CONCEPT FIVE KINGDOM CLASSIFICATION

MAP
The scientific procedure of arranging organisms into groups and subgroups on the basis of their similarities and dissimilarities and placing them in a
hierarchy of categories is called biological classification. The earliest classification systems recognised only two kingdoms of living things: Animalia and
Plantae followed by three and four kingdom classifications introducing Kingdom Monera and Protista. The most accepted and latest five-kingdom
classification was proposed by R.H. Whittaker in 1969 to develop phylogenetic relationships. In this classification, the organisms are classified on the basis
of following criteria : (i) complexity of cell, (ii) complexity of the body organisation, (iii) mode of nutrition, (iv) mode of reproduction, (v) ecological role and
(vi) phylogenetic relationships.

Classification Criteria
Major
Producer Decomposer Consumer
Ecological Role

Mode
Autotrophy (Photosynthesis) Heterotrophy (Absorption) Heterotrophy (Ingestion)
of Nutrition

KINGDOM FUNGI
KINGDOM ANIMALIA
l It contains achlorophyllous,
l It has maximum number and most
KINGDOM PLANTAE spore producing, multicellular or
diverse types of organisms.
multinucleate eukaryotic organisms.
l It contains all photosyn- l Organisms are multicellular eukaryotes. Body
l They have heterotrophic with absorptive
thetic eukaryotic multicellular form is regular. Cellular, tissue and organ system
type of nutrition i.e., either saprobic or parasitic.
plants and their non-photosynthetic levels of organisation occurs in different groups. A
l Cell wall contains chitin and noncellulosic
cell wall is absent. The organisms have holozoic or

m
relatives. polysaccharides. The cellular organisation is two
l Mode of nutrition is mainly autotrophic, ingestive type of nutrition. A few animals are,
envelope type.
hence called producers. Some of the plants are however, parasitic. They live on or inside the bodies

a
l Reproduction is both asexual and sexual.
heterotrophic, of which most are parasitic and a of other eukaryotes.
Basidiomycota l Reproduction is mostly sexual.

gr
few are saprobes.
l Cell wall is cellulosic. Food reserve is usually starch (Club fungi)
and fat. Chordata

le
l Reproduction is both asexual and sexual. (Chordates)

Te
Angiospermae Echinodermata
Phaeophyta Ascomycota (Echinoderms)
(Brown algae) (Sac fungi)
Tracheophyta

Mollusca
Deuteromycota (Molluscs)
on
(Fungi imperfecti)
Gymnospermae
Arthropoda
(Arthropods)
e

Zygomycota Annelida
Pteridophyta
s

(Conjugation fungi) Nemathelminthes (Segmented worms)

(Roundworms)
do

Bryophyta Platyhelminthes
Oomycota Cnidaria
(Mosses and (Flatworms)
(Water molds) (Coelenterates)
liverworts) Porifera
ly

(Sponges)
Rhodophyta
Myxomycota
ai

Chlorophyta (Red algae)

(Slime molds)
Multicellular (Green algae)
D

Euglenophyta KINGDOM PROTISTA

Unicellular
Ka

(Euglenoids) l It includes all unicellular and

colonial eukaryotes. Most of them are
Complexity aquatic organisms forming plankton. Sporozoa
l They have diverse modes of nutrition – (Sporozoans)
of Organism
DIRECTION OF EVOLUTION
T

photosynthetic, saprobic, parasitic, ingestive or holozoic,

etc. Genetic material is organised in the form of nucleus.
EE

DNA is associated with histone. The aerobic forms possess

mitochondria and other membrane bound organelles.
Flagella, if present are 11-stranded with 9 + 2 organisation
of microtubules.
N

l These organisms with flexible lifestyles justifies the Ciliophora

erection of the intermediate eukaryotic Kingdom (Ciliates)
Chrysophyta
Complexity (Diatoms and related algae) Protista. It is a connecting link between
prokaryotic Monera and the other Zoomastigina
of Cell Pyrrophyta
eukaryotic kingdoms. (Animal flagellates)
(Dinoflagellates)
Eukaryotes Primitive eukaryotic
flagellate

Prokaryotes
Cyanobacteria
(Blue green algae)

Eubacteria
(True bacteria) Archaebacteria
Viruses (Ancient bacteria)
Ÿ Viruses are intermediate between living and non-
living entities. These act as obligate parasites, i.e., KINGDOM MONERA
inert outside the host cell. l It includes basically unicelluar, microscopic
Ÿ They do not grow, divide or reproduce like typical living prokaryotes and the most primitive of living forms
organisms, rather reproduce using host machinery. with different modes of nutrition i.e., – saprobic, parasitic,
Ÿ Viruses are thus described as a nucleoprotein entity chemoautotrophic, photoautotrophic and symbiotic.
which is able to utilise the synthetic machinery of a l Cell wall comprises of peptidoglycan and polysaccharides other
living cell of another organism for its multiplication than cellulose. Cells have one envelope type of organisation but
and division. internal compartmentalisation is absent.
Ÿ They resemble living organisms in possessing genetic l If present, flagella are single stranded, genetic material
material and organic macromolecules and showing is not organised into a nucleus, DNA is naked i.e.,
mutations. without histone, all membrane bound cell
Ÿ They are responsible for a number of infectious organelles are absent. Sexual
diseases in plants, animals and humans. reproduction is absent as meiosis
does not occur.
CONCEPT KINGDOM FUNGI CLASSIFICATION
MAP
Fungi is a large kingdom comprising of about 5100 genera and more than 50,000 species. l Many botanists have classified fungi in different ways.
They are achlorophyllous, heterotrophic, spore forming, eukaryotic organisms with thalloid l Martin’s (1961) classification of fungi is most prevalent. He classified fungi into Myxomycotina
body made up of hyphae (together constituting mycelium). They are cosmopolitan in (Slime molds) and Eumycotina (True fungi).
Martin further divided Eumycotina into the following classes:
distribution. Some fungi occur in fresh or marine water, others are terrestrial and still others
are air borne. The study of fungi is known as mycology.
Phycomycetes
The mycelium is aseptate and coenocytic.
STRUCTURE
l
l The sporangia has innumerable sporangiospores (zoospores or
aplanospores) formed endogenously.
l Fungi range from unicellular, uninucleate forms like yeast l Sexual reproduction is oogamous in Oomycetes, and isogamous in
and Synchytrium to thread-like structure called mycelium Zygomycetes.
NUTRITION REPRODUCTION which is made up of a net like mass of tubular filaments l Biflagellate motile cells (zoospores) are produced by many species.
Fungi may reproduce by vegetative, asexual and sexual means. called hyphae. The hypha is usually branched, tube like l The zygote is unicellular and simple.
l They may be obligate parasites (obtain food from host plants l
structure, having protoplasm with reserve food and l E.g., Albugo, Phytophthora (Oomycetes), Rhizopus, Mucor (Zygomycetes).
and die with the death of host) or facultative saprophytes
(usually parasitic but able to absorb food from decaying host
m
Vegetative
a bounded by a wall of chitin, a nitrogen containing
polysaccharide (C22H54N4O21)n. Ascomycetes
plant as well), obligate saprophytes (obtain food from
decaying organic matter) or facultative parasites (usually
saprophytes but can live parasitically under some conditions).
Budding
gr
Small outgrowths from
vegetative body, cut off

Fission
Splitting of
vegetative

Fragmentation
Fragments of
vegetative hyphae

l The protoplasm of the hypha may be continuous without

cross walls, called aseptate hypha or may have
transverse partitions or septa, known as septate hypha.
l The mycelium consists of septate hyphae, possessing central or septal
pores. Motile structures do not occur in the life cycle.
In majority of Ascomycetes, the common mode of asexual reproduction is
Asexual and mature to form new
individuals, e.g., yeast
le cells into two
daughter cells.
develop into new
individual.
Septa are seldom complete as they are perforated and
may contain plasmodesmata or central pores. When
l
through the formation of conidia.
Sexual reproduction takes place through fusion of sex cells, somatic cells,
Zoospores
Uniflagellate or biflagellate, thin walled, uninu-
cleate structures formed in zoosporangia, e.g.,
Phytophthora, Albugo.
Sexual Te
Sexual reproduction takes place by following processes:
l

central septal pore possesses a barrel-shaped inflation, as

in many basidiomycetes, it is known as dolipore septum.
A membranous vesicle called lomasome is found
attached to plasma membrane.

l
l

gametangial contact between an antheridium and ascogonium and

autogamy.
Karyogamy is delayed after plasmogamy. Hence, a new transitional phase
Sporangiospores
Nonflagellate spores that develop inside

Sporangium Spores
Oogonium
(Female
Fertilisation
tube
Empty
antheridium
on
Gametangial contact
Here gametes are never released
Lipid globule
Vacuole l

called dikaryophase appears in the life cycle. The cells of dikaryophase are
called dikaryotic cells as each cell possesses two nuclei (n + n).
Some dikaryotic cells function as ascus mother cells. Ascus is a sporangial
gameta- (Male from gametangia, instead the male
e Dictyosome (Unicisternal) sac peculiar to Ascomycetes. 4-8 haploid meiospores named ascospores are
sporangia, e.g., Mucor, Rhizopus. ngium) gameta- and female gametangia come in Glycogen particle or oil (Reserve food) produced internally in each ascus.
ngium)
close contact with the help of a
s Nucleus
Endoplasmic reticulum
l The asci may occur freely or get aggregated with dikaryotic mycelium to
Chlamydospores
Thick-walled perennating spores which develop at
places along the hyphae by accumulation of
Ooplasm
Periplasm
do
fertilisation tube, through which one
or more male nuclei migrate to the
female gametangium. E.g., Pythium

Ribosome
Mitochondrion
Cytoplasmic matrix
l
form fructifications called ascocarps.
E.g., Yeast, Aspergillus, Penicillium, Claviceps, morels and truffles.
protoplasm, rounding off and secretion of thick wall. Plasma membrane Basidiomycetes
Planogametic copulation
Anisogametes
Antherozoid
ly
Oidia
Usually formed under conditions of excess

Oidia
(multiply
by

This involves fusion of two

naked motile gametes
(planogametes). Based
upon the nature and

Isogametes Ovum
ai Hyphal wall
(Usually contains chitin)
Fig.: Ultrastructure of part of fungal hypha

l
l

Basidiomycetes are the most advanced fungi and considered among the
best decomposers of wood.
Motile structures or cells are absent. Mycelia are of two types, primary and
secondary.
water, sugar and certain salts, e.g., Rhizopus. budding)
structure of gametes, it is
of three types: isogamy, Flagella
Empty l

D
In some fungi, hyphae may structurally modify in response l Karyogamy is delayed after plasmogamy. A new transitional phase called
antheridium dikaryophase appears in the life cycle. It produces dikaryotic secondary
Conidia
Conidiophore

Conidia
Nonmotile, thin-walled, exogenous spores,
produced in chains upon the tip of hypha called
conidiophore, e.g., Aspergillus, Penicillium.

anisogamy and oogamy.

Isogametangia

Isogamy Anisogamy
Gametangial copulation

Oogamy
This process involves fusion of the
Ka
to functional needs as:
(a) Prosenchyma : It is formed when the component
hyphae lie more or less parallel to one another and
unite to form a rather loosely interwoven structure l

mycelium. Secondary mycelium is long lived, profusely branched septate

hyphae possessing dolipores.
Hook-shaped outgrowths called clamp connections are found on the
T
where their individuality is not lost. sides of septa which are meant for proper distribution of dikaryons at the
entire contents of two compatible
Ascopores (b) Pseudo-parenchyma : It is formed when the hyphae time of cell division.
gametangia, resulting in karyo-
Karyogamy and meiosis occur in club-shaped structures known as basidia.
Ascospores
Nonmotile meiospores which are produced
inside special sacs called asci and are
characteristic of Class Ascomycetes.
Ascus

Suspensor
Somatogamy
gamy. E.g., Mucor.
Here sex organs are not at all formed, but two vegetative hyphae
lose their individuality.
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become closely interwined, forming a tissue which
consists of hollow tubes spread in all directions. These
(c) Rhizomorph : It is a thick strand or root-like

l
l

A basidium commonly produces four meiospores or basidiospores

exogenously at the tip of fine outgrowths called sterigmata.
The fungi may or may not produce fructifications called basidiocarps
Basidiospores

or cells take over the sexual function and fuse together. E.g.,
Morchella, Peziza.
N
aggregation of somatic hyphae which lose their
individuality. The entire mass behaves as an organised
l
that vary in size from microscopic to macroscopic forms.
E.g., Puccinia, Ustilago, Agaricus, bracket fungi, etc.
Sterigma
Nonmotile meiospores formed exogenously Spermatisation unit and have higher infection capacity.
Basidium
on short outgrowths of club-shaped structure In some advanced genera, the sexual process is accomplished by (d) Sclerotium : It is a compact globose structure, formed Deuteromycetes
called basidium and are characteristic of Class minute spore-like spermatia (male gametes) and specialised by the aggregation and adhesion of hyphae. l Deuteromycetes is an artificial class of fungi which has been created to
Basidiomycetes. receptive hyphae (female gametes). The spermatia are carried by (e) Appressorium : It is a terminal, simple or lobed,
include all those fungi in which sexual stage is either absent or not known.
air, water or insects to the receptive hyphae. The contents of the swollen structure of germ tubes or infecting hyphae, l Some of the deuteromycetes are unicellular like yeast.
Binucleate spores spermatium enter the receptive hyphae through a pore. found in many parasitic fungi. l The mycelium is usually septate. Coenocytic forms are not known.
Dikaryotic spores meant for multiplying Receptive hyphae (f ) Haustorium : These are intracellular, absorbing l Asexual reproduction often occurs by conidia along with some other
the dikaryotic mycelium, e.g., aecidio- (Oogonium) structures of obligate parasites meant for absorbing types of spores.
spores, uredospores in Puccinia. Another Trichogyne food material from the host. They may be variously l It is believed that most members of deuteromycetes are actually ascomycetes
type of dikaryotic spore is teleutospore
Uredo- Teleut- shaped and secrete specific hydrolysing enzymes. in which sexual reproduction is either absent or yet to be discovered.
or teliospore . Aecidio- spore ospore Spermatium l E.g., Colletotrichum, Helminthosporium, Trichoderma.
spore
 Reproduction
CONCEPT LICHENS Lichens reproduce both by asexual and sexual means.
MAP
Asexual reproduction Sexual reproduction
Lichens are composite or dual organisms representing an intimate symbiotic relationship
between algae and fungi (De Bary, 1879). The algal component of lichen is known as Asexual reproduction occurs by following structures: In lichens, the process of sexual reproduction is performed only by the fungal
phycobiont whereas the fungal component is known as mycobiont. The fungal component (i) Cephalodium : These appear as small, hard, dark- component. The female sex organs are known as carpogonia. The male sex organs are
predominates algal component, such an association is known as helotism (Crombic, 1885). coloured, gall-like swellings on the free surface of some known as spermogonia. A carpogonium is differentiated into a basal coiled
There are about 400 genera and 1600 species of lichens. They usually grow on bark of trees, lichen thalli. They contain the same fungal hyphae as in ascogonium and an elongated multicellular trichogyne. Each spermogonium is a
the thallus but the algal component is always different. flask- shaped receptacle immersed in a small elevation on the upper surface of thallus.
dry logs (corticolous), bare rocks (saxicolous) or soil (terricolous), etc. The spermogonium usually develops close to carpogonium.
(ii) Soredium : Small bud-like outgrowths over the upper
surface of thalli, containing one or few algal cells Ostiole (small pore)
Upper cortex Trichogyne
closely enveloped by a weft of fungal hyphae. Both
(straight upper portion
fungus and alga are same as in parent thallus. projecting above the
m (iii) Isidium : These are small outgrowths on the upper surface of thallus)
Classification Internal Structure surface of the lichen thallus each consisting of an outer
a cortical layer made up of fungal cells followed by an Algal cells
On the basis of
fungal component gr algal layer of the same kind as in the thallus.
Cephalodium
Parent lichen

Algal cells
Spermatia
(non-motile
Ascolichens Upper cortex
Composed of compactly interwoven fungal
le thallus male cells)
Stroma
Helical
ascogonium
(coiled portion
The fungal component of these
lichens is a member of Class
Ascomycetes. They are called
gymnocarpeae if the fruiting

hyphae arranged at right angles to the surface

of thallus, usually lacking intercellular spaces (if
present, then filled with gelatinous substance).
Te Algal cell
Medulla
Fertile hypha
Spermogonium
Medulla
sunken in medulla)
Carpogonium
Spermatia adhere to the projected part of sticky trichogyne. On dissolution of the walls
Fungal hyphae
body is a disc like apothecium
(also known as discolichens, e.g.,
Parmelia). They are called pyreno-
carpeae if the fruiting body is a

Algal zone
This layer is composed of green or blue green
algae. The algal cells remain embedded in the
on Fungal
hyphae

Cephalodium between them the nucleus of spermatium migrates into the carpogonium through
trichogyne. The male nucleus fuses with the female nucleus. Several branched
ascogenous hyphae develop from the base of the fertilised ascogonium. The terminal
binucleate cell of ascogenous hypha develops into an ascus. The two nuclei within the
tangled network of fungal hyphae. Sometimes e
flask shaped perithecium (also algal cells and fungal hyphae are uniformly ascus fuse to form a diploid nucleus which forms eight haploid daughter nuclei
s Algal cell
known as pyrenolichens, e.g., meiotically, each metamorphosing into an ascospore. The ascospores are hyaline and
distributed throughout the thallus (homo-
Dermatocarpon). green or brown in colour. They are released gradually from the ascus, and on coming in
isomerous) whereas sometimes algal cells form
Basidiolichens
The fungal component of these

a distinct layer within thallus (heteromerous).

Medulla
do Soredium Algal cells
Isidia contact with a suitable alga, form a new lichen thallus.
Ascospores (haploid spores which
come in contact with alga to form new lichen)
Ascus (sac like
lichens is a member of Class Central part of thallus, comprised of loosely
interwoven fungal hyphae with large spaces ly Upper cortex Paraphysis
(Sterile hair
structure
Basidiomycetes. Genera like
Corella and Dictyonema belong to
this group.
between them.
Lower cortex
ai Algal cells

like fungal
hyphae)

containing
ascospores)
Upper cortex
Deuterolichens
Composed of compactly arranged fungal
hyphae running parallel or perpendicular to
D Medulla
Isidium

Ascocarp
Algal cells
The fungal component of these surface of thallus.
lichens belongs to Class Deutero-
mycetes. Rhizines
Some hyphae of lower cortex descend down
A part of vertical
Economic Importance Ka Lower cortex
Fruiting body of lichen

Fungal cell
and help in attachment of thallus to substratum. (i) As food : Species of Lecanora, Parmelia, Umbilicaria and Cetraria islandica are used as food in many parts of the world. Umbilicaria esculenta is a
On the basis of
external morphology
These are known as rhizines.
section of lichen T
delicacy in Japan, while the species of Parmelia are used as curry powder in India.
(ii) As medicine : Parmelia perlata is specially useful in dyspepsia and in the treatment of snake and scorpion bites. Cladonia, Cetraria and Pertusaria
Crustose lichen Foliose lichen Fruticose lichen

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are used in intermittent fever. Cladonia pyxidata is useful in whooping cough. Usnea sp. are used to stop bleeding. Erythrin, obtained from
Roccella montagnei, is used in angina. Lobaria pulmonaria and Cetraria islandica are used in tuberculosis and other lung diseases.
(iii) As dyes : Red and purple dyes are obtained from Ochrolechia androgyna and O. tartarea. Orchil, a blue dye is obtained from some lichens (e.g.,
These are encrusting lichens with an inconspicuous,
thin and flat thallus, firm in texture. The thallus is very
These lichens are flat with leaf-like and
lobed thallus attached to the substratum
Shrub-like, cylindrical and branched thallus
that grow erect or hang from the substratum

N
Cetraria islandica). Parmelia omphalodes is the source of a brown dye. Litmus, an important acid-base indicator dye in chemical laboratories, is
obtained from Roccella montagnei and Lasallia pustulata.
(iv) In tanning industry : Cetraria islandica and Lobaria pulmonaria are used as tanning agents in leather industries.
closely adhered to the substratum and provides a with the help of rhizoid - like rhizines. with the help of a basal mucilagenous disc. (v) In cosmetics : Evernia and Ramalina are the source of essential oils, used in the manufacture of cosmetic soaps. Ramalina calicaris is used for
crust-like appearance. Examples: Parmelia, Physcia. Examples: Alectonia, Cladonia. whitening hair in wigs. Pseudevernia furfuracea and Evernia prunastri are widely used in the manufacture of perfumes.
Examples: Graphis, Haematomma, Lecanora.
Ecological Significance
Lichens are pioneer plants in ecological succession, which help in colonisation of bare rocky habitats. They secrete some organic acids which
disintegrate rocks and form soil and substratum for subsequent establishment of other vegetation types. Lichens can be used as air pollution
indicators especially of the concentration of sulphur dioxide in atmosphere. Several lichens are also harmful to us. They cause a considerable loss
Crustose lichen Foliose lichen Fruticose lichen due to etching of glass surfaces and marble stones. Some lichens, such as Letharia vulpina (wolf moss) are poisonous.
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 Leaf is an important vegetative organ of plant as it is specialised to

CONCEPT MORPHOLOGY
perform photosynthesis. It is a green lateral flattened outgrowth borne
on the node of a stem or stem branch and bears a bud in its axil.

MAP OF LEAF
Parts of
a leaf
A typical leaf consists of three parts - leaf base,
petiole and lamina. Leaf base is the basal part of the
leaf by which it is attached to the node of the stem.
Different plants have different types of leaf bases viz.
pulvinus, e.g., pea; sheathing, e.g., Zea mays; decurrent, e.g.,
Crotolaria and amplexicaul, e.g., Polygonum. Leaves of some
plants have lateral appendages on each side of leaf base, known
as stipules which may be caducous, deciduous or persistent.
Petiole is the leaf stalk that joins the lamina to the stem or its
Opposite
superposed branch. Sometimes the petiole is absent and then the leaf is
Whorled Phyllotaxy said to be sessile.
Phyllotaxy is the arrangement of Lamina is the expanded, green and conspicuous part of
leaves on the stem or its branches in such leaf which is specialised to perform photosynthesis.
a way that all the leaves get proper exposure It is supported by veins and veinlets which
to sunlight. Phyllotaxy is of three main types – contain vascular tissues for conduction
Alternate
(I) Spiral or alternate : A single leaf is borne at of water, mineral salts and Leaf apex
each node, e.g., Hibiscus, mango. prepared food.
(ii) Opposite : A pair of leaves are borne at each
Leaf margin
node on opposite sides, e.g., Quisqualis (opposite

m
Axillary bud
Opposite decussate superposed) and Calotropis (opposite Lateral vein
Mid vein
decussate).

a
Lamina
(iii) Whorled or verticillate : More than

gr
two leaves arise at each node, e.g.,
Alstonia. Petiole
Stipule

le
Stem branch
Leaf

Te
tendril Fig.: A typical
on dicotyledonous leaf

s
ave
Sim
ple
le Leaf modifications
e

Fig.: (i) Leaf tendrils : Leaves are modified into

Simple and slender, wiry often closely, coiled structures, known as
s

tendrils, which help in climbing. These may be whole leaf

Compound leaves
do

tendrils (e.g., Lathyrus aphaca), leaflet tendrils (e.g., Pisum

A simple leaf is the one in which lamina is undivided or sativum), petiolar tendrils (e.g., Nepenthes), leaf tip tendrils (e.g.,
incised to any depth but not upto the midrib. In a compound leaf, Gloriosa), Stipular tendrils (e.g., Smilax), etc.
lamina is completely broken up into distinct segments called leaflets (ii) Leaf spines : These protect the plants from grazing animals and
excessive transpiration e.g., Solanum surattense.
ly

which are separately articulated at the base. Compound leaves are of 2

types - (iii) Leaflet hooks : The terminal leaflets of compound leaves become
transformed into stiff claw-like and curved hooks. These help the plant in
ai

(a) Pinnate compound leaves : In these type of leaves, incision of lamina is

directed towards the midrib which is known as rachis. Leaflets are arranged on climbing, e.g., Doxantha unguis-cati.
both sides on the rachis or on its branches. These are of following types: (iv) Phyllodes : These are the flattened petioles or parts of the rachis which
D

(i) Unipinnate : Leaflets are directly attached on the rachis, e.g., Cassia fistula perform the function of photosynthesis, e.g., Acacia species. These help to
(paripinnate), rose (imparipinnate). reduce transpiration in xerophytic plants.
(ii) Bipinnate : Rachis divides and gives rise to secondary axis on both sides on which (v) Insect catching leaves : Leaves are modified to form pitchers (e.g.,
Ka

Nepenthes), bladders (e.g., Utricularia) etc. to trap and digest insects.

leaflets are arranged, e.g., Acacia.
(vi) Succulent leaves : These are fleshy leaves that store food material,
(iii) Tripinnate : Secondary axis too, divides and gives rise to tertiary axis on which
e.g., Aloe, Agave etc.
leaflets are attached, e.g., Moringa.
(vii) Scale leaves (or cataphylls) : These are dry, membranous
(iv) Decompound : Rachis divides more than three times and gives rise to small
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leaves which do not take part in photosynthesis, e.g.,

axis on which leaflets are arranged, e.g., carrot. Casuarina.
(b) Palmate compound leaves : In these type of leaves, incision of leaf is
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(viii) Floral leaves : These are specialised

directed towards the petiole due to which all leaflets seem to be leaves i.e., sepals, petals, stamens and
articulated on the upper end of petiole. It does not have any rachis. carpels.
Depending on the number of leaflets present, a palmate
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compound leaf is called unifoliate (e.g., Citrus), bifoliate

( e.g., Balanites ), trifoliate ( e.g., Trifolium ),
quadrifoliate ( e.g., Paris quadrifoliata ), Leaf
multifoliate (e.g., Bombax). spine
Leaf
pitcher

Venation
Venation is the arrangement of veins
and veinlets on the lamina of a leaf.
Venation is of 3 main types - reticulate (veins
form a network), parallel (veins run parallel) and
furcate (veins branch dichotomously, e.g., Circeaster).
Pinnate Palmate
Reticulate venation is found in most dicots. Pinnate
(or unicostate) reticulate venation occurs in Ficus
Fig.: Compound leaves religiosa. Palmate (or multicostate) reticulate venation
occurs in Zizyphus (convergent), and Luffa (divergent). Parallel
Parallel venation occurs in most monocots. Pinnate
Functions of (or unicostate) parallel venation occurs in banana.
the leaves Palmate (or multicostate) parallel venation
Primary functions: Photosynthesis, occurs in bamboo (convergent) and
gaseous exchange, transpiration, protection Livistonia (divergent).
of buds and conduction through veins.
Secondary functions : Storage e.g., succulent
leaves of Aloe, Agave etc.; protection e.g., spiny Reticulate
leaves of Barberry, Opuntia etc.; support e.g.,
leaflet hooks in Doxantha; nitrogen nutrition
e.g., leaf pitchers of Nepenthes; reproduction
e.g., leaves of Bryophyllum help in
vegetative propagation; floral
leaves help in sexual Fig.: Types of venation
reproduction.
 Inflorescence is the arrangement and distribution of flowers on the

CONCEPT INFLORESCENCE
shoot system of a plant. The axis of the inflorescence is called
peduncle, whereas the stalk of individual flower is called pedicel. A
flattened peduncle is known as receptacle. Inflorescence is of five

MAP types- solitary, racemose, cymose, mixed and special.

Compound
racemose
Compound racemose inflorescence is an
indefinite or indeterminate inflorescence in
which the peduncle is branched repeatedly once
Solitary or twice in a racemose fashion. It is of following
terminal types–
Single flower occurs on Solitary (a) Compound raceme or panicle, e.g., goldmohur,
the terminal part of a Flowers occur singly or are Cassia fistula, Yucca.
branch, e.g., poppy. separated from other flowers (b) Compound spike or spike of spikelets, e.g., wheat.
of the same plant by (c) Compound spadix, e.g., coconut, date, banana.
vegetative regions. (d) Compound corymb, e.g., Pyrus, cauliflower.
(e) Compound umbel, e.g., Daucus carota,
fennel, Coriandrum sativum.
Solitary (f ) Compound capitulum, e.g.,
axillary Echinops.
Single flower occurs in
the axil of a leaf, e.g.,
Petunia, China rose.
Solitary
axillary

a m
Racemose

gr
It is an indeterminate inflorescence
which shows indefinite growth. The Catkin

le
arrangement of flowers is either
Dichasial
acropetal (vertical orientation of
cyme Polychasial cyme

Te
axis) or centripetal
(horizontal orientation
Cymose of axis).
A determinate inflore - Spike
scence in which the tip of main Raceme
on
axis terminates in a flower and further Umbel
Helicoid growth continues by one or more lateral
cyme Cymose branches. The arrange-ment of flowers is
head
either basipetal (vertical orientation Simple
e

of axis) or centrifugal Raceme

racemose
s

(horizontal orientation of Peduncle is elongated having

Simple racemose inflore- pedicellate flowers in an acropetal
axis).
do

Cymose scence is an indefinite fashion, e.g., Lupinus, Raphanus,

inflorescence in which Linaria.
head the peduncle is
Sessile or subsessile flowers unbranched.
ly

are borne centrifugally Spike

around a receptacle, e.g., An elongated peduncle bears sessile
Scapigerous
ai

Albizzia, Anthocephalus Umbel flowers in an acropetal fashion, e.g.,

cadamba, Acacia. Head All the pedicellate flowers arise from a single Achyranthes, Callistemon, Adhatoda
D

The leafless flowering axis point in a centripetal fashion. The peduncle is vasica.
known as scape bears clusters very much reduced, e.g., Hydrocotyle, Prunus.
of flowers that form a head
Ka

which is covered by spaths, Spikelet

With long peduncle

With short peduncle

Biparous or e.g., Allium cepa. Corymb Spikelets are small and few flowered
Dichasial cyme The main axis is comparatively short, and the spikes which are surrounded at the
A terminal flower is subtended lower flowers have much longer pedicels than base by two scales or glumes, e.g.,
rice, bamboo, oat, etc.
T

by two lateral branches which the upper ones so that all the flowers are brought
also end in flowers. The process is more or less to the same level, e.g., Iberis amara .
EE

repeated. Inflorescence axis is Catkin

multipodial, e.g., Spergula, Multiparous Corymbose raceme Pendulous spike which bears naked
Stellaria media, The young flowers appear to be arranged like a
Clerodendrum.
or Polychasial cyme pistillate or staminate flowers, (but
corymb but in mature state the longer pedicels
N

More than two lateral branches not both) e.g., mulberry, poplar, Salix,
continue the growth of of the lower flowers do not bring them to the Quercus.
inflorescence when the parent level of upper ones, e.g., mustard.
axis ends in a flower, e.g.,
Spadix
With flattened

Uniparous or Hamelia, Calotropis, Capitulum

peduncle

Asclepias. The flattened receptacle bears numerous sessile Spike with fleshy peduncle and
Monochasial cyme and small florets (ray florets and disc florets) in a having both male and female flowers.
A single lateral branch arises from the centripetal manner, e.g., Zinnia, Sunflower, Cosmos. It is surrounded by a large green or
peduncle of old flower which terminates coloured bract called spathe, e.g.,
in a flower. The lateral branch also palm, Colocasia, Musa.
terminates in a flower. It is of two types:
(a) Helicoid cyme – All the flowers are borne Cyathium
on the same side forming a sort of helix, e.g., The inflorescence looks like a
Drosera, Begonia, Myosotis. flower. The bracts or the involucre
(b) Scorpioid cyme - Flowers are become fused to form a cup shaped
Hypanthodium
alternately borne on both the sides, structure. The inflorescence contains It has a flask-shaped fleshy
e.g., Tecoma, Ranunculus, pedicellate, achlamydeous, unisexual receptacle which possesses a
Heliotropium. flowers of both the types, male and narrow apical opening guarded by
female. The cup encloses a single hairy structure. The receptacle bears
female flower surrounded by a male flowers towards the pore and
large number of male flowers. female flowers towards the
E.g., Euphorbia Hypanthodium base. E.g., Ficus religiosa,
Mixed pulcherrima. Ficus carica.
Two or more t ypes of
inflorescences get mixed up to
form a mixed inflorescences. It is of
following types:
(a) Panicle of spikelets, e.g., oat, rice. Cyathium Verticillaster
(b) Corymb of capitula, e.g., Ageratum Verticillaster
conyzoides. Two dichasial cyme inflore-
(c) U m b e l o f c a p i t u l a , scences develop from axil of
raceme of capitula. opposite leaves. They together
(d) Thyrsus, e.g., Special form a false whorl around the
grapevine. node, e.g., Ocimum, Leucus.
 MORPHOLOGY
A true fruit (or eucarp) is a ripened ovary. It consists of a thin or thick pericarp
formed from the wall of ovary and seeds formed from the ovules. A fruit in which
other floral parts (e.g., thalamus, base of sepals, petals, etc.), participate in its

CONCEPT OF FRUITS
formation is called false fruit (or pseudocarp) e.g., apple and pear. The seeds

MAP
within the fruits have reserve food for nourishing the young seedlings till they
become nutritionally independent.
· Some fruits are formed without fertilisation i.e., seedless fruits. They are called as

AND SEEDS parthenocarps (e.g., banana). Fruits are classified into three main categories –
simple fruits, aggregate fruits and composite fruits.

Composite fruits Aggregate fruits

A composite or multiple fruit develops from the whole Aggregate fruits are the groups of fruitlets which
inflorescence. It is of two main types: sorosis and syconus. develop from the multicarpellary, apocarpous
Simple
Sorosis : These fruits develop from spike, spadix or catkin ovaries. The individual carpel or pistil develops
fruits inflorescence. Sorosis of pineapple develops from an into a fruitlet and these fruitlets occur as a
Simple fruits develop from intercalary spike of sterile flowers with persistent bracts. clustered unit on a single receptacle, which is
monocarpellary ovary or Sorosis of mulberry develops from a female catkin. referred to as an aggregate fruit or etaerio, e.g.,
multicarpellary syncarpous ovary. etaerio of achenes (Ranunculus, lotus), etaerio of
Syconus : It develops from hypanthodium inflorescence.
Simple fruits may be dry (pericarp is Receptacle becomes fleshy and edible, many achenes follicles (Calotropis), etaerio of berries (Custard
undifferentiated) or succulent develop from pistillate flowers, e.g., Ficus carica. apple), etaerio of drupes (e.g., Rubus idaeus), etc.
(pericarp is differentiated into
epicarp, mesocarp and
endocarp).
Dry fruits
Dry fruits are of
three types – Achenial
(single seeded, indehiscent),

m
capsular (many seeded, dehiscent) Etaerio Etaerio of berries
and schizocarpic (many seeded, Sorosis of Syconus of of achenes in Custard

a
after ripening divide into Morus Fig in Lotus Apple
Seed
single seeded

gr
Seed is a
segments). ripened ovule
which contains an

le
embryo, adequate reserve food
and a covering for protection against

Te
mechanical injury. A seed may have 1 or 2
coverings called seed coats. Outer is
Succulent fruits testa and inner is called tegmen.
Succulent fruits can be divided into three main types: berry, drupe and pome. Seeds can be endospermic
on
(i) Berry : In superior or true berry (derived from superior ovary) usually all the three and non-
layers of fleshy pericarp are edible, e.g., grape, tomato. In inferior or false berry endospermic.
(derived from inferior ovary) epicarp is fused with thalamus to form exocarp, e.g.,
e

banana (parthenocarpic), guava. There are some special berries also such as
balausta (e.g., pomegranate), pepo (e.g., cucumber), and hesperidium (e.g.,
s

orange). (i) Endospermic or albuminous (ii) Non-endospermic or exalbuminous

do

(ii) Drupe (or stone fruit) : In this fruit, epicarp forms the rind, mesocarp is fleshy seeds: Endosperm is present and seeds : The endosperm is consumed during
and endocarp is hard and stony, e.g., almond, mango, Zizyphus, etc. food reserve remains in endosperm, seed development and the food is stored in
(iii) Pome : It is a false fruit that develops from the fleshy thalamus of multicarpellary, e.g., most monocots and some dicots cotyledons, e.g., majority of dicot seeds (Cicer
syncarpous, inferior ovary, e.g., apple, pear, etc. (Ricinus communis). arietinum) and in some monocot seeds.
ly

Testa Tegmen
Perisperm Cotyledon
ai

Endosperm
D

Testa
Caruncle
Ka

Inferior Berry Embryo

Pome of Apple Berry of Tomato Drupe of Mango Radicle Cotyledon Axis
of Banana
Castor seed (L.S.) Gram seed (split open)
T
EE

Achenial fruits (Indehiscent fruit) Capsular fruits (Dehiscent fruit) Schizocarpic fruits (Splitting fruits)
N

Achenial fruits are of five types : Capsular fruits are of five types: Schizocarpic fruits are of five types :
(i) Achene : It develops from monocarpellary, superior, (i) Legume (or pod) : The fruit develops from superior, (i) Cremocarp : It develops from a bicarpellary,
unilocular and uniovuled ovary, pericarp is free from seed monocarpellary, unilocular ovary with marginal placentation. It syncarpous, bilocular, inferior ovary. On maturity, the
except at one point, e.g., Mirabilis jalapa. (ii) Caryopsis (or dehisces by both dorsal and ventral sutures, e.g., members of family fruit splits into two mericarps, each with one seed,
Grain) : It develops from monocarpellary, superior, unilocular Leguminosae. (ii) Follicle : The fruit dehisces by only one suture, e.g., members of family Apiaceae. (ii) Lomentum : The
ovary. Pericarp is completely fused with the testa, e.g., members e.g., Delphinium. (iii) Siliqua : It develops from a bicarpellary, fruit is a modification of legume, which is constricted
of family Poaceae. (iii) Cypsela : It develops from bicarpellary, superior ovary with parietal placentation and a false septum called in between the seeds, e.g., Mimosa, Acacia, etc.
syncarpous, inferior and unilocular ovary. Pappus may be replum. It dehisces by two valves, e.g., members of family (iii) Carcerulus : At maturity, the fruit breaks up into
present for dispersal, e.g., Taraxacum. (iv) Nut: Pericarp becomes Brassicaceae. (iv) Silicula : It is a shortened and flattened siliqua, single seeded indehiscent mericarps, e.g., Althaea.
h a r d , w o o d y o r l e a t h e r y. Fr u i t m a y d e v e l o p f r o m e.g., Capsella bursa-pastoris. (v) Capsule: According to the mode of (iv) Compound samara : At maturity, the fruit splits
monocarpellary, superior ovary (e.g., cashew nut); tricarpellary, dehiscence, capsule may be porocidal capsule (e.g., Papaver), up into single seeded winged mericarps, e.g., Acer.
syncarpous, trilocular ovary (e.g., litchi), etc. (v) Samara : denticidal capsule (e.g., Pink), pyxidium (e.g., Portulaca), (v) Regma : It develops from multicarpellary pistil and
Pericarp becomes flat like wings and thus help in wind dispersal loculicidal capsule (e.g., Gossypium), septicidal capsule on maturity, splits into as many cocci as the number of
e.g., Holoptelea. (e.g., Viola), septifragal capsule (e.g., Datura), etc. carpels, e.g., Geranium.

Cremocarp of Coriandrum

Samara of Cypsela of Taraxacum Legume of pea

Holoptelea

Follicle of
Capsule of Delphinium Carcerulus of Lomentaceous pod Regma of
Datura Althaea of Touch-me-not Castor

Caryopsis of
Maize
Nut of Litchi
Siliqua of Silicula of
Achene of Mirabilis Mustard Capsella Double samara of Acer
jalapa
 A flower is a highly condensed and modified shoot. It contains reproductive organs of the flowering plants, which develop fruits and seeds. There are four types
of floral organs viz. sepals, petals, stamens and carpel or pistil. A flower having all the four types of floral organs is known as complete flower e.g., cotton. If
CONCEPT
FLORAL
one or more of the floral organs are absent it is called incomplete flower e.g., cucurbits. A flower having both the essential organs i.e., stamens and carpels is
called hermaphrodite or bisexual flower, e.g., China rose, whereas a flower having only one of the two essential organs is known as unisexual flower e.g., mulberry.
MAP
Flowers having only stamens are called staminate flowers and those having only carpels are called pistillate flowers. On the basis of symmetry flower can be
actinomorphic (two equal halves in any plane), zygomorphic (two equal halves in one plane), or asymmetrical.
MORPHOLOGY ANDROECIUM
l Third and male whorl of the flower made up of
stamens (microsporophylls) which consist of

COROLLA
l Second whorl inner to calyx made up of petals
which protects the inner whorls and attracts insects
for pollination. Corolla may be polypetalous (petals free)
filament (lower stalk-like part which may be absent in or gamopetalous (petals fused).
some), anther (upper swollen part usually having two lobes or l Polypetalous corolla may be cruciform (four clawed or
GYNOECIUM theca i.e., bithecous or in some monothecous, e.g., Althaea) and
connective (sterile band which connects two anther lobes). In Salvia,
unguiculate petals arranged cross wise e.g., mustard), caryophy-
l Central, female reproductive part l The stamens may be equal llaceous (five unguiculate or clawed petals with limbs placed at right
or unequal in length. When there is connective forms a long curved structure, its one end has a fertile anther angles, e.g., Dianthus), rosaceous (five or more sessile or shortly clawed
which develops from thalamus and lobe and other has a sterile anther lobe. Stamens may be shorter than other
consists of carpels (megasporophylls). m
two long and two short stamens, the petals with limbs spread regularly outwards, e.g., rose), campanulate or bell-
condition is called didynamous, e.g., whorls (inserted) or may protrude out of the flower (exserted). shaped (e.g., Physalis), papilionaceous (five unequal or irregular petals viz.
l Each carpel consist of– stigma (the tip which
receives pollen), style (elongated structure
a
Ocimum. When out of six stamens, four are longer l On the basis of attachment to the filament, anthers can be adnate (filament runs 1 standard or vexillum – posterior largest–, 2 wings or alae –lateral, smaller– and
connecting stigma and ovary), ovary (lower swollen
part containing ovules).
l On the basis of number of carpels present, it can be
gr
in inner whorls and two in outer whorl are shorter,
the condition is called tetradynamous, e.g., mustard.
l Dehiscence of anthers to expose the pollen grains
can be longitudinal (long slits appear lengthwise e.g.,

along the back of the anther or becomes continuous with the connective, e.g.,
Ranunculus), basifixed (filament fixed at anther its base, e.g., Datura), dorsifixed
(filament attached to back and anther immobile, e.g., Passiflora), versatile (filament
attached to back and the anther can swing freely, e.g., grasses).

2 anterior petals fused together to form keel or carina).

l Gamopetalous corolla may be campanulate (bell-shaped or inverted cup
shaped e.g., Campanula), urceolate (urn-shaped e.g., Bryophyllum), tubular
(tube-like or cyclindrical e.g., disc floret of sunflower), infundibuliform (funnel
moncarpellary (one carpel only) or multicarpellary
(many carpels) which can be apocarpous (carpels free e.g.,
Ranunculus) or syncarpous (carpels fused e.g., Petunia).
le
mustard), transverse (breadthwise slits, e.g., Malva),
porous (pores appear at the tip e.g., Solanum or base
l The cohesion between the stamens may be monadelphous (all the filaments
united into a single bundle, anthers free, e.g., China rose), diadelphous (filaments
united in two bundles, anthers free, e.g., pea), polyadelphous (filaments united

shaped e.g., Petunia), rotate (corolla with short tube having limbs placed
transversely like a saucer or the spokes of a wheel, e.g., Solanum nigrum),
salver shaped or hypocrateriform (tubular corolla with spreading lobes,
l On the basis of number of locules (chamber) present in
the ovary, it can be unilocular (pea), bilocular
(mustard), trilocular (Asparagus), tetralocular
(Ocimum), pentalocular (China rose) or
l Longitudinal dehiscence may be laterorse (slitsTe
e.g., Cassia), valvular (split at several places by lifting of
surface layers, e.g., Barberry), irregular (e.g., Najas).
on sides), introrse (slits towards the inner side
or centre of the flower), extrorse (slits lie

into more than two bundles, anthers free, e.g., castor), syngenesious (anthers
united into a bundle, filaments free, e.g., sunflower), synandrous (anthers as
well as filaments united throughout the length, e.g., Colocasia). The free
stamens are called polyandrous.

e.g., Clerodendrum), bilabiate (bilipped corolla with gaping, wide open

mouth, e.g., Ocimum), personate (bilipped corolla with closed lips,
e.g., Antirrhinum), ligulate or strap-shaped (short and narrow
tube-like corolla with upper part flattened like a strap, e.g.,
multilocular (Althaea).
towards the outer side of flower).
on l On the basis of adhesion of stamens to flower, it can be
epiphyllous (attached to perianth, e.g., Asphodelus),
epipetalous (attached to petals, e.g., Datura),
gynandrous (attached to gynoecium, e.g.,

ray floret of sunflower), spurred (one or more petals

drawn out like a beak or spur, e.g., Larkspur).
Calotropis).
PLACENTATION e
l Arrangement of placenta (which bear s
ovules) on the ovary wall which can be :
AESTIVATION
(i)Marginal : One or two longitudinal alternate
rows of ovules along the ventral suture in unilocular
ovary, e.g., pea, Cassia etc.
(ii)Parietal : Ovules on walls of bi–multicarpellary but
unilocular ovary e.g., Argemone.

Stigma
Style
do Pollens
l Arrangement of petals (or sepals) in a
flower bud with respect to members of the
same whorls which can be open (margins of
adjacent petals sufficiently apart from each other),
(iii) Axile : In multicarpellary, syncarpous, multilocular Ovary ly Anther
valvate (margins of the adjacent petals lie close,
without overlapping, e.g., mustard), twisted or contorted
gynoecium; margins fuse at the centre of the ovary to form
an axis which bears ovule e.g., Solanum.
(iv)Free central : Unilocular ovary with ovules borne on
central axis e.g., Dianthus.
ai Filament
(one margin of a petal overlaps the margin of an adjacent
petal (external) and the other margin is overlapped (internal)
by the margin of adjacent petal, e.g., China rose), imbricate
(one petal external, one internal; and of the remaining three
(v)Basal : Ovary unilocular with a single ovule at its
base, e.g., sunflower.
(vi)Superficial : Multicarpellary, syncarpous Ovule

D petals one margin is overlapped, other overlapping, e.g.,

Cassia), quincuncial (special type of imbricate aestivation
in which two petals external, two internal and in one
gynoecium bears a large number of
ovules that are borne on the walls of
loculi without specific order,
e.g., Nymphaea.
Ka petal one margin is overlapped, one is overlapping,
e.g., calyx of Cucurbita maxima), vexillary
(posterior petal overlapping the two lateral
petals, the latter overlapping the two
anterior petals, e.g., pea).
THALAMUS
(Torus/Receptacle)
T
l Broadened or swollen part of the flower which
lies at the tip of the pedicel and bears floral organs.
l In most flowers the thalamus is condensed but in some,
one or more internodes elongate viz. anthophore BRACTS
EE CALYX
l Outermost whorl made up of sepals
which are usually green but sometimes
coloured (i.e., petalloid). They protect the inner
(internode between calyx and corolla e.g., Dianthus),
androphore or gonophore (internode between corolla and
androecium, e.g., Passiflora), gynophore (internode between

N
l Specialised leaves from the axil of
which flower arise. They can be foliaceous
(leaf-like e.g., Adhatoda), petaloid (like petals,
whorls and carry out photosynthesis when green.
l The sepals may be free (polysepalous) or
androecium and gynoecium, e.g., Capparis), gynandrophore or fused(gamosepalous). They can be caducous (fall just at
e.g., Bougainvillea), scaly (membranous, small the time of opening of bud, e.g., poppy), deciduous
androgynophore (both androphore and gynophore present, e.g., e.g., sunflower), spathy (large, boat-shaped bract
Gynandropsis pentaphylla), carpophore (the thalamus in (attached till the flower withers, e.g., mustard), persistent
enclosing an inflorescence, e.g., banana, maize), (remain attached to the fruit, e.g., tomato).
between the two carpels elongates and after bifurcation glumes (small, dry, scaly as in spikelet of Poaceae ).
protrudes out of the two carpels, e.g., Coriandrum). PEDICEL OR l There are one or more whorls of bracts found at
l Sepals can be modified to form pappus (hairy structure
which helps in dispersal e.g., sunflower), leafy petalloid
l On the basis of relative position of floral organs on
thalamus flower may be epigynous (ovary inferior,
STALK the base of calyx which form epicalyx in most (large leaf like coloured structure, e.g., Mussaenda),
l Lower internode of flower. members of Malvaceae, e.g., China rose.
p l a ce d b e l ow o t h e r w h o r l s, e. g. , g u ava ) , spinous (persistent and modified into spines, e.g.,
A flower with pedicel is called Sometimes, bracts are in one or more whorls
hypogynous (ovary superior, e.g., China rose), or Trapa), spurred (drawn out into beak or spur, e.g.,
pedicellate and one without around and below the entire inflore-
perigynous (ovary half superior or half Larkspur), hooded (modified into a hood,
it, is sessile. It may bear scence, e.g., coriander and are called
inferior and thalamus may be disc e.g., cover ing the whole flower, e.g.,
bracteoles along with involucre.
pea, cup e.g., Prunus or flask Aconitum) or bilabiate (two-
the bracts. lipped, e.g., Salvia).
e.g., rose shaped).
N
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 Hyoid apparatus Respiratory System
Glottis Laryngotracheal Adult frog respires by three different types of respiration:
chamber
l Cutaneous respiration : It occurs through the highly vascular skin of frog
Wall of lung
CONCEPT FROG Cavity of lung
Septa
Intact lung
in water or land.
l Buccopharyngeal respiration : It occurs on land or during partial
immersion in water via mucous epithelial lining of buccopharyngeal
MAP
Alveoli
Frog belongs to the Class Amphibia of Phylum Chordata. Frogs are found around ditches, cavity.
ponds, marshes, lakes and streams. They can live in water as well as on land hence called Blood
capillaries l Pulmonary respiration : It is less frequent and takes place through lungs
amphibians. The common Indian frog is Rana tigrina. Fig.: Lungs of frog in adult frog when the frog is outside the water.
Nervous System Olfactory nerve
Morphology Anatomy
l It is highly developed and comprises of:
Olfactory lobe
– Central nervous system (CNS) includes brain and spinal cord. Brain is

Forebrain
covered by two meninges; duramater (outer) and pia-arachnoid (inner).
Anterior Cerebral
Brain is divisible into three parts: Forebrain, midbrain and hindbrain. choroid hemisphere
Circulatory System
l Body of a frog is pointed anteriorly and rounded Spinal cord is located in the vertebral column and joins the medulla plexus
posteriorly. It is slightly flattened dorsoventrally, oblongata via foramen magnum of the cranium (brain case). Pineal body Diencephalon
streamlined to swim through water and divisible into
l
am
Circulatory system of frog is closed and includes heart, arterial – Peripheral nervous system (PNS) includes 10 pairs of cranial nerves Pineal stalk

Midbrain
Optic lobe
system, venous system, blood and lymphatic system. and 9 pairs of spinal nerves . Rarely 10th (paired or unpaired) spinal
head and trunk without neck and tail.
l Skin of frog is thin, moist, smooth, slimy and green
l
gr
Heart is three chambered made up of two anterior atria or auricles
and a single posterior ventricle. Two additional chambers are sinus
nerve is found. Posterior

Hindbrain
Cerebellum
coloured with black or brown spots dorsally and – Autonomic nervous system is made up of sympathetic and choroid
venosus and truncus arteriosus. plexus Medulla
lighter pale yellow ventrally. There are no scales or parasympathetic nerves which controls and coordinates the
l
any other hard exoskeleton parts.
Skin of back has dorsolateral folds or thickenings
l
le
The two auricles, right (larger) and left, are completely separated
from each other by inter-auricular septum. Both auricles open into
l
involuntary activities of the visceral organs.
Five types of sense organs are skin (tangoreceptor), taste buds
oblongata
Spinal cord
l
called dermal plicae.
Head is roughly triangular with a short blunt anterior
snout terminating in a large transverse mouth. It
l Te
single ventricle by a common large auriculo-ventricular aperture
guarded by two pairs of auriculo-ventricular valves.
The inner surface of ventricle has irregular ridges called columnae
carneae or trabeculae, with depressions called fissures.

(gustatoreceptor), nasal chambers (olfactoreceptor), eyes (photoreceptor)

and ears (stato-acoustic organs).
Central canal
Fig.: Dorsal view of brain of frog
bears external nares or nostrils, eyes, brow spot and
Urinogenital System
l
ear drums on the upper side.
Frogs have two large and protruding eyes, having an
almost immovable upper eyelid and a thin semi-
Synangium

Aortic trunks Carotid arch

Systemic arch
Pulmocutaneous arch
Opening leading to

on l
l
In frogs, the excretory and reproductive systems are closely associated, hence they are together called urinogenital system.
Excretory system comprises of kidneys, ureters in females, urinogenital ducts in males, cloaca and urinary bladder. Kidneys
transparent and freely movable lower eyelid. From
lower eyelid arises nictitating membrane that
Right auricle
Wall of truncus
arteriosus
pulmocutaneous arch
Left auricle
e s l
are the chief excretory organs which are made up of large number of uriniferous tubules or nephrons.
From the kidneys, arise ureter in females and urinogenital duct in males.
protects eyes during swimming. Anterior row of Opening of l Cloaca receives faecal matter, genital products and urine (from kidney). Ventrally it is attached to urinary bladder.
l Vocal sacs act as resonators to intensify sound of semilunar valves
Cavum aorticum
pulmonary veins
Sinu-auricular
do l In males, near each kidney there is a cylindrical testis from which several thin vasa efferentia, connecting the testes to
Pylangium

croaking during breeding season. aperture kidneys on each side. The vasa efferentia run transversely through mesorchium and open into the Bidder’s canal which in
Spiral valve Inter-auricular
l Trunk consists of thorax, abdomen and a pair of turn opens into the ureter. Histologically, each testis is a compact mass of seminiferous tubules, the epithelial lining of
Cavum septum
forelimb and hindlimb.
Frog shows sexual dimorphism as male frog
pulmocutaneum Auriculo ly which produces sperms. The sperms when mature are dropped into the lumen to pass into the ureter through vasa
l
possesses developed vocal sacs and nuptial pad
during breeding season and their body is somewhat
slender and darker in colour than female frog.

Posterior row of
semilunar valves
ventricular valve
Chordae tendineae
Fissures

ai l
efferentia and Bidder’s canal.
Females have two ovaries where ova are produced by ovarian follicles. On each side of an ovary is an oviduct which starts
posteriorly and forms uterus, which opens into the cloaca. During breeding season ova are released into the coelom and
then they reach the ovarian funnels from where they pass to the ovisacs, cloaca and then outside.
External nares Nictitating membrane

D l Egg of frog is telolecithal.

Ka
Columnae carneae Part of oesophagus
(for respiration) (protects the eye during Cystic duct Oesophagus Ostium
Eye swimming and keeps Wall of ventricle
Right lobe Ovarian funnel
it moist in air) Left lobe of liver Fat body
Head Tympanum (receives Fig.: Internal structure of heart of frog (ventral view) of liver
Bile duct
sound waves) Gall bladder Testis
Digits
Manus
Digestive System
T Pancreatic ducts
Pancreas
Mesorchium
Forelimb
Trunk

Antebrachium
Brachium
Dorsolateral
dermal plicae

l
l

The digestive system mainly consists of alimentary canal and its

associated glands.
Mouth leads into a buccopharyngeal cavity which opens into
Mesentery EE
Stomach
Hepatopancreatic
duct

Adrenal gland
Left kidney

Fat body
Ovary
Ovarian tube
Thigh
Anus l
oesophagus through gullet.
Stomach is situated behind the oesophagus and divisible into
Pyloric constriction
Duodenum
Ileum
N Urinogenital duct
(carries urine
and sperm)
Kidney
Adrenal gland
cardiac stomach and pyloric stomach. Spleen Part of
Hindlimb rectum Seminal vesicle
l The small intestine is divisible into an anterior duodenum and a Ureter
Crus (shank ) Rectum (carries urine)
posterior ileum. Digestion of food and absorption of digested food Urinary bladder
Urinary Ovisac
Pes (foot) Toes occur in the small intestine. Cloaca bladder Cloacal chamber
l Ileum leads to rectum or large intestine. The rectum opens into the Cloacal chamber
Cloacal aperture Urinary
cloaca through the anus. bladder
l Digestive glands of frog include liver, pancreas, gastric glands and Cloacal aperture Cloacal aperture
Web Fig.: Alimentary canal (except
Fig.: Dorsal view of frog intestinal glands.
buccopharyngeal cavity) of frog Fig.: Urinogenital system of male frog Fig.: Urinogenital system of female frog
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 CONCEPT PHYTOHORMONES
MAP Phytohormones refer to a chemical substances other than nutrient molecules produced naturally in
plants. They may be translocated to another region and are capable of regulating one or more
physiological reactions, when present in low concentrations.

PHYTOHORMONES
Plant growth regulators or hormones are broadly classified into two categories.

Auxin Ethylene
Nature: Weakly acidic growth hormone having an unsaturated ring structure. Auxins refer to natural (IAA, PAA, IAN) and Nature: It is the only gaseous phytohormone which
synthetic (Indole 3-butyric acid, NAA, 2, 4-D, 2, 4, 5-T) compounds having similar structure and properties. stimulates transverse or isodiametric growth but
Discovery: Darwin (1880) was first to find sensation of unilateral illumination in the coleoptile tip of canary grass. Later retards the longitudinal one.
Kogl and Smith (1931) isolated three chemicals from human urine which they named as auxin a , auxin b and hetero Discovery: R. Gane (1934) found that H H
auxin. IAA is the universal natural auxin. substance causing ripening was C C
Location: It is found in shoot apices, leaf primordia and developing seeds and is synthesised from amino acid tryptophan, ethylene. But it was recognised as a H H
a precursor of IAA or auxins. plant hormone by Crocker et al (1935).
Bioassay: Avena curvature test and root growth inhibition test are done for examining auxin effect. Location: It is found in almost all parts of plants in
minimal amount but maximum production occurs
Physiological functions:
during ripening of fruits and in tissues undergoing
l Promotes cell enlargement and division and initiates root formation on stem
CH2COOH senescence. It is synthesised from amino acid
cuttings.
methionine in plants.
l Cambial activity and xylem differentiation is also regulated by auxins.
Bioassay: The 'triple response' of etiolated pea plant
l Shows apical dominance i.e., inhibits the growth of lateral buds. N and gas chromatographic assay are used as bioassays.
l Prevents or delays abscission as well as induces synthesis of ethylene.
H
Physiological functions:
INDOLE-ACETIC ACID
l Produces tropic plant responses like phototropism and geotropism. l Promotes apical dominance and prolongs dormancy
(IAA)

m
l Shows feminising effect on some plants.
of lateral buds but breaks the dormancy of buds,
seeds and storage organs.
Commercial uses: l Induces abscission and senescence of various parts

a
l In tissue and organ culture to form callus and initiate rooting. i.e., leaves, flowers and fruits etc.

gr
l To produce parthenocarpic fruits. l Induces epinasty, a phenomenon which decreases

l Auxins like 2, 4-D and 2, 4, 5-T acts as weedicides by being selectively harmful to broad leaved dicot weeds.
the sensitivity to gravity.
l Helps in root initiation, growth of lateral roots and

le
l Induces flowering in litchi and pineapple.
root hairs.
l NAA increases the number of dwarf shoots and fruits on them.
l Stimulates flowering in pineapple and other related

Te
l Prevents pre-harvest fruit drop of orange and apple (by low concentration of 2, 4-D) and tomato (by NAA)
plants and helps in synchronising fruit set.
l Induces ripening of fleshy climacteric fruits and

Gibberellin dehiscence of dry fruits.

on
Nature: Weakly acidic growth hormone having gibbane ring structure. Commercial uses:
O
Growth Promoting Hormones

l Ethylene lamps are used for ripening of fleshy fruits

Growth Inhibiting Hormones

Discovery: Hori and Kurosawa discovered the active substance from filtrate
of fungus, Gibberella fujikuroi (causing bakane disease in rice plants) and e.g., banana, mango, apple, tomato.
named it gibberellin. GA3 was first gibberellin to be isolated in its pure form CO l Ethylene is used to induce feminising effect e.g.,
e

and remains the most extensively studied. number of female flowers and thus fruits in
OH
s

cucumber.
Location: The major sites of gibberellin production in plants are embryos, HO
do

CH COOH l Ethylene also permits thinning of excess flowers

roots and young leaves near the shoot tip. Mevalonic acid (derived from 3 CH2
and young fruits so as to allow better growth of
acetyl Co-A) acts as precursor for synthesis of gibberellins. It is transported remaining fruits.
through simple diffusion as well as via conducting channels.
Bioassay: Barley endosperm test and germination of dwarf pea seeds are used as bioassays.
ly

Abscisic Acid
Physiological functions:
Nature: It is a mildly acidic growth hormone which acts
ai

l Stimulates stem elongation and leaf expansion.

as a general growth inhibitor. It is also called as stress
l Overcome natural dormancy of buds, tubers, seeds etc. hormone since its production is stimulated under
D

l Induces elongation of reduced stem or bolting in rosette plants e.g., henbane, cabbage. conditions of drought, water logging and adverse
environmental conditions.
l Promotes seed germination by inducing production of hydrolytic enzymes for solubilising reserve food.
Ka

l Promotes flowering in long day plants during non-inductive period.

H trans CH3 cis
l Controls fruit growth and development as well as induces parthenocarpy.
l Promotes formation of male flowers on female plants e.g., Cannabis. They can also replace female flowers with male H3C CH3 C
C C
ones on monoecious plants of cucurbits. 6 5 C 3 H
2
T

5 4
1 OH
Commercial uses: H 1COOH
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l Exogenous application of GA4 and GA7 mixture to increase the number and size of fruits e.g., apple, grapes, tomato. 4 2
O 3 CH3
l Production of seedless pomaceous fruits by parthenocarpy.
l GA7 delays senescence of fruits and delays its ripening thus, extending its shelf life and storage period.
Discovery: The hormone was first isolated by Addicott
N

l Induces offseason flowering in many long day plants as well as those requiring vernalisation.
et al (1963) from cotton bolls.
l Application of gibberellins increases length of stem and yield of sugarcane.
Location: It is found in many parts of the plant but is
l Promotes early maturity resulting in seed production in juvenile conifers. more abundant in chloroplast of green cells. It is
synthesised from mevalonic acid or xanthophyll.
Bioassay: Rice seedling growth inhibition test and
Cytokinin inhibition of a-amylase synthesis in barley endosperm
are used as bioassay.
Nature: These are basic hormones, being derivatives of either aminopurine or phenyl urea that promote cytokinesis.
Physiological functions:
Discovery: The first cytokinin was discovered from autoclaved herring sperm DNA which stimulated cell division in l Induces dormancy of buds, seeds and underground
tobacco pith cells. It is called kinetin and does not occur naturally in plants. stems, hence also called as dormin.
CH2OH
The first natural cytokinin was obtained from unripe maize grains, called zeatin CH2 C l Promotes abscission of flowers and fruits.
(6-hydroxy 3-methyl trans 2-butenyl amino purine). NH CH CH3 l Induces senescence of leaves by promoting
It is found in coconut milk. degradation of chlorophyll and proteins.
Location: It is mainly found in roots, however it is also synthesised in endosperm regions N N l Stops cambium activity (in vascular cambium)
of seeds, growing embryos, young fruits and developing shoot buds. towards the approach of winter.
N
Bioassay: Tobacco pith culture, retardation of leaf senescence and excised radish N H l Inhibits seed germination by inhibiting gibberellin
cotyledon expansion are used as bioassays for cytokinins. Zeatin mediated amylase formation.
Physiological functions: l It is antagonist to gibberellin and counteracts the

l Promotes cell division.

effect of growth promoting hormones-auxins and
cytokinins.
l Essential for morphogenesis and differentiation of tissues and organs.
Commercial uses:
l Delays senescence by mobilisation of nutrients.
l Used as antitranspirant (as application of even
l Overcome apical dominance caused by auxins and promote lateral bud development.
minute quantities of ABA on leaves causes partial
l Induces accumulation of salts inside cells and help in phloem transport. closure of stomata), thus, preventing transpiration
l Promotes femaleness in flowers. as well as reducing photosynthesis.
l Induces flowering in some short day plants, even
Commercial uses:
under unfavourable photoperiods.
l Forms essential component of tissue culture as required for morphogenesis.
l External application on stem cuttings initiate
l Application of cytokinin increases the shelf life of flowers and vegetables, keeping them fresh for longer periods. rooting.
l Helps in developing resistance to pathogens and extremes of temperature, in plants. l Induces parthenocarpic development in rose.
l Delays senescence of intact plant parts. l Used in prolonging dormancy of buds, storage
organs and seeds.
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 Human skeleton constitutes the rigid framework of connected

CONCEPT HUMAN SKELETON

bones that gives shape to the body, protects and supports its

MAP
soft organs and tissues and provides attachments for muscles.
Human skeleton is made up of 206 bones (300 bones in
newborns) which are distributed into axial and appendicular
skeleton.

AXIAL SKELETON APPENDICULAR SKELETON

· It lies along the longitudinal axis of the body; supports and protects the organs of the · It is situated at the lateral sides which actually extend outwards from the principal axis.
head, neck and trunk. · It consists of two girdles, the pectoral and pelvic girdles and the bones of arms and
· It includes skull, vertebral column, sternum and ribs . legs.

SKULL PECTORAL GIRDLE

Parietal Manubrium of sternum Coracoid
Frontal bone bone · Skull is the bony framework of the head. · Each pectoral girdle consists of two bones : 1 Clavicle process
· It consists of 29 bones, separated by sutures. These bones clavicle and 1 scapula. The scapula (shoulder
Nasal bone are cranial bones (8 flattened bones forming the brain blade) consists of a sharp ridge, the spine and a Pectoral Girdle
triangular body. The end of the spine projects as a (Shoulder Girdle)
Zygomatic box or cranium), facial bones (14 bones forming the front

m
bone part of the skull), hyoid bone (single bone forming floor of flattened and expanded process called acromion.
Maxilla the buccal cavity) and bones of middle ear (3 small bones This process articulates with the clavicle. Acromion
Scapula
in each ear, namely malleus, incus and stapes). · At the lateral end of the superior of the scapula is a process

a
Occipital
bone · The bones of cranium are : 1 frontal bone, 2 parietal bones, projection of the anterior surface called the coracoid

gr
Mandible
Mastoid
Temporal
2 temporal bones, 1 occipital bone, 1 sphenoid bone and process, to which the tendons of the muscles
bone
process
1 ethmoid bone. attach. At the point where the superior and
lateral borders of the scapula meet there is the lateral angle which

le
· Temporal bone has a projection called mastoid
process. Cranium presents a shallow articular surface termed as glenoid cavity into
which the head of the humerus is articulated.

Te
· The cranium has two small protuberances at the Skull
· The primary function of the pectoral girdle is to provide an
posterior end called occipital condyles, that articulate with the first vertebra (atlas
Facial bones attachment point for the numerous muscles that allow the shoulder
vertebra), thus, human skull is dicondylic.
and elbow joints to move.
· 14 bones form the skeleton of face viz. 2 zygomatic, 2 maxilla, 2 nasal, 2 Clavicle
on
lacrimal, 1 vomer, 2 palatine, 2 inferior nasal conchae and 1 mandible.
Ribs
· Hyoid is a u-shaped bone which attaches tongue with the floor of buccal Cervical
cavity. It does not articulate with any other bone. vertebra
· A large hole called foramen magnum at the base of skull allows the
FORELIMBS
e

brain to continue into the spinal cord located in the backbone. Scapula
· Each arm has 30 bones, which constitute 1 humerus (upper arm), 1
s

· Skull protects our brain; it bears jaws which help in mastication of food, Sternum radius and 1 ulna (lower arm), 8 carpals (wrist),
do

etc. 5 metacarpals (palm) and 14 phalanges (digits).

Humerus · The humerus is the longest bone in the upper extremity.
VERTEBRAL COLUMN Xiphoid · At the bottom of the humerus, are two depressions where it
process of connects to the ulna and radius of the forearm.
ly

7 Cervical vertebrae · It is also called backbone or spine. It sternum · Together, the humerus and the ulna make up the elbow, ulna is
(neck backbones) is curved, vertical rod, about 70 cm
longer than the radius. Radius, however, contributes more to the
ai

long, in the mid-dorsal line of the Radius movement of the wrist and hand than the ulna.
neck and trunk. It consists of 33
12 Thoracic vertebrae Ulna · Each wrist is composed of eight carpals which are
D

(chest backbones) vertebrae. However it consists of 26

Coccyx arranged in two rows : scaphoid, lunate, triquetrum and
bones, because five sacral vertebrae
Pubis pisiform in proximal row and trapezium, trapezoid,
are fused to form one sacrum and
capitate and hamate in distal row.
Ka

Intervertebral disc four coccygeal vertebrae are fused to

form one coccyx. Carpals · The forelimbs give support to the shoulders by articulating
Ischium Metacarpals the head of the humerus with the glenoid cavity of the
5 Lumbar vertebrae · A typical vertebra has a large, disc-like
(lower backbones) anterior, flattened portion, the Phalanges pectoral girdle.
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Sacrum (5 fused
centrum or body and a posterior Femur
pelvis backbones) portion, the neural arch.. The latter
EE

Coccyx encloses the spinal cord. The hole formed Ilium PELVIC GIRDLE
by the neural arch is the vertebral
foramen. The vertebral foramina of all Lumbar · The pelvic girdle
girdle, also
twenty four vertebrae form the vertebral canal or neural canal. vertebra Patella called the hip girdle, is
N

Sacrum
· Vertebrae are categorised into five groups: cervical (7), thoracic (12), composed of two coxal
lumbar (5), sacral (5) and coccygeal (4). (hip) bones. Ilium

· Vertebral column displays four curves to enhance balancing powers and firmness for · The coxal bones are also
called the ossa coxae or Coccyx
upright posture of the body. These curvatures are cervical, thoracic, lumbar and pelvic Fibula Pubis Acetabulum
(=sacral). innominate bones. Ischium
· Each coxal bone consists Pubic
· Between the centre of adjacent vertebrae there are elastic pads of fibrocartilage, the Tibia Pubic arch symphysis
intervertebral discs which provide mobility to the vertebrae, check undue frictions and of three separate parts :
take up shocks. the ilium (short and
Tarsals
· Vertebral column carries the weight of the body in motion and when the organism is standing. straight bone), the ischium (lower elongated bone, running parallel to
Metatarsals vertebral column) and the pubis (inner, smaller bone).
STERNUM Phalanges · On its outer surface it has a deep depression called the acetabulum which,
Clavicular
with almost spherical head of the femur, forms the hip joint.
· This is a flat bone which is present just under the
notch · It supports the weight of the body from the vertebral column. It also protects
Manubrium skin in the middle of the front of the chest. It is about
and supports the lower organs, including the urinary bladder, the
Sternal 15 cm long.
angle reproductive organs, and the developing foetus in case of a pregnant
Facets for · Its shape is like a dagger and consists of three parts—the woman.
attachment
Body of ribs 1-7 manubrium is the uppermost part, the body is the middle portion
and the xiphoid process is the tip of the bone.
· The true ribs (7 pairs) are attached to the sternum. HINDLIMBS
Xiphoid
process · It protects the internal organs in the thoracic region and helps in the · Each leg has 30 bones which constitute 1 femur, 1 patella, 1 tibia, 1 fibula, 7 tarsals, 5
respiratory mechanism. metatarsals and 14 phalanges.
· Femur, tibia and fibula bones together support the shank of the leg. The tarsals form the
RIBS ankle, metatarsals form the sole and phalanges form the digits of the foot.
· The ribs are thin, flat, curved bones that form a protective cage around the organs in the upper body. · The femur is the longest, largest, and strongest bone in the body whose head fits into the
· Ribs comprise of 24 bones arranged in 12 pairs. Each rib remains attached to the respective thoracic acetabulum of hip girdle.
vertebra. · The tibia connects to the femur to form the knee joint and with the talus, a foot bone, to
· The first seven pairs of ribs are attached directly with the sternum and are called true ribs. The 8th, 9th and allow the ankle to flex and extend.
10th pairs of ribs do not articulate directly with sternum, but join the seventh rib by hyaline cartilage. These · The tibia is larger than the fibula because it bears most of the weight, while the fibula
are called vertebrochondral ribs or false ribs. The last two (11th and 12th) pairs of ribs remain free serves as an area for muscle attachment.
anteriorly and are not attached either to sternum or cartilage of another rib, and are called floating ribs. · Fibula is shorter, thinner and slender.
· A typical rib consists of 2 parts : vertebral and sternal. The vertebral part is long and bony. It articulates with · Each ankle is composed of seven tarsals which are calcaneum, talus, cuboid, navicular
the thoracic vertebrae. and first, second, third cuneiforms.
· The sternal part is short and cartilaginous. It articulates with the sternum or sternal part of its upper rib. · The leg bones carry the weight of the body and are involved in propulsion and support.
CONCEPT SYNAPSE
MAP
Synapse is an anatomically specialised junction between two neurons, where the axon (or some
other portion) of one cell (neuron) terminates on the dendrites or some other portion of another
cell. The term 'synapse' was first introduced by Charles Sherrington (1924). Transmission of nerve
impulse takes place across a synapse between neurons or neurons and an effector. The neuron
which sends messages is called presynaptic cell whereas the neuron which receives messages is
postsynaptic neuron.
Sending neuron
Receiving
neuron
STRUCTURE OF SYNAPSE
Most of the synapses comprise the following structures:
(i) Synaptic knob – Terminal bulbous ending of presynaptic axon which is devoid of neurofilaments but its
Sending
cytoplasm contains: neuron
(a) Synaptic vesicles – Small vesicles present in presynaptic cytoplasm that contain neurotransmitters
(for excitation or inhibition), like acetylcholine, GABA, etc. Action
(b) Mitochondria, ER and microtubules. potential
(c) Presynaptic membrane – Nerve membrane which is in close approximation with membrane of
Vesicle containing
postsynaptic cell. neurotransmitters
(ii) Sub-synaptic and postsynaptic membrane – The surface of the cell membrane involved in the
synapse is called the sub-synaptic membrane and the remaining of the motor neuron cell membrane is
Synaptic gap Axon terminal
called the postsynaptic membrane. Receptor sites for neurotransmitters are usually located on the sub-
synaptic membrane. Presynaptic membrane

Postsynaptic
TYPES OF SYNAPSE
Receptor sites on
membrane
receiving neuron
Neurotransmitter
On
the

m
On th ion wi
locat

b asi
so
Chemical Synapse
e b thin

fp

a
hy
asi

s l Signals are transmitted across synaptic cleft in form

s o ne

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of chemical messenger – a neurotransmitter,
io
fp r

lo
ox
released from presynaptic axon terminal.
g
vo imi Axo-dendritic Synapse
r

y
us t y a Chemical synapse operates only in one direction, as
sys nd Synapse between fine terminal l

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tem neurotransmitter is stored on the presynaptic side
branches of axon of one neuron and
dendrites or cell body of another of synaptic cleft, whereas receptors for neuro-

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Axo-dendritic
synapse neuron. It is located in motor neurons transmitters are on postsynaptic side.
in spinal cord, excitatory synapse in
Axo-axonal the cerebral cortex, etc. Electrical Synapse Chemical Synapse
Presynaptic
synapse
neuron
on
Microtubule
Axo-axonal Synapse Dendrite Presynaptic
Synapse between axons of Cytoplasm Synaptic vesicle
neuron
two neurons. It is present in
Mitochondrion
e

spinal cord.
s
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Myelin
Axon
Postsynaptic Postsynaptic
Gap
neuron neuron
junction
Ions flow through gap Synaptic Neurotransmitter released
Presynaptic junction channels
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Dendro-dendritic membrane vesicle fusing Presynaptic membrane

synapse Axo-somatic
synapse
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Synaptic
cleft

Dendro-dendritic Synapse Axo-somatic Synapse

D

l Synapse between dendrites of Synapse between axon of one Postsynaptic

Postsynaptic neurotransmitter Ions flow through Postsynaptic
two neurons, but is rare. It is neuron and soma of another membrane
Gap junction channels
receptor postsynaptic channels membrane
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present between mitral and neuron. It is present in motor

granule cell in the bulb. neurons in spinal cord and
autonomic ganglia. Electrical Synapse
l Here pre-and postsynaptic membrane are joined by gap
T

junctions, through which ions can pass easily.

Impulse transmission across electrical synapse is faster than
EE

l
chemical synapse because of the direct flow of electrical
current from one neuron to another through gap junction,
MECHANISM OF IMPULSE CONDUCTION
N

At Electrical
PROPERTIES OF SYNAPSE Synapse
l Gap junctions in electrical
synapse allow the local currents
l Convergence and Divergence : Many presynaptic resulting from arriving action potentials
neurons converge on any single postsynaptic neuron, At Chemical to flow directly across the junction from
e.g., in spinal motor neurons, some inputs come from Synapse one neuron to the other.
dorsal root, some from long descending spinal tracts l This depolarises the membrane of
Mechanism of chemical transmission across a
and many from interconnecting neurons. The axons of the second neuron to threshold,
synapse is as follows:
most presynaptic neurons divide into many branches continuing the propagation of
that diverge to end on many postsynaptic neurons. Action potential arrives at axon terminal the action potential.
l Fatigue : Repeated stimulation of presynaptic neuron
leads to gradual decrease and finally disappearance of Voltage gated Ca2+ ion channels open and electrochemical
the postsynaptic response. This is due to exhaustion of gradient favours influx of Ca2+ and Ca2+ flows into axon terminal
chemical transmitter, as its synthesis is not as rapid as
the release. Ca2+ ions cause synaptic vesicles to move to the
l Synaptic Delay : When an impulse reaches the surface of the knob and fuse with synaptic membrane terminal
presynaptic terminal, there is a gap of about 0.5 msec.,
before a response is obtained in postsynaptic neuron. Vesicles release neurotransmitters by exocytosis
This is due to the time taken by synaptic mediator to be
released and to act on postsynaptic membrane.
Neurotransmitters diffuse across synaptic cleft and bind to
l Synaptic Plasticity : Plasticity implies the capability of
receptors on postsynaptic membrane
being easily moulded or changed. Synaptic conduction
thus can be increased or decreased on the basis of past
experience. These changes can be presynaptic or This causes depolarisation and generation of
postsynaptic in location and play an important role in action potential in the postsynaptic
learning and memory. membrane.
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 CONCEPT ASEXUAL REPRODUCTION
MAP
Life cannot be created de novo rather it arises from pre-existing life. Reproduction is the only method by which continuity of life
is maintained. It is of two types: asexual and sexual. Asexual reproduction is the formation of new individual without involving
fusion of gametes. It is uniparental as offspring are produced by a single parent.

Fission
l It is a type of asexual reproduction in which
CHARACTERISTICS OF ASEXUAL REPRODUCTION
the parent organism divides into two or
more daughter cells. l It is more primitive than sexual reproduction as it involves only mitotic divisions.
l In this type of reproduction, whole parent l New organisms are produced from the somatic part of parental organism, so it is also called as
body acts as the reproductive unit. (a) somatogenic reproduction.
l It is of three types: l New individuals produced are genetically similar to the parent as well as to each other and are called
(a) Binary fission : In this, parent organism clones. Hence, it plays no role in evolution.
divides into two halves, each half forming l Unit of reproduction may be either whole parent body, or a bud, or a body fragment, or a single
an independent daughter organism. It can somatic cell.
be simple (occurs through any plane, e.g., (b) l It is usually found in lower organisms like protistan protozoans (Amoeba, Paramecium), sponges
Amoeba), longitudinal (plane of division is
longitudinal axis of body, e.g., Euglena), (Scypha), coelenterates, (Hydra, Tubularia, etc.), certain flatworms (Planaria), some worms and
transverse (plane of division runs along tunicates (Salpa, Ascidia, etc.). It is absent in higher invertebrates and all vertebrates.
transverse axis of body, e.g., Paramecium)
and oblique (plane of division is oblique, Regeneration
e.g., Ceratium).
(c)
(b) Multiple fission : In this process, parent l It refers to the growth of new tissues
body divides into many similar daughter Fig.: Binary fission in (a) Amoeba
(b) Euglena (c) Paramecium or organs to replace lost or

m
organisms. It occurs during unfavourable
damaged part.
conditions. Nucleus of the parent divides
by repeated amitosis into many nuclei which eventually form several daughter l Regeneration is of two types:

a
cells. E.g., Amoeba, Plasmodium (malarial parasite). morphallaxis (formation of whole

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(c) Plasmotomy-Division of multinucleate parent into many multinucleate body from a fragment) and
daughter individuals without division of nuclei. Nuclear division occurs later to
epimorphosis (replacement of lost
maintain number of nuclei. E.g., Opalina, Pelomyxa.

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parts). It can be reparative
Cyst wall Daughter Pseudopodiospores Young Amoeba (regeneration of damaged tissue (i) (ii) (iii)

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nuclei
only) or restorative (redevelopment (a)
of severed body part). In epimor-
phosis, a mass of undifferentiated
cell referred to as blastema is formed
on
Daughter nuclei (a) Daughter cells released
after wound healing and then the 1 2 3 4 5
blastema cells actively proliferate to
Intact Amputation Wound Blastema Blastema cell Patterning new Newly
restore the lost part of the limb healing formation proliferation limb tissue regenerated
e

limb
amputated organ. (b)
Schizont Crypto Merozoites
s

(b) merozoite l Regeneration is found in Hydra, Fig.: (a) Regeneration in (i) Planaria (ii) Hydra (iii) Starfish
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Fig.: Multiple fission (a) Amoeba (b) Malarial parasite starfish, Planaria, etc. (b) Epimorphosis
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Budding Sporulation
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l Budding refers to the process of formation of daughter l Spores are minute, single celled, thin or thick walled
individuals from a small projection or bud arising on the propagules which are dispersive structures released from
parent body. the parent body and form new individuals. Spore formation
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l Each bud enlarges, develops parental characters and TYPES OF is common in members of monera, protista, algae and fungi.
separates to lead an independent life. Some of the commonly produced spores are:
l Budding can be either exogenous (formed on the outer surface) ASEXUAL (a) Zoospores : Motile and flagellated spores produced inside
e.g., Hydra, yeast or endogenous (formed inside
REPRODUCTION zoosporangia. Flagella help in proper dispersal in aquatic
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parent body) e.g., Spongilla. In Spongilla, bud is called a gemmule.

habitat. E.g., algae and lower fungi like Phycomycetes.
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(b) Conidia : Non-motile spores produced singly or in chains by

Tentacles constriction at the tip or lateral side of special hyphal
branches called conidiophores. These are dispersed by wind
and germinate to form new individuals. E.g., Penicillium.
N

(c) Chlamydospores : Thick walled spores produced directly

from hyphal cells. May be terminal or intercalary in position
and capable of withstanding unfavourable conditions. E.g.,
Rhizopus.
A projection grows on Bud grows Splits away from parent Fragmentation (d) Oidia : Small fragments of hyphae that are thin walled and
outer surface of body. externally. and grows independently. do not store reserve food material. Oidia give rise to new
l In this type of reproduction, parent body breaks into
hyphae. These are formed under conditions of excess water,
two or more pieces called fragments.
(a) Nuclear division Bud sugar and certain salts. E.g., Agaricus.
l Each fragment develops into a new organism.
(e) Sporangiospores : Non-motile spores produced inside
Developing l In fragmentation, rate of reproduction is high.
sporangia. Usually get dispersed by wind and germinate to
bud l It occurs in flatworms, sea anemones, coelenterates,
form new mycelium. E.g., Rhizopus, Mucor.
echinoderms, algae like Spirogyra, etc.

Zoospores Chains of conidia

Flagella Conidia
(b) Chloroplast
Mother cell
Nucleus
Micropyle
(Pore through which
Monaxon archaeocytes come out and Zoosporangium Germinating
spicules form new colony) (Parent cell) Conidio- conidium
Septa
Outer membrane phore (b)
(a)
Archaeocytes Sporangium Sporangio-
spores
(Small group of
cells enclosed by Oidia
protective coat) Columella
Spiral
Chlamydospores Dehisced
chloroplast Sporangio- sporangium
Hyphae phore
Inner membrane
Stolon
(e) Rhizoidal
(c) (c) (d) hyphae
Fig.: (a) Exogenous budding in Hydra (b) Exogenous budding Fig.: Various types of spores (a) Zoospores (b) Conidia
in yeast (c) Endogenous budding (gemmule) in Spongilla Fig.: Fragmentation in Spirogyra (c) Chlamydospores (d) Oidia (e) Sporangiospores
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Type of Germ Type of

Chromosomes
cells Division
No.
Oogonium Mitosis
Multiplication 46
Chromosomes Type of Germ cells Type of Division
N

(2n)
Phase
No.
Spermatogonium Mitosis
Multiplication 46 Additional
(2n)
Phase oogonia (2n)
Growth Phase
Primary 46 Primary
Growth Phase 46 Additional oocyte (2n)
spermatocyte (2n) spermatogonia (2n)
Meiosis I Meiosis I
23 Secondary
spermatocytes (n) Secondary
Maturation Phase 23 First polar
Meiosis II body (n) oocyte (n)
Spermatids Sperm (n)
23 (n) Maturation Phase
Meiosis II
Second polar Male pronucleus
Spermatozoa 23 Mature
bodies (n)
Spermiogenesis (sperms) (n) ovum (n)
23 (All degenerate)
Female pronucleus
Fig.: Stages in spermatogenesis (diagrammatic) Fig.: Stages in oogenesis (diagrammatic)

Inhibits Hypothalamus
GnRH Hypothalamus
and LH GnRH
production Anterior pituitary GnRH
LH Testis FSH Positive Anterior pituitary Negative
Leydig’s cells Sertoli cells feedback feedback
LH/FSH
Testosterone Ovary
Stimulates
Spermato- Estrogen and
Positive Testosterone genesis
Progesterone
feedback
Negative Reproductive tract Inhibin Uterus
feedback and other organs
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 CONCEPT TRANSLATION Translational Machinery

MAP
Ÿ Basic translational machinery is same in eukaryotes and
Translation is the process by which a protein or polypeptide is prokaryotes, however few differences occur. It is composed of
synthesised inside the living cell using mRNA as a template. This five components, i.e., mRNA, tRNA, amino acid, enzymes
biochemical process is called translation because the information (aminoacyl tRNA synthetase, peptidyl transferase) and ribosome.
present in the form of four letter alphabet of nucleic acid is Ÿ In eukaryotes, each mRNA is monocistronic (encodes for only
translated into twenty letter alphabets of proteins. one polypeptide) whereas in prokaryotes, many mRNAs are
polycistronic (encodes for two or more different polypeptides).
Ÿ Ribosome is the site of protein synthesis. 70S (30S + 50S)
MECHANISM OF TRANSLATION ribosomes are involved in prokaryotic translation while 80S
Ÿ The steps of translation are common in both prokaryotes and eukaryotes. Three main steps involved in (40S + 60S) ribosomes are involved in eukaryotic translation. The
translation are initiation, elongation and termination. Before initiation amino acids are activated and attached two subunits of ribosomes associate at the time of protein
to tRNAs in two steps called activation of amino acids and charging or aminoacylation of tRNA respectively. synthesis and then separate after the completion of process.
Ÿ In eukaryotes, the initiating amino acid is methionine, not N-formylmethionine (fMet) as in prokaryotes. Ribosomes have three sites; the peptidyl (P) site, aminoacyl (A)
Ÿ The main difference between initiation of translation in prokaryotes and eukaryotes is that in bacteria, a Shine- site and exit (E) site. Eukaryotic ribosomes do not have E-site.
Dalgarno sequence (4 to 9 purine residues, 8 to 13 base pairs to the 5’ side of initiation codon) guides correct Ÿ tRNAs pick up particular amino acids (at CCA or 3’ end) and take
initiation codon (5’ AUG) and is the binding site for the 30S ribosomal subunit. the same to mRNA over particular codons corresponding to their
Ÿ In contrast, most eukaryotic mRNAs do not contain Shine-Dalgarno sequences. Instead, a 40S ribosomal anticodons. Each tRNA contact with ribosome at T y C loop and
subunit attaches at the 5’ end of the mRNA and moves downstream (i.e., in a 5’ to 3’ direction) until it finds the the enzyme aminoacyl tRNA synthetase at DHU loop. Eukaryotic
AUG initiation codon. This process is called scanning. mRNAs have 5’ - cap and poly A tail at 3’ end.

1
Activation of amino acid and Charging of tRNA Eukaryotes
Ÿ Amino acids are activated by activating enzymes, aminoacyl tRNA synthetases in presence of ATP to produce 2
aminoacyl-adenylate-enzyme complex. Initiation
Mg2+ Ÿ Eukaryotic cells have atleast nine initiation factors, i.e., eIF2, eIF2B,
AA + ATP + Enzyme AA ~ AMP – E + PPi eIF3, eIF4A, eIF4B, eIF4E, eIF4G, eIF5 and eIF6.
Amino Aminoacyl-adenylate
acid enzyme-complex Ÿ The first step is the formation of a pre-initiation complex
This complex reacts with tRNA specific for the amino acid. Amino acid links to 3’ - OH end of tRNA through consisting of the 40S small ribosomal subunit, Met-tRNAiMet , eIF2

m
Ÿ
and GTP;
its - COOH group to form aminoacyl tRNA complex.
Ÿ The pre-initiation complex now binds to the 5’ end of the eukaryotic
AA ~ AMP – E + tRNA ® AA – tRNA + AMP + E

a
Charged mRNA, a step that requires eIF4F complex (eIF4A, eIF4E, eIF4G, also
Aminoacyl adenylate
tRNA called cap binding complex) and eIF3. Thus, this complex intact

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enzyme
both the 5’ and 3’ ends of the mRNA.
Ÿ The eIF4A is a RNA helicase that unwinds any secondary structure of

le
mRNA, preparing it for translation.
2
Prokaryotes Ÿ The complex now moves along the mRNA in a 5’ to 3’ direction until it

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Approaching 50S locates the AUG initiation codon (i.e., scanning of mRNA).
Initiation subunit to form 70S Ÿ Once the complex is positioned over the initiation codon, the 60S
50S
Ÿ 3 initiation factors are required i.e., IF1, initiation complex large ribosomal subunit binds to form an 80S initiation complex, a
IF2 and IF3. step that requires the hydrolysis of GTP and leads to the release of
Initiation begins with the binding of IF1
on
Ÿ fMet several initiation factors.
and IF3 to the small (30S) ribosomal

eIF3, 1, 1A
subunit.
Ÿ The small subunit then binds to the GTP
eIF4B eIF5
e

mRNA via complementary pyrimidine IF2 eIF4E

5’ UA C 3’ Met
rich sequences close to 3’ end of 16S rRNA mRNA 4G, 4A eIF2
s

AUGUUUGGC CUUGCUA C C GCUU

guided by Shine-Dalgarno sequence and 30S Cap
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moves 3’ along the mRNA until it locates AUG

IF1 IF3
the AUG initiation codon. 40S
Ÿ The initiator tRNA charged with N-
formlymethionine and a complex of IF2 eIF4E
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4G, 4A
and GTP (fMet-tRNAfMet/IF2/GTP) now binds to mRNA and 30S subunit. eIF4B
Ÿ The complex of mRNA, fMet-tRNAfMet, IF1, IF2 and the 30S ribosomal subunit is called the 30S initiation complex. eIF3, 1, 1A Met
ai

Ÿ Structural changes then lead to the ejection of IF1 and IF3 and IF2 now stimulates the association of 50S eIF2 eIF5
subunit of ribosomes. Simultaneously, the GTP bound to IF2 is hydrolysed to GDP and Pi and leading to
D

release of IF2. This forms 70S initiation complex. Cap AUG

Ÿ When this complex is formed, the ribosome is ready for the elongation phase.
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3 3
Elongation A. Elongation
Charged tRNA
Ÿ Elongation requires three factors, i.e., Ÿ The elongation stage of translation in
T

EF – Tu, EF – Ts and EF – G and enzyme eukaryotes is quite similar to the prokaryotes.

peptidyl transferase. Ÿ It requires three elongation factors, eEF1a,
EE

Ÿ The fMet-tRNAfMet occupies the P site E eEF1bg and eEF2 as counterparts of prokaryotic
site 3’ EF – Tu, EF – Ts and EF – G respectively.
and another aminoacyl tRNA complex
Ribosome ready for mRNA
(aminoacyl tRNA – EF – Tu – GTP) reach at Ÿ The GTP form of EF1a delivers aminoacyl tRNA to
next aminoacyl tRNA P A
A site depending upon the anticodon site site the A site of the ribosome and EF1bg catalyses the
N

5’ 2 GTP Peptide
present on mRNA. EF – Ts and GTP are bond exchange of GTP for bound GDP. eEF2 mediates
required for the regeneration of EF – Tu – 2GDP formation GTP driven translocation similar to prokaryotic
GTP complex. D. B. EF – G.
Ÿ First peptide linkage is now established Ÿ As eukaryotic ribosome do not have E site,
between –COOH group of amino acids at uncharged tRNAs are expelled directly from the
P site and –NH2 group of amino acid at A P site.
Free E E Ÿ The elongated peptide chain or polypeptide
site catalysed by the ezyme peptidyl
tRNA lies in the groove of the larger subunit of
transferase.
Ÿ This produces a dipeptidyl – tRNA in the A P A P A ribosome.
site and now uncharged tRNA f M et
remains bound to the P site. With the help
GDP 4
of EF – G (translocase) dipeptidyl - tRNA
C. Termination
moves from A site to P site. The ribosome GTP
moves one codon toward the 3’ end of Ÿ Termination in eukaryotes is similar to that in
mRNA (called translocation). Free tRNA prokaryotes.
slips to E site and from there to outside in Ÿ In eukaryotes, a single factor eRF1 recognises
E all three termination codons and with the
the cytoplasm.
Ÿ New codon exposed at A site attract new help of eRF3, ribosomal subunits are released.
aminoacyl tRNA complex and thus P A Ÿ eRF3 prevents the reassociation of ribosomal
peptide chain elongates. subunits in the absence of an initiation complex.

Free
4 Free tRNA polypeptide 50S
Termination Release
Ÿ Termination occurs when a non sense or stop codon (UAA, UAG, UGA) reaches A site. factor
Ÿ Stop codons are recognised by 2 release factors RF1 and RF2. A third factor RF3
mediates interaction between RF1 or RF2 with the ribosome. 5’
Ÿ RF1 is specific to UAG and UAA. 3’ 3’ mRNA
Ÿ RF2 is specific to UAA and UGA. 3’
Ÿ RFs hydrolyse the terminal peptidyl-tRNA bond, release polypeptide and last tRNA 5’ 5’
Release
from the P site and dissociates two subunits of ribosomes to start new cycle of factor
Stop codon
translation. (UAG, UAA or UGA) 30S
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