Biology-practical Class 12

8/17/2019 Biology-practical Class 12

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Std. XII Science: Biology Practical Handbook


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Std. XII Sci.

Biology Practical Handbook

Prof. Mamta R. SolankiM.Sc., B.Ed., Nagpur

R. Jhunjhunwala College, Ghatkopar

Salient Features:

Written as per the needs and requirements of the Board Exam.

Neat and labeled diagrams.

Question and Answers for quick revision of oral exam.

Self evaluative in nature.

Target PUBLICATIONS PVT. LTD. Mumbai, Maharashtra

Tel: 022 – 6551 6551

Website: www.targetpublications.in

www.targetpublications.org

email : [email protected]


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Std XII Sci

Biology Practical Handbook(New Syllabus)

Target Publications Pvt Ltd.

Second Edition: July 2012

Price: 45/-

Printed at:

Gogri Offset Printers Andheri (E)Mumbai – 400 069

Published by

Target PUBLICATIONS PVT. LTD.Shiv Mandir Sabhagriha,Mhatre Nagar, Near LIC Colony,Mithagar Road,Mulund (E),Mumbai - 400 081

Off.Tel: 022 – 6551 6551email: [email protected]


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PREFACE

Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growt

origin, evolution, distribution and taxonomy. It provides detailed information about the zoological as well as botanic

aspects of life with intensive study of different species of plants and animals, internal structure of human body, physical an

chemical functions of tissues, organs and organ systems, and many other aspects.

Practical application of biology is of utmost importance in the field of physiology, neurology, biochemistry, cardiolog

zoology, pisciculture, epiculture, sericulture etc. Therefore it is necessary to have a firm grip over such an extensive subje

and its practical application. Hence we bring to you “Std. XII Sci. : BIOLOGY PRACTICAL HANDBOOK” a handboo

which is a complete and thorough guide for the effective preparation.

This handbook is written according to the needs and requirement of the board exam and helps the student to score high.

covers the entire syllabus with different sets of practical written in a systematic and comprehensive manner. The diagram

included are neat, labeled and well drawn to provide an imagination of what they look like in real. The handbook al

includes all the necessary information regarding the practical.

And lastly, we would like to thank all those who have helped us in preparing this book. There is always room fo

improvement and hence we welcome all suggestions and regret any errors that may have occurred in the making of this boo

A book affects eternity; one can never tell where its influence stops.

Best of luck to all the aspirants!

Yours faithfully

Publisher


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TARGET Publications Biology Practical Handbook

Std. XII Sci.: Biology 1

To dissect the given flowers and display different whorlsA-01

Introduction

A modified shoot meant for reproduction is called flower. A flower consists of receptacle on which

its four whorls are born. These are calyx, corolla, androecium and gynoecium.

A. Study the following terminology.

i. Bracteolate: flower with bracteoles

ii. Bracteoles: leaf like appendage in the axil of a flower

iii. Bract: leaf like appendage at the base of the flower

iv. Ebracteate: flower without bract

v. Bracteate:flower bearing bract.

vi. Sessile flower: flower without stalk

Stigma

Style

Ovary

Petal

Sepal

Thalamus

Pedicle

Anther

Filament

Ovule

Placenta

S t a m e n

P i s t i l

Parts of a typical flower

Dissected parts of a flower

Petals

Anther

Stamens

Anther

Style

Ovary

CarpelSepals


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vii. Pedicellate: flower with stalk

viii. Incomplete: does not have all the four whorls

ix. Trimerous: floral leaves of each whorls are three on in multiple of three

x. Tetramerous: floral leaves of each whorls are four or in multiple of four

xi. Pentamerous: floral leaves of each whorls are five or in multiple of five

B. Symmetry of flower

i. Actinomorphic: A flower can be divided into two equal halves when cut through any

radial plane passing through the centre of the flower.

ii. Zygomorphic: A flower can be divided into two equal halves by only one plane which

passes radially through the centre.

iii. Asymmetrical: A flower which cannot be divided into two equal halves by any plane.

C. Bisexual and Asexual

i. Bisexual: flower with both male and female sex organs

ii. Unisexual: flower with either male or female flowers.

iii. Staminate: flower with only male sex organ.

iv. Pistillate: flower with only female sex organ.

D. Insertion of floral leaves of thalamus

i. Hypogynous: When the ovary positioned above receptacle of a flower, it is called

superior ovary.

Having the floral part such as sepal, petals and stamen born on the receptacle beneath the

ovary.

ii. Perigynous flower: Flower having sepals, petals and stamens around the edge of a

cuplike receptacles. Ovary is semi inferior.e.g. rose and cherry.

iii. Epigynous flower: Flower having sepals, petals and stamens above the ovary. Ovary is

superior ovary.

Carpel

Stamen

Petal

SepalThalamus

Hypogynous flower Perigynous flower

Thalamus Thalamus

Epigynous flower

Hypogynous, perigynous and epigynous flowers

Petal

Stamen

Stigma


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Monoadelphous Diadelphous Polyadelphous Syngenesious Synandrous

Different types of cohesion of anthers

E. Cohesion of sepals

i. Polysepalous: Sepals are free from each other

ii. Gamosepalous: Sepals are fused with each other

F. Cohesion of corolla

i. Polypetalous: Petals are free from each other

ii. Gamopetalous: Petals are united with each other

G. Perianth: Calyx and corolla are not differentiated and called as perianth. Individual members

of perianth is called tepal.

i. Gamophyllous: Tepals are fused

ii. Polyphyllous: Tepals are free

H. Cohesion of stamens

i. Monoadelphous: When filaments are fused together and form a tube like structure

e.g. Hibiscus

ii. Diadelphous: When filaments of all the stamens are fused in two groups. e.g. Pea.

iii. Polyadelphous: When filaments are united in many groups.e.g. Lemon

iv. Syngenesious: When anthers of all the stamens are fused and filaments are free.

e.g. Sunflower

v. Synandrous: When all the stamens as well as filaments are united to form a compound

structure. e.g. Cucurbita

I. Adhesion of stamen

i. Epipetalous: When the stamens are fused with the petals e.g. Petunia

ii. Epiphyllous: When the stamens are fused with perianth e.g. Asphodelus


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iii. Gynandrous: When the stamens are fused with gynoecium e.g. Calotropis

J. Attachment of anther to the filament

i. Basifixed: Filaments attached to the base of anther lobes.

ii. Dorsifixed: Filaments attached to the dorsal side of anther

iii. Adnate: Filaments runs up from base to the apex i.e throughout the length of anther.

iv. Versatile: Filament is attached to the back of anther at a single point only so that it can

swing freely in the air as in many grasses.

K. Number of anther lobe

i. Monothecous: When there is only one anther lobe.

ii. Dithecous: When there are two anther lobes.

L. Gynoecium

Number of carpels

i. Monocarpellary: flower with one carpel

ii. Bicarpellary: flower with two carpels

iii. Tricarpellary: flower with three carpels

iv. Tetracarpellary: flower with four carpels

v. Pentacarpellary: flower with five carpels

vi. Multicarpellary: flower with numerous carpels

M. Position of carpels

i. Superior: When ovary is born below the other floral whorls

ii. Inferior: When ovary is born above the other floral whorls

N. Locules in the ovary

i. Unilocular: with one locule

ii. bilocular: with two locules

iii. Trilocular: with three locules

iv. Tetralocular: with four locules

Anther

Connective

Adnate Basifixed Dorsifixed Versatile

Attachment of anthers to the filament

Filament


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v. Pentalocular: with five locules

iv. Multilocular: with many locules

Placentation:

The arrangement of ovules in the chamber of the ovary is called placentation.

i. Marginal: Ovary unilocular and placenta develops along the ventral suture e.g. Pea.

ii. Axile: Ovary many chambered, syncarpous and placenta develop from the central axis

e.g. Hibiscusiii. Central: Ovary multi carpellary, syncarpous but one chambered and placenta develop

from the central axis e.g. Dianthus

iv. Parietal: Ovary multi carpellary, syncarpous but one chambered and the placenta arises

from the inner wall of the ovary e.g. Poppy

v. Basal: Ovary monocarpellary, with one locule and the placenta develops at the base of

the ovary e.g. Sunflower

vi. Superficial: Ovary polycarpellary, syncarpous and with many locules and the placenta

develop all around the inner surface of the partition wall e.g. Water lily.

Unilocular Bilocular Trilocular Tetralocular Pentalocular

Ovary wall

Locules

Ovules

Locules

Locules

Placenta

Types of ovaries based on the number of locules

Various types of placentation

Axile Free central

AntherOvule

Placenta

LoculesOvary wall

ParietalOvule

Placenta

SuperficialBasal

Loculus

Ovule


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Aestivation:

Arrangement of accessory whorls in relation to one another in the floral bud.

Valvate: Petals just meet each other at their edges but do not overlap e.g. Anona

Twisted: Margins of petals overlap each other e.g. Hibiscus.

Imbricate: Margins of petal overlap each other in such a way that one petal is completely

external,one petal is completely internal e.g. Cassia, Bauhinia.

Quincuncial: Margins of petal overlap each other in such a way that two petals are completely

external, two petals are completely internal e.g. Psidium guajava (Guava).

Vexillary:Typical aestivation of papilionaceous corolla.Posterior petal is external and largest, it

almost covers two lateral petals and lateral petals in turn overlap two smallest anterior petals e.g.

Pisum sativum

Stigma:

It is the apical end of the style

i. Plumose: when feather like

ii. Discoid: when disc shaped

iii. Bifid: when divided into two

iv. Capitate: when knob-shaped

Different types of aestivation in floral members

Valvate Twisted Imbricate Quincuncial Vexillary


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Study of different whorls of a flower and the chamber of anther and ovary

Aim:

To study/ To dissect the given flowers to display different whorls and to dissect anther and ovary to

show number of chambers.

Requirement:

Flower (such as Brassica, Lathyrus, Petunia, Hibiscus), forceps, blade, slides, two needles,coverslips, dissecting microscope,white paper.

Procedure

i. Take the given flower.

ii. Observe the presence of different whorls of floral leaves. i.e calyx, corolla, androecium and

gynoecium.

iii. Take out floral leaves of each whorl and place them whorl wise on a white paper

iv. Arrange them according to following order;

epicalyx (if present), sepals, petals, stamen and carpels.

v. Count the number of floral leaves of each whorl and observe the cohesion or adhesion.

vi. Take the section of ovary with the help of a blade.

vii. Mount the section on a slide in a drop of water.

viii. Observe the section under dissecting microscope.

ix. Count the number of chambers in ovary.

x. Draw the diagram of floral leaves of each whorl and transverse section of anther and ovary of

the given flower.

Following features can be seen in the given flower:

1. Brassica (mustard)

i. Family: Cruciferae

ii. Flower: Pedicellate, Actinomorphic, Hermaphrodite, Complete.

iii. Epicalyx: Absent

iv. Calyx: Sepals 4, polysepalous, petaloid

v. Corolla: Petals 5, polypetalous, cruciform

vi. Androecium: Stamen 6, tetradynamous, Anther bithecous

vii. Gynoecium: bicarpellary, syncarpous ovary.

viii. Ovary: Bilocular with parietal placentation.


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Complete flower Stamens Carpel

Stigma

Style

Ovary

Sepals Petals T.S. ovary

Placenta

Locule

ovule

Ovary wall


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2. Lathyrus (sweet pea)

i. Family: Leguminosae, sub family:Papillionaceae.

ii. Flower: Pedicellate, zygomorphic, hermaphrodite, complete, irregular, hypogynous and

papilionaceous, white or pink colour.

iii. Epicalyx : Absent

iv. Calyx : Sepals 5, gamosepalous

v. Corolla: Petals 5, polypetalous, papillionaceous,

a. large upper posterior petal – standard or vexillum

b. two lateral petals-wings or alae

c. two anterior or innermost petal – keel or carina

vi. Androecium: Stamens 10, diadelphous

a. Anther–bithecous

vii. Gynoecium: Monocarpellary

a. ovary – superior, unilocular with marginal placentation

b. style – long and bend at base, stigma – flattened and hairy.

Standard (Vexillum)

Alae (Wing)

Keel (Carina)

Stamen

SepalPistil

V.S. of flower

Standard

Wing

Keel

Opened Corolla

Stigma

Style

GynoeciumStamens

(9)+1(Diadelphous)

PistilOvary


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3. Petunia

i. Family: Solanaceae

ii. Flower: Bracteate, pedicellate, bisexual, hermaphrodite, actinomorphic, pentamerous,

hypogynous.

iii. Epicalyx : absent

iv. Calyx: sepals 5, gamosepalous, green in colour

v. Corolla: petals 5, gamopetalous

vi. Androecium: stamen 5, epipetalous, anther bithecous.

vii. Gynoecium: Bicarpellary, syncarpous, ovary bilocular with axile placentation.

Ovary wall

Placenta

Ovule

T.S. of ovary

Sepals

Pedicel

Stigma

Style

Ovary

A Pistil

Stigma

Petal

Stamen

Style

Sepal

Ovary

Thalamus

L.S. of flower

Anther lobe

Connectives

Filament

Stamen


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4. Hibiscus (china – rose)

i. Family: Malvaceae

ii. Flower: Pedicellate, regular, pentamerous, bisexual, hypogynous, large, ebracteate,

actinomorphic, complete.

iii. Epicalyx: 5 to 7, free, green.

iv. Calyx: Sepals 5, gamosepalous, green, valvate aestivation

v. Corolla: Petals 5, brightly coloured, polypetalous or slightly fused at the base due tofusion with staminal tube, twisted aestivation.

vi. Androecium: Stamens indefinite, monoadelphous, anther – monothecous, reniform.

vii. Gynoecium: Pentacarpellary, syncarpous, ovary pentalocular with axile placentation.

A Stamen

Petals

Sepal

Epicalyx

Sepals

Stigma

Stamens

Style

Petal

Staminal tube

Ovary

EpicalyxThalamus

L.S. of flower

Stamens

Stigmas

Style

Ovary

Gynoecium

Placenta

Ovules

Locule

Ovary wall

T.S. of ovary

Ovary wall


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5. Onion (Allium cepa)

i. Family: Liliaceae

ii. Flowers: Bracteate, bisexual, pedicellate, complete, trimerous, actinomorphic,

hermaphrodite and hypogynous

iii. Perianth: 6 tepals in two whorls of 3 each, polyphyllous, slightly fused at the base,

white, imbricate aestivation.

iv. Androecium: Stamens 6 in two whorls of 3 each, filament short, anther-dithecous

v. Gynoecium: carpels-3, syncarpous, ovary superior, trilocular, ovules 2 or more in each

locule, arranged on axile placentation.

Precaution

1. Take fresh flower to dissect out the floral parts

2. Take thin and uniform section of the ovary.

Inflorescence

Anther

Filament

A Stamen

StigmaStyle

Ovary Ovule

Thalamus

L.S. Flower

Stamens

Ovary

Tepals

A Flower

Stigma

Style

Trilobed Ovary

A Gynoecium

Ovary wall

Locule

Ovule

Placenta

Septum

T.S. Ovary


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Viva voce

Q.1. What is a flower?

Ans. A modified shoot meant for reproduction is called flower.

Q.2. Which are the essential whorls of flower?

Ans. Androecium and gynoecium are the essential whorls of a flower.

Q.3 Define polypetalous and polysepalous condition of flower?

Ans. When petals are free :Polypetalous

When sepals are free :Polysepalous.

Q.4. What is placentation?

Ans. The arrangement of ovules in the chamber of the ovary is called placentation.

Q.5. What is monothecous and Dithecous anther?

Ans. When there is only one anther lobe in anther it is called monothecous, when there are two

lobes in anther it is called dithecous.

Q.6. What are monoadelphous and diadelphous stamens?

Ans. When all the stamens are grouped in a single group it is called monoadelphous stamens.

When stamens are grouped in two groups, they are called diadelphous stamens.

Q.7. What is flower’s importance to plant?

Ans. Flower helps in reproduction thus helps in continuation of species.

Q.8. To which family sweet pea belongs?

Ans. Sub family papilionaceae.

Q.9. To which family china rose belongs?

Ans. Malvaceae

Q.10. How many stamens are found in china rose?

Ans. Infinite.

Q.11. Mention the characteristics of gynoecium in china rose.

Ans. Ovary is pentacarpellary, syncarpous and superior.

Q.12. How many stamens are found in sweet pea?

Ans. Ten stamens arranged in two groups (9) + 1.

Q.13. What is the condition of ovary in sweet pea ?

Ans. Ovary is unilocular, superior with marginal placentation


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Q.14. What is the condition of stamens in sweet pea?

Ans. Diadelphous (9) + 1

Q.15. What type of corolla is found in solanaceae?

Ans. Gamopetalous, rotate, five lobed

Q.16. What type of gynoecium is found in Petunia?

Ans. Bicarpellary, syncarpous, ovary superior, bilocular with axile placentation

Q.17. To which family onion belongs?

Ans. Family liliaceae

Q.18. How many stamens are found in liliaceae?

Ans. Six, arranged in two whorls

Q.19. What is perianth?

Ans. When there is no distinction between calyx and corolla and the two are collectively known as

perianth. Individual member of perianth is called tepal.

Q.20. Define following terms/terminology.Bracteate, Ebracteate, Sessile, Pedicellate, Incomplete, Trimerous, Tetramerous, Pentamerous,

Actinomorphic, Zygomorphic, Asymmetrical, Bisexual, Unisexual, Staminate, Pistillate,

Hypogynous, Perigynous, Epigynous.

Ans. Refer Introduction.

Biology-practical Class 12

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