plant viruses and animal virues are of great

economic importance as they cause various

diseases in plants and animals.

Plant diseases caused by viruses are like –

1) Little leaf of Brinjal

2) Yellow vein mosaic of lady’s finger.

3) Potato leaf roll

4) Leaf curl of papaya

5) Bunchy top of banana

6) Grassy shoot of sugarcane

7) Tabacco mosaic disease

Common symptoms due to viral infection

include –

Local lesions clearing of veins, mosaic

formation, chlorosis, necrosis, stunting and

premature defoliation, ring spotting, etc.

Animal diseases caused by viruses are like.

Disease virus

1) Common cold - Rhino virus

2) Influenza - Orthomyxo viruses

3) Small pox - Variola virus

4) Mumps - Myxovirus parotiditis

5) Mealses - Morbilli virus

6) Poliomyelitis - Polio viruses

7) Yellow fever - Flavi virus

8) Swine flu - H1N1 virus

9) AIDS - Retro virus /HIV

Viroids :

These are very small, circular, single –

stranded RNAs which are not complexed with

any protein. (without protein coat) This RNA is

either covalently closed circular RNA or single

stranded linear RNA. These are mainly plant

pathogens.

The first viroid discovered was the potato

spindle tuber viroid (PSTV) which causes a

disease in potato. PSTV is composed of 359

nucleotides and thus has ten times less genetic

material than the smallest known virus. The

naked RNA molecule can replicate

autonomously in plant cells. It can also disperse

into the environment and produce disease.

*******************

Subject : Biology. Topic : KINGDOM PLANTAE

INTRODUCTION : On the earth there is a

large number of living organisms, conmmonly

known as plants, animals and microorganisms.

All multicellular, eukaryotic organisms with

photosynthetic mode of nutrition are included

under kingdom Plantae. These are the main

producers on land and in water. With the help of

green pigments (chlorophylls) they synthesize

carbohydrates and release oxygen in air. Thus

they are the most essential biotic components of

the ecosystem.

Kingdom plantae is broadly classified into

two sub-kingdoms.

A) Cryptogamae B) Phanerogamae

Cryptogamae :-

Cryptogams are spore producing plants,

and do not produce seeds and flowers.

They reproduce sexually by gametes but

sex organs are concealed.

Cryptogams include three major groups,

namely (a) Algae (b) Bryophytes (c)

Pteridophytes.

Habitate : Algae are mostly aquatic, some

being terrestrial also. A few alage grow on

other plants. Aquatic algae grow in marine

water or fresh water. Most of them are free

living while some are symbiotic.

Structure : The vegetative structure (thallus)

of algae display variety in organization and size.

Theymay be small, unicellular, microscopic like

chlorella (non-motile), chlamydomonas (motile)

or multicellular unbranched filamentous like

Spirogyra, or branched filamentous like Chara

or huge macroscopic such as sea weeds which

measure more than 60 meters in length e.g.

Sargassum.

Cell Composition :

The algal cell wall consists of two layers i.e.

inner cellulosic and outer composed of

pectin.

The algae consist of various type of

photosynthetic pigments. Chlorophyll-a

(essential pigment) is present in all groups of

algae. The accessory pigments present are

chlorophyll-b, chlorophyll-c and chlorophyll-

d, carotenes, xanthophylls and phycobilins.

Phycobilins are of two types i.e, phycocyanins

and phycoerythrins.

The reserve food material is in the form of

starch, laminarin-starch, mannitol or

floridean-starch, etc.

Reproduction :

Algae reproduce by three different methods.

Vegetative reproduction occurs by

fragmentation (in filamentous forms) and cell

division (in inicellular forms.

Asexual reproduction occurs by the formation

of various types of non- motile or motile

spores.

Sexual reproduction takes place by formation

and fusion of gametes.

Occurrence :

The bryophytes are mostly terrestrial plants

which depend of external water for

fertilization and completion of their life cycle.

Hence they are called amphibian plants.

Habitat :

The Bryophytes generally grow in shady and

moist places such as moist walls, damp rocks,

moist soil and on decaying logs.

Body Structure :

They show thalloid plant body which is not

differentiated into root, stem and leaves as in

liverworts. In mosses, thallus is foliose, i.e, it

bears leaf-like structures.

Rhizoids :

In Bryophytes true roots are absent but

rhizoids are present. Rhizoids are unicellular

in liverworts while multicelluar in mosses.

They absorb water and minerals and also help

in fixation of thallus to the substratum.

Vascular tissues :

The vascular tissue are absent. However, a

condicting strand of ew thick-walled cells is

present in mosses.

Leaves :

Some bryophytes show leaf like structures

(e.g. moss) but they are not true leaves. They

do not produce flowers or seeds as well.

Bryophytes show heteromorphic alternation

of generations. In which the gametophyte is

the dominant, green haploid and independent

phase while sporophyte is diploid recessive

and partially dependent on gametophyte.

Reproduction :

Bryophytes reproduce by vegetative means i.e,

by special structures like tubers and gemmae

while asexual reproduction takes place by spore

formation Sexual reproduction occurs by

formation of gametes.

Examples :

Liverworts e.g. - Raccia ; Marchantia

Hornworts e.g. - Anthoceros

Mosses e.g. - Funaria.

Division : Pteridophyta (pteron – feather :

phyton = plant) :-

The pterodophytes were the first vascular

plants on the land and are hence considered

as the first successful terrestrial plants.

The Pteridohytes are also known s vascular

cryptogams.

Habitat :-

The Pteridophytes are terrestrial, small,

either annual or perennial, and grow

luxuriantly in moist and shady places. e.g.

ferns. They may be aquatic (Azolla,

Marsilea), xerophytic (Equisetum) epiphytic

(Lycopodium) i.e. growing on large trunks

of trees.

Alo

The pteridophytes show heteromorphic

alternation of generation in which the

sporophyte is diploid, dominant,

autotrophic, independent and is

differentiated into root, stem and leaves.

Root Structure :-

The primary root is short-lived and is soon

replaced by adventitious roots while the

Leaves :-

The leaves may be scaly (Equisetim), simple

and sessile (Lycopodium) or large and

pinnately compound (Ferns).

Vascular tissue. :-

In pteridophytes the xylem consists of only

tracheids and phloem consists of sieve cells

only. Secondary growth is not seen in

Pteridophytes due to absence of cambium.

Reproduction. :-

The sporophyte shows asexual reproduction

and produces spores by meiosis from which

the gametophyte develops. Gametophyte is

haploid recessive but independent, and

reproduces sexually. Product of sexual

reproduction, i.e. zygote produces diploid

sporophyte.

Apogamy - It is the development of the

sporophyte without the fusion of the male

and female gametes. It arises directly from

the gametophyte. Here the sporophyte is

haploid.

Apogamy - It is the development of

thegametophyte from any cell of the

sporophyte other than the spores. Such a

gametophyte is diploid in nature.

Phanerogamae - The members of

Phanerogamae i.e, Phanerogams are

commonly called seed plants. Which are

further divided into two divisions name

a) Gymnospermae b) Angiospermae.

Gymnospermae :-

Gymnosperms are the plants with naked

seeds.

Most of the Gymnosperms are evergreen,

perennial woody trees or shrubs.

Vascular Tissue :-

They are vascular plants having xylem

with tracheids and phloem with sieve cells.

The Gymnosperms show heteromorphic

alternation of generations. The sporophyte

is diploid, dominant, autotrophic,

independent while the gametophyte is

haploid, recessive and dependent. (It is

much reduced and exists within

sporophyte.)

stem may be aerial or underground.

Vascular Tissue :-

They are vascular plants having xylem

with tracheids and phloem with sieve

cells.

The Gymnosperms show heteromorphic

alternation of generations. The

sporophyte is diploid, dominant,

autotrophic, independent while the

gametophyte is haploid, recessive and

dependent. (It is much reduced and

exists within sporophyte. )

Morphology :-

The plant body i.e. sporophyte is

differentiated into root, stem and leaves.

The root system is well developed tap

root system. Coralloid roots of Cycas

show association with blue-green algae

roots of Pinus show association with

endophytic fungi called mycorrhizae.

Stem :-

The gymnospermic stem is mostly erect,

aerial, solid and cylindrical. In cycas it

is usually unbranched, while in conifers

it is branched.

The leaves are dimorphic. The foliage

leaves are green, simple, needle like or

pinnately compound, where as scale

leaves are small, membranous and

brown.

Secondary growth is seen in

Gymnosperms due to presence of

cambiu.

Type of Spores :-

Gymnosperms are heterosporous. They

produce microspores (pollen grains) in

mocrosporangia and megaspores in

megasporangia (ovules). The sporangia

are borne on leafy structures called

sporophylls which are often aggregated

to form cones or strobili (sing-strobilus).

Reproduction :-

The pollination in Gymnosperm is

anemophilous (wind pollination) and direct

as the pollen grains are received directly in

the pollen chamber of the ovule.

Fertilization is achieved through a pollen

tube. This process is called siphonogamy.

Vegetative reproduction takes place with the

help of bulbils.

Some Gymnosperms like Ginkgo biloba are

called living follils. It is because the plant is

found in living as well as follil form, and the

number of fossil forms is much more thena

the living forms.

ANGIOSPERMS :-

The Angiospermae is the most advanced

division of the flowering plants. The

Angiosperms are flowering plants in which

seeds are enclosed within the fruit.

Habitat : -

The Angiosperms is a group of highly

evolved plants, primarily adapted to

terrestrial habitat.

They vary in size; e.g. Wolffia is the smallest

angiosperm, 1mm in size and Eucalyptus

grows to over 100 meters.

Marphology :-

The plant body is differentiated into root,

stem and leaves. It has flowers, fruits and

seeds.

Vascular tissue are well developed. Xylem

shows vessels or tracheae while phloem has

sieve tubes and companion cells.

Angiosperms show heteromorphic

alternation of generation in which the

sporophyte is diploid, dominant, autotrophic

and independent while the gametophytes

(male or female) are recessive, haploid and

delepndent on the sporophyte. (exist within

sporophyte)

Reproduction Asexual reproduction :-

Angosperms are heterosporous. Microspores

(commonly called pollens) are formed in

microsporangia. They develolop in highly

specialized microsporophylls or stamens while

megaspores are formed in megasporangia (or

ovules) borne on highly specialized

megasporophylls called carpels.

Pollination :- In Angiosperms the pollination is

indirect (pollen grains received on stigma) and

may be self or cross.

Sexual Reproduction :- These plants show

double fertilization. One male gamete fuses with

egg cell and another fuses with secondary

nucleus, to form embryo and endosperm

respectively. It occurs within the ovule, and

ovule changes to seed. The ovqer simultaneously

ripens into a fruit.

Class dictyledonae :-

These plants have two cotyledons in their

embryo.

They have a tap root system and the stem is

generally profusely branched.

The leaves show reticulate venation while

the flowers show tetra or pendamerous

symmetry.

The vascular bundles are conjoint, collateral

and open. In dicots secondary growth is

commonly found.

Class Monocotyledonae :-

These plants have single cotyledon in their

embryo.

They have adventitious root system and the

stem is rarely branched.

The leaves generally have sheathing left

base and parallel venation while the flowers

are generally trimerous.

The vascular bundles are conjoint, collateral

and closed. In monocots, secondary growth

is absent due to absence of cambium. (e.g.

Zea mays (Maize) Sorghum vulgare. Jowar)

Importance of Botanical Garderns :-

Botanical garders are important for

They records of local flora and as basis for

continued monographic work.

That provide vacilities for collection of

living plant material for studies.

Botanical gardens also supply seeds and

material for botanical investigations.

The botanical gardens in addition to

outdoor garden, may contain herbaria,

green houses, research laboratory and

library.

Botanical Gardens of India :

1) The Indian Botanical Gardern, Kolkata.

2) Lioyd Botanical Garden, Darheeling.

3) National botanical Garden, Lucknow.

4) Botanical Garden of the Forest Research

Institute, Dehradun.

5) Government Botanical Garden,

Ootacamund.

6) The State Botanical Garden, Lalbagh,

Mysore.

7) Botanical Garden, Saharanpur.

Herbaria :-

The collection or deposition of dried plant

material by using various techniques of

preservation and their arrangement in the

sequence of an accepted classification, forms

herbaria.

A herbarium technique involves collection,

drying, poisoning, mounting, stitchning,

labeling and deposition.

Herbaria are associated with research

institutes, scientific societies, botanic

gardens, universities and colleges.

Herbaria can be classified into three main

categories such as –

a) Regional herbaria

b) Local herbaria and

c) Herbaria of educational institutions

including schools, colleges and

universities.

Importance of herbaria :-

The hyrbaria preserve national regional,

local plant wealth.

Help to carry out research programmes of

fundamental or of applied value.

It also facilitates exchange and loan of

preserved plant material for various

purpose like exhibitions, research etc.

It fulfils public demand by supplying plant

material and giving scientific information

regarding plants by arranging training

courses.

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Metaphase :

During metaphase, the condensation of chromosomes is completed and the thick

chromosomes get organized along equational plane of the cell.

This phase is characterized by formation of kinetic spindle.

In animal cells the spindle fibres radiate as an aster from centriole and called astral rays.

Hence it is called astral mitosis.

In plant cells asters are absent and so it is called anastral mitosis.

Anaphase :

Centromeres divide into two, resulting in the separation of chromatids. Each separated

chromatid is now called daughter chromosome

The kinetic spindle now has four type of fibres made up of microtubules. They are

4) Telephase :

At the poles, daughter chromosomes uncoil and undergo hydration to from chromatin network.

The nuclear membrane begins to reappear around each group of aughter chromosomes and the

daughter nuclei are formed.

Cytokinesis :

The division of cytoplasm of the mother cell is called cytokinesis.

In animal cells it occurs by furrowing of plasma membrane that deepens and the daughter cells

ar formed. This process is called cleavage. In plant cells it takes place formation and extension

of cell plate, from centre to the periphery.

MEIOSIS :

Meiosis is a type of cell division, which involves halving of the chromosome number.

Therefore, it is termed as reduction division.

The meiotic division involves two successive divisions.

a) Meiosis-I or reduction division

b) Meiosis-II or equational division both of which have karyokinesis and cytokinesis

phase. Karyokinesis includes four phase like mitosis.

A) Meiosis – I or reduction division :

Interphase :

It is similar to that in mitosis.

Karyokinesis :

a) Prophase-I : It is furthet distinguished into five sub-stage viz, leptotene

i) Leptotene or leptonema , ii) Zygotene or Zygonema, iii) Pachytene or

Pachynema, iv) Diplotene, v) Diakinesis,

i) Leptotene or leptonema : During this phase the chromatin network condenses and

resolves into long and thin, thread like chromosomes.

ii) Zygotene or Zygonema : It is a phase in which homologous chromosomes begin to pair

lengthwise . Such a pairing of chromosomes is called synapsis.

iii) Pachytene or Pachynema :

During this phase condensation of chrosomes progresses and they become short

and thick.

During this process crossing over i.e, exchange of genetic material between non-

sister chromatids of homolgous chromosomes takes place.

It result in genetic recombination of parental characters.

The points where crossing over takes place are called chiasmata.

iv) Diplotene : The homologues now start repelling each other and begin to separate.

However, at the points of crossing over, they remain attached and thus chiasmata can be

seen. Nucleolus and nuclear membrane start disappearing.

v) Diakinesis :

During this phase chromosomes continue to condense and shorten.

The chrasmata get shifted to the ends of chromatids called terminalisation.

The nucleolus and nuclear membrane completely disappear and kinetic spindle

become apparent.

b) Metaphase – I

The spindle formation is complete and the bivalents move and arrange themselves at the

equatorial plane.

c) Anaphase – The chromosomal fibres contract and pull the homologues and

inter-chromosomal fibres appear and extend so that homologous chromosomes start moving

towards opposite poles.

A) Telophase-I : The chromosomes uncoil to form chromatin. The spindle fibres

disappear. The nuclear membrane and nucleolus reappear forming two daughter nuclei.

Cytokinesis – I

Telophase-I is often followed by division of the cytoplasm.

B) Meiosis – II : a) Prophase – II : During this phase the chromosomes with chromatids become

distinct. The nucleoius and nuclear membrane disappear.

b) Metaphase – II : During this phase spindle formation takes place and the

chromosomes move towards equatorial plane. The chromosomes get connected to the

respective poles by the chromosomal fibres.

c) Anaphase II : The centromere of each chromosome divides and chromatids are

separated. Each chromatid is now called daughter chromosome.

Telophase II : The daughter chromosomes which have gathered at each pole start

uncoiling . The nucleolus reappears and the nuclear membrane is formed around each

group of chromosomes forming two daughter nuclei.

Cytokinesis-II

Telephose-II is followed by division of cytoplasm of each cell forming two

daughter cells. At the end of meiosis-II four haploid daughter cells are thus formed.

Subject : Biology

Biochemistry of cell

Introduction :

Cell is a fundamental, structural and functional unit of an organism.

One of the major attributes of a living cell is its ability to carry of metabolic activities. To know how a tiny cell

can carry out the metabolic activities one has to understand the chemistry of various organic molecules, found

in cells. The collection of various types of molecules in a cell is known as cellular pool.

Metabolism, it indicates a variety of reactions carried out at cellular level. The metabolic reactions can be

divided into two main categories such as

i) Anabolic reactions- The reactions in which biosynthesis of a new cellular material takes place.

ii) Catabolic reactions- The reactions in which a complex storage product is hydrolyzed and or broken

down into smaller and simpler molecules.

Both, anabolic and catabolic reactions catalyzed by biological catalysts called enzymes.

BASIC CHEMICAL CONSTITUENTS OF CELL: Carbohydrates: Carbohydrates are the basic components food.

Carbohydrates are compounds of carbon, hydrogen and oxygen atoms.

The general formula is C H O for simple (C H O)n, for complex carbohydrates.

Rhamnose (C H O) and digitoxose (C H O) are carbohydrates, but do not follow general formula of

carbohydrates. Simple carbohydrates are commonly known as sugars.

Complex carbohydrates like starch, cellulose, etc.

Carbohydrate molecules are also characterized by the presence of either aldehyde (-CHO) or ketone (C=O)

group and two or more hydroxyl (-OH) groups.

Classification of carbohydrates

The three types are-

1) Monosaccharides

2) Disaccharides and

3) Polysaccharides

1) Monosaccharides:- Monosaccharides are compounds, which cannot be further hydrolyzed into still

smaller molecules.

Monosaccharides are further classified aldoses and ketoses

They consist of 3 to 6 carbon atoms. They are crystalline, soluble in water and sweet to taste.

On the basis of number of carbon atoms

the monosaccharides can be trioses, tetroses,pentoses, hexoses etc.

2) Desaccharides: Disaccharide is a carbohydrate made up of two monosaccharide units.

These are soluble in water, sweet to taste and crystalline. The covalent bond that joins monosaccharide

units is called glycosidic bond.

The most familiar disaccharides are sucrose, lactose, maltose.

3) Polysaccharides: These are complex carbohydrates formed by the condensation of large number of

monosaccharides. A single polysacchyaride may consist of thousands of units of monosaccharide may.

These are amorphous, tasteless and insoluble in water. A polysaccharide may contain one type of

monosaccharides (or homopolysaccharide) or different types of monosaccharides

(heteropolysaccharide).

The role of carbohydrates is (1) To provide energy for metabolism. (2) The monosaccharide like

glucose is main substrate for synthesis of ATP. (3) In mammals, disaccyharide lactose present in the

milk, provides energy to their babies. (4) The polysaccharedes serve as structural components of cell

membrane and cell wall and also serve as reserved food material (starch).

Proteins are long chain polymers of amino acids.

Serve as an important structural constituent of cells. Most of the proteins are host species and show

slight variations in each species. The differences among the species are due to differences in their

protein components.

All proteins consist of nitrogen in addition to the carbon, hydrogen and oxygen. Some protein

molecules contain sulphur and other elements in addition to C, H, O, and N.

In a long chain of amino acids forming a protein, the amino group (-NH) of one amino acid is linked to

the carboxyl (-COOH) group of the other amino acid. Two amino acids are condensed by removal of a

water molecule (OH from COOH and H from NH) to form a peptide linkage. The remainder of each

amino acid after removal of a water molecule (H+ and OH-) is called residue. A molecule of a protein

made up of two amino acid residues is called dipeptide, of three residues as residues as tripeptide and

of many residues as polypeptide.

Classification of proteins:

1) Simple proteins: These are composed of only amino acids or their derivatives. e.g. histones, zein

from maize.

2) Conjugated proteins: These are simple proteins (amino acids) with some non protein part called

prosthetic group.

Proteins play important role as –

Enzymes- Most of the enzymes are proteins ( all proteins are not enzymes) e.g. amylase.

Hormones- Hormones like insulin, growth hormones, etc. are proteins.

Structural Proteins- These proteins form parts of cells or tissues

Contractile proteins- These proteins occur in muscles. e.g.

Transport proteins- They are useful for transportation of certain materials e.g.

Defensive Proteins- They are useful for protection of the body against diseases. e.g.

Lipids:

Lipids are a group of organic components having oily or greasy consistency.

Lipids are a group of heterogenous compounds like fats, oils, steroids, waxes etc.

Lipids are insoluble in water but freely soluble in organic or non-polar solvents benzene, chloroform,

etc.

Similar to carbohydrates lipids are composed of C, H, O atoms

Compound lipids contain N, S and P in addition to C, H and O.

Classification of lipids:

Lipids are classified into 3 main types as-

1) Simple lipids

2) Compound lipids

3) Derived lipids

1) Simple lipids: These are esters of fatty acids with alcohol, Glycerol is a three-carbon alcohol with three

–OH groups. Fatty acid is a long straight chain of carbon atoms with a carboxyl (-COOH) group at one

end.

Saturated fatty acids - These fatty acids do not have double bond between carbon atoms of its chain

e.g. palmitic acid, stearic acid, etc.

Unsaturated fatty acids – These fatty acids contain one or more double bonds between carbon atoms of

its chain e.g. oleic acid, linoleic acid,

Fats containing unsaturated fatty acids liquid at room temperature and are called oils.

2) Compound lipids: These lipids contain some additional elements or groups in addition to fatty acids

and alcohol such as nitrogen, phosphorous, sulphur, protein, etc.

3) Derived lipids: These lipids are the hydrolytic products of lipids. They include – Steroids, waxes,

carotenoids, essential oils, etc.

a. Steroids: Steroids are structurally quite different from other lipids. Each molecule of steroid has

carbon atom arranged in four interlocking rings. Some of the biologically important steroids are

cholesterol, bile salts, male and female sex hormones

b. Waxes: Plant waxes are esters of saturated fatty acids with long chain alcohols and ketone. These

are secreted by epidermis and form a covering on stem, fruits and leaves. In animals, fur and feathers

are wax.

c. Carotenoids: Carotenoids are pigments composed of two, six-carbon rings with a highly

unsaturated strait chain of hydrocarbons.

For example, alpha and beta carotene, xanthophylls, etc.

Role of lipids :

1) Lipids act as high energy reserve food material e.g. oil seeds store oils.

2) They are important components of cell membrane of eukaryotes e.g.

3) Some of the lipids act as components of some enzyme systems.

4) Subcutaneous tissue contains fat which acts as insulator for heat.

5) Wax provides water proofing and checks the rate of transpiration in plants.

6) Steroids like cholic acid are constituents of bile.

7) Cholesterol takes part in the synthesis of vitamin D and is precursor molecule of many sex

hormones.

From the chemical analysis of nucleus it is clear that it consists of two types of nucleic acids i.e. DNA

(Deoxyribose nucleic acid) and RNA

Nucleic acids are macromolecules composed of many small units or monomers called nucleotides.

Each nucleotide is formed of three components i.e. a pentose (5c) sugar, a nitrogenous base and a phosphate

(phosphoric acid).

I) Sugar - It is a pentose (5c) sugar. The sugars can be one of the two types i.e. ribose sugar or

deoxyribose sugar. II) Nitrogenous bases – Each nucleotide has one of the four types of nitrogenous bases out of which

two are purines and remaining two are pyrimidines. Purine bases are double ring compounds

further distinguished into adenine and guanine while pyrimidine bases are single ring compounds

further distinguished into thymine, cytosine and uracil.

III) Phosphoric acid – Phosphate is present in nucleic acid (H PO)

DNA is double-stranded helix in which each strand is made up of thousands of deoxyribose

nucleotides.

The two strands of DNA molecule are antiparallel, complementary and are joined by weak H-

bonds.

There are two –H bonds between adenine and thymine while three-H bonds between guanine and

cytosine. Total the number of purine bases is equal to that of purimidine bases. Thus purine:

pyrimidine ratio is 1:1.

In eukaryotic cell DNA is found mainly in mitochondria and chloroplasts. It is the genetic material

and contains all the information needed for development and existence of an organism.

Structure of Ribose Nucleic Acid (RNA)

RNA is single stranded and the strand may be straight or variously folded upon itself. The

nitrogenous -base thymine is replaced by uracil in RNA.

1) Genetic RNA : RNA is the genetic material in most of the plant viruses and some animal

viruses.

2) Non-genetic RNA: This type of RNA is present in organisms in which the genetic material is

DNA.

I) m-RNA (Messenger RNA):

(1) It is a linear moteaule. Its synthesis takes place on DNA by the process called

‘Transcription’.

(2) It carries genetic information from nucleus to the site of protein synthesis.

(3) It forms about 5% of the total cell RNA.

II) r-RNA (Ribosomal RNA):

(1) It is a linear molecule folded at certain regions due to complementation of nitrogenous bases.

(2) It is associated with ribosome.

(3) It forms about 80% of the total cell RNA.

III) t-RNA (Transfer RNA) :

(1) It is soluble RNA with hair pin or clover leaf like structure.

(2) This is the smallest among three types.

(3) It forms about 10-15% of the total cell RNA.

(4) It carries activated amino acids to ribosomes and helps in elongation of polypeptide chain

during the process of translation.

Enzymes:

In livings cells the reactions occur at normal body temperature and pressure due to the

presence of specialized macromolecular, proteinaceous substances called enzymes.

The enzymes that are produced within a cell for metabolic activities are known

endoenzymes those which act away from the site of synthesis are called exo-enzymes.

General properties of enzymes and factors affecting enzyme activity.

1) Enzymes accelerate the reaction but do not initiate it.

2) Enzymes themselves do not participate in the reaction and remain unchanged at the end

reaction.

3) The molecule of an enzyme is larger than that of substrate molecule and hence during

reaction a specific part of enzyme molecule comes in contact with the substrate molecule.

That part is called active site of enzyme.

4) Amphoteric nature: Chemically most of the enzymes are proteins and, therefore, show

amphoteric nature.

5) Specificity: Most of the enzymes are specific in their action.

6) Colloidal nature: All enzymes are colloidal in nature and thus provide large surface area

for reaction to take place.

7) Enzyme optima: Enzymes generally work best under certain narrowly defined conditions

referred to as optima.

8) Concentration of enzyme and substrate

The rate of reaction is proportionate to the concentration of the reacting molecules.

9) Enzyme inhibitors- Enzyme inhibitors are certain products which inhibit enzyme activity.

Some important Diagrams