Biology-practical Class 12

Std. XII Science: Biology Practical Handbook

Std. XII Sci.

Biology Practical Handbook

Prof. Mamta R. Solanki M.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]

Biology Practical Handbook (New Syll abus)

Target Publications Pvt Ltd.

Second Edition: July 2012

Price:

45/-

Printed at:

Gogri Offset Prin ters 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 6551 email: [email protected]

PREFACE Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution and taxonomy. It provides detailed information about the zoological as well as botanical aspects of life with intensive study of different species of plants and animals, internal structure of human body, physical and 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, cardiology, zoology, pisciculture, epiculture, sericulture etc. Therefore it is necessary to have a firm grip over such an extensive subject and its practical application. Hence we bring to you

“Std. XII Sci. : BIOLOGY PRACTICAL HANDBOOK”

a handbook

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. It covers the entire syllabus with different sets of practical written in a systematic and comprehensive manner. The diagrams included are neat, labeled and well drawn to provide an imagination of what they look like in real. The handbook also 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 for improvement and hence we welcome all suggestions and regret any errors that may have occurred in the making of this book. A book affects eternity; one can never tell where its influence stops.

Best of luck to all the aspirants! Yours faithfully

Publisher

TARGET Public ations

Biol ogy Practical Handb ook

A-01 To dissect the given flowers and display different whorls 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.

Stigma n e m a t S

Anther Style

Filament

l i t s i P

Ovary Petal

Ovule Placenta

Sepal Thalamus Pedicle Parts of a typical flower

Anther Anther Style Ovary Sepals

Petals

Stamens

Carpel

Dissected parts of a flower 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

Std. XII Sci.: Biol ogy

1

TARGET Public ations vii. viii. ix. x. xi.


Pedicellate: flower with stalk Incomplete: does not have all the four whorls Trimerous: floral leaves of each whorls are three on in multiple of three Tetramerous: floral leaves of each whorls are four or in multiple of four 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.

Stamen

Stamen Petal

Petal Carpel

Stigma

Sepal

Thalamus

Thalamus

Hypogynous flower

Perigynous flower

Thalamus Epigynous flower

Hypogynous, perigynous and epigynous flowers


2

TARGET Public ations E.

F.

G.

H.


Cohesion of sepals i.

Polysepalous: Sepals are free from each other

ii.

Gamosepalous: Sepals are fused with each other

Cohesion of corolla i.

Polypetalous: Petals are free from each other

ii.

Gamopetalous: Petals are united with each other

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

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

Monoadelphous

Diadelphous

Polyadelphous

Syngenesious

Synandrous

Different types of cohesion of anthers 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


3

TARGET Public ations iii. J.


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

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.

Anther Connective Filament Adnate

Basifixed

Dorsifixed

Versatile

Attachment of anthers to the filament 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


4

TARGET Public ations v. iv.


Pentalocular: with five locules Multilocular: with many locules

Ovary wall

Ovules Locules Placenta

Locules Unilocular

Locules Bilocular

Trilocular

Tetralocular

Pentalocular

Types of ovaries based on the number of 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. Hibiscus

iii.

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.

Placenta Locules

Ovary wall Free central

Axile

Loculus Anther

Ovule

Parietal

Ovule

Ovule

Placenta Various types of placentation


Basal

Superficial 5



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

Valvate

Twisted

Imbricate

Quincuncial

Vexillary

Different types of aestivation in floral members 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


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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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Stigma Style

Ovary

Complete flower

Stamens

Carpel

Placenta Locule ovule

Ovary wall

Sepals


Petals

T.S. ovary

8

TARGET Public ations 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,

vi.

a.

large upper posterior petal – standard or vexillum

b.

two lateral petals-wings or alae

c.

two anterior or innermost petal – keel or carina

Androecium: Stamens 10, diadelphous

a. vii.

Anther–bithecous

Gynoecium: Monocarpellary

a.

ovary – superior, unilocular with marginal placentation

b.

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

Standard Standard (Vexillum) Alae (Wing) Keel (Carina) Stamen

Wing Keel

Sepal Pistil

Opened Corolla

V.S. of flower

Stigma

Style Ovary Pistil Stamens (9)+1(Diadelphous)


Gynoecium

9



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.

Petal Stigma

Stamen Style

Sepals

Sepal Ovary

Pedicel

Thalamus L.S. of flower

Stigma Anther lobe Style Connectives

Ovary wall Ovule Placenta

Filament

Stamen

Ovary T.S. of ovary A Pistil


10



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 to fusion with staminal tube, twisted aestivation. vi. Androecium: Stamens indefinite, monoadelphous, anther – monothecous, reniform. vii. Gynoecium: Pentacarpellary, syncarpous, ovary pentalocular with axile placentation. Stigma Stamens Style

Sepal Epicalyx

Petal Staminal tube

Sepals Petals

Ovary Epicalyx

Thalamus L.S. of flower

Stigmas Ovary wall Ovules Placenta Locule

Stamens Style

A Stamen

Ovary wall T.S. of ovary

Ovary Gynoecium


11



Onion (Allium cepa) i.

Family: Liliaceae

ii.

Flowers: Bracteate, bisexual, 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.

pedicellate,

complete,

trimerous,

actinomorphic,

Anther Stigma

Filament

Style Ovary

Inflorescence

Ovule Thalamus A Stamen

L.S. Flower

Stamens

Locule Ovule

Ovary

Ovary wall

Stigma Style Trilobed Ovary

Placenta

Tepals

Septum A Flower

T.S. Ovary

A Gynoecium

Precaution

1.

Take fresh flower to dissect out the floral parts

2.

Take thin and uniform section of the ovary.


12



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


13



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.


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Biology-practical Class 12

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