Download Std. XII Science: Biology Practical for 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:
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9
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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]
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 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 Publications
Biology Practical Handbook
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.
Pistil
Stamen
Stigma
Anther
Style
Filament
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
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viii.
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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
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F.
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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
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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
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Pentalocular: with five locules
Multilocular: with many locules
Ovary wall
Ovules
Locules
Placenta
Locules
Locules
Unilocular
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
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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
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
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Lathyrus (sweet pea)
i.
ii.
iii.
iv.
v.
vi.
vii.
Family: Leguminosae, sub family:Papillionaceae.
Flower: Pedicellate, zygomorphic, hermaphrodite, complete, irregular, hypogynous and
papilionaceous, white or pink colour.
Epicalyx : Absent
Calyx : Sepals 5, gamosepalous
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
Androecium: Stamens 10, diadelphous
a.
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
Sepal
Wing
Keel
Pistil
Opened Corolla
V.S. of flower
Stigma
Style
Ovary
Pistil
Stamens
(9)+1(Diadelphous)
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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
Sepal
Ovary
Thalamus
Sepals
Pedicel
L.S. of flower
Stigma
Anther lobe
Style
Connectives
Ovary wall
Ovule
Placenta
Filament
Stamen
Ovary
T.S. of ovary
A Pistil
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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
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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.
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.
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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.
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