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LABORATORY MANUAL
BIOLOGY
2024-2025
 INDEX
SL.NO TITLE
MAJOR EXPERIMENT
1. ISOLATION OF DNA FROM PLANT MATERIAL
SLIDE PREPARATION
2. POLLEN GRAIN GERMINATION
3. STUDY OF MITOSIS IN ONION ROOT TIP
MINOR EXPERIMENTS
4. STUDY OF PLANT POPULATION DENSITY BY QUADRAT METHOD
5. STUDY OF PLANT POPULATION FREQUENCY BY QUADRAT
METHOD
SPOTTERS
6.
STUDY OF ADAPTATIONS OF FLOWERS FOR POLLINATION
IA. FLOWERS ADAPTED TO POLLINATION BY WIND.

.B. FLOWERS ADAPTED TO POLLINATION BY BIRDS

BIGNONIA.
I.C.FLOWERS ADAPTED TO POLLINATION BY INSECT
7. TO STUDY POLLEN GERMINATION ON STIGMA THROUGH
PERMANENT SLIDE
8. T.S. OF MAMMALIAN TESTIS (TO STUDY THE STAGES OF
SPERMATOGENESIS)
T.S. OF MAMMALIAN OVARY (TO STUDY THE STAGES OF
OOGENESIS)
9.
V.T.S. OF BLASTULA ( BLASTOCYST) THROUGH PERMANENT SLIDE.
10. MEIOSIS IN ONION BUD CELL THROUGH PERMANENT SLIDE
11. MENDELIAN INHERITANCE USING SEEDS OF DIFFERENT
COLOUR/SIZES OF ANY PLANT
12. PEDIGREE ANALYSIS FOR COLOUR BLINDNESS
13. CONROLLED POLLINATION-EMASCULATION, TAGGING
AND BAGGING
14.
COMMON DISEASE CAUSING ORGANISMS THROUGH
PERMANENT SLIDES
A.ASCARIS (ROUND WORM)
B. ENTAMOEBA HISTOLYTICA
C. PLASMODIUM.
15. SYMBIOTIC ASSOCIATION IN ROOT NODULES OF LEGUMINOUS
PLANT,CUSCUTA ON HOST AND LICHENS
A.RHIZOBIUM IN ROOT NODULES OF LEGUMINOUS PLANT
B.CUSCATA ON HOST
C.LICHENS
16. STUDY OF HOMOLOGY AND ANALOGY WITH CHARTS OF ANIMALS
AND PLANTS.
HOMOLOGY/HOMOLOGOUS ORGANS
ANALOGY/ ANALOGOUS ORGANS
MAJOR EXPERIMENT
 Experiment no.1

Date:

ISOLATION OF DNA FROM PLANT MATERIAL

Aim:

To isolate DNA from a plant material such as garden peas, papaya, banana etc.

Materials Required:

Plant material mortar and pestle, beakers, l iq u id det er g e nt 10ml, so d iu m c hlo r id e 3g,

distilled water 90ml, c h i l le d et ha no l, bo i l i ng t e st t u be , 250 ml beaker, glass rod.

Procedure:

1. Dissolve salt in 90ml water and add soap solution and mixed gently.
2. Mash the plant material with mortar and pestle.
3. Add the pulp in beaker with salty soap solution.
4. Filtered the mixture into second beaker.
5. Pour chilled ethanol to one side of the test tube having the mixture.
6. Leave the test tube undisturbed for few minutes.

Fig:DNA that separates out can be removed by spooling

Observation:

Nuclei acids precipitate into upper layer (ethanol). It appeared as collection of fine threads inthe

suspension.

Precaution:

1. Avoid formation of foam on the mixture which will contaminate the filtrate.
2. Ethanol is highly inflammable , handle it very carefully.
SLIDE PREPARATIONS
Experiment no.2
Date:

STUDY OF POLLEN GERMINATION

Aim:

To study pollen germination by preparing a temporary mount.

Materials required:
Fresh mature flower like Vinca, China Rose or datura, Glass slide ,Glass rod , Sucrose, Potassium nitrate,
Magnesium sulphate Boric acid , Compound microscope ,Cover slip ,Beaker ,Distilled water ,Dropper and
slides (cavity block slide), Cover slips, microscope and pollen grains.

Procedure:

1. Prepare the medium for pollen germination by dissolving 10 gms sucrose, 20 mg potassium nitrate, 30
gm magnesium sulphate and 10 gm boric acid in 100 ml of distilled water.
2. Using a glass rod, stir the solution to mix it well.
3. Using a dropper, take some medium and put two drops of it on a clean glass slide.
4. Now, take a fresh mature flower and dust a few pollen grains from its stamen on to the drop on the slide.
5. After few minutes, place the glass slide on the stage of the compound microscope.
6. Observe the slide carefully under a microscope at regular intervals.

Observation:

In nutrition medium, pollen grains germinated. The tube cell enlarged and came out of the pollen

grain through one of the germ pores to form a pollen tube. The generative nucleus passed into it. It soon

divided into two male gametes.

 Fig: Germination of Pollen Grain

Precaution taken:

1. Collect pollen grain from a fresh flower.

2. collect Pollen from a matured flower.

3. Use only clean slide.

4. The slide should have enough fresh Nutrient medium.

Experiment no.3
Date:

STUDY OF MITOSIS IN ONION ROOT TIP

Aim:

To observe different stages of Mitosis from the temporary mount of onion root tip.
Requirements:

Onion bulbs, conical flask/glass bottles, Petri dishes, scissors, forceps, needles, acetocarmine,
distilled water, spirit lamp, microscope, slides, cover slips, blotting paper etc.

Procedure:

1. Take a medium sized bulb of onion and trim off the old roots from its base by means of a

sharp blade.

2. Place the onion on a conical flask/glass bottle full of water, with its base touching the water.

Keep the set up for a week to grow the roots.

3. Remove 2 or 3 root tips and hydrolyze them in 1 N hydrochloric acid for 15 minutes.

4. Remove the root tips and wash them thoroughly in water.

5. Place the root tips in acetocarmine solut ion placed in watch glass and gently warm it over the

flame.

6. Take one root tip and place in on a slide and place a cover slip on the root.

7. Gently squash the root by tapping the cover slip with the blunt end of a pencil or needle until

the cells separate and spread out into a very thin layer.

8. Observe under a low power of the microscope to locate the dividing cells. Examine the different

stages of mitosis under the high power of the microscope

Observations:

Under low power of the microscope, rectangular cells with pink nucleus are seen scattered. Under

high power of the microscope following stages may be seen.

1. Prophase

i. Chromatin material shortens and condenses into thread like structures called chromosomes

ii. Each chromosome consists of two chromatids, jointed at a point called centromere

iii. Nuclear membrane and nucleolus start disintegration and disappear at the end of prophase

2. Metaphase

i. A bipolar spindle develops in the cell. Chromosomes become thick and two chromatids of

each chromosome become clear

ii. Chromosomes become arranged at the equator of the spindle

iii. Each chromosome gets attached to the spindle fibers at its centromere.

3. Anaphase

i. The two sister chromatids of each chromosome separate from the centromere and move

towards the opposite poles.

4. Telophase

i. The spindle disappears and the daughter chromosomes uncoil to form chromatin fibers at

the two poles

ii. Nuclear membrane and nucleolus reappear and two daughter nuclei appear at opposite

poles.

iii. Cytokinesis occurs by cell plate formation between the two daughter nuclei.

Precautions:

1. The base of the onion bulb should be in contact of water while growing the roots

2. Excess HCl should be removed otherwise acetocarmine will not stain the

chromosomes.

3. The slide should be warmed gently much above the flame of the spirit lamp.
Fig: Various stages of mitosis in onion root tip cells.
MINOR EXPERIMENTS
Experiment no.4
Date:

STUDY OF PLANT POPULATION DENSITY BY QUADRAT METHOD

Aim:

To study population density of plants by quadrat method

Requirements:

Field, meter scale, string or wire, nails, paper, observation note etc

Method:

1. Select a field to study the population density of the plants

2. 1 meter x 1 meter area is measured with the help of meter scale in the field to make a
quadrat.
3. Four nails are fixed at the corners of the quadrat and tied a string to it. Make four such
quadrats.
4. To make the counting easy, the quadrates are divided further to make smaller squares.
5. Select four species and label them as species-A, species –b, species-C and species D.
6. Count all the four species separately and recorded their total count.
7. Repeat the same experiment for the other four quadrates also.
8. Record the data in the observation table. And calculated the density using the formula.
 Observations:

Name of Number of plants per Total number Total number Popula

theplant quadrant area of individuals ofquadrants tion
species I II III IV in all four density
quadrants D=
S/Q

Species A 30 28 32 31 121 4 30.24

Species B 42 45 38 40 165 4 41.25

Species C 15 12 17 15 59 4 14.75

Species D 6 10 7 8 31 4 7.75

Result:
The number of individuals of a species presents per unit area or quadrant of a given time is
calledpopulation Density

Precautions:
1. Measure the quadrant accurately
2. Mark the quadrants close to each other from one field only
Experiment no.5
Date:

STUDY OF PLANT POPULATION FREQUENCY BY QUADRAT METHOD

Aim:

To study plant population frequency by quadrat method

Requirements:

Field, meter scale, string or wire, nails, paper, etc

Method:

1. Select a field to study the population frequency of the plants

2. Measure 1mx1m area with the help of the meter scale in the field to make a quadrat.

3. Fix four nails at the corners of the quadrat and tie a string to it

4. Record the particular species of plant present in each quadrates.

5. Repeat the same experiment for the other species also.

6. Record the data in the observation table and calculate the frequency using the

formula.

𝐓𝐨𝐭𝐚𝐥 𝐧𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐪𝐮𝐚𝐝𝐫𝐚𝐧𝐭𝐞𝐝 𝐢𝐧 𝐰𝐡𝐢𝐜𝐡 𝐭𝐡𝐞 𝐬𝐩𝐞𝐜𝐢𝐞𝐬 𝐨𝐜𝐜𝐮𝐫 ×𝟏𝟎𝟎

Population frequency=
Total number of quadrats studied

Observations:

Name of the Total number of quadrants in which present Total Population

plant species Quadrant Quadrant Quadrant Quadrant number of frequency
1 2 3 4 quadrants
studied
Species A X √ √ √ 4 3/4X100=75%
Species B √ √ √ √ 4 4/4X100=100%
Species C √ √ X √ 4 3/4X100=75%
Species D X √ √ X 4 2/4X100=50%
Result:

Species ‘B’ is present more percentage whereas species (D present in least

percentage.

Precautions:
1. Measure the quadrat accurately

2. Mark the quadrates close to each other from one field only.
SPOTTERS
Experiment no.6
Date:

STUDY OF ADAPTATIONS OF FLOWERS FOR POLLINATION

IA. Flowers adapted to pollination by wind

1. Stigma is large, branched and feathery.

2. Pollen grains are produced in large amounts.

3. They are often smooth and light.

4. They can be carried away by the wind currents.

5. Wind pollination is seen in grasses,

 I.B. Flowers adapted to pollination by Birds
Bignonia

1. Flowers are brightly coloured.

2. Floral parts are leathery.
3. Flowers secrete abundant watery nectar.
4. The nectar is so abundant that drops can be brought down by shaking the branches.

5. Flowers are generally odorless / without fragrance.

 I.C.Flowers adapted to pollination by insect

1. Flowers are large and brightly coloured to attract insects. In Tecomaflowers are yellow
coloured.

2. Mostly bees, wasps, Moths are attracted.

3. Flowers are gamopetalous and have tube like corollas.

4. Nectar glands are situated at the base of the pistil.

5. Pollen grains are rough and sticky so that they can easily get stuck up tothe body of the insects.

6. Stigma is rough and sticky so that they can easily catch the pollen.

7. Flowers emit characteristics smell to attract particular insects.

Fig: Insect pollinated flower

Experiment no.7
Date:

TO STUDY POLLEN GERMINATION ON STIGMA THROUGH PERMANENT

SLIDE

1. Many pollen grains are observed germinating over stigma. The sugary substance secreted by stigma
stimulates the growth of the pollen tube
2. Pollen tube penetrates deep into the stigma pushing its way through the style and the ovary.
3. Pollen tube carries tube nucleus and generative nucleus. Two male gametes are formed by the division of
generative nucleus.

Pollen grains germinating on stigma

Experiment no.8
Date:

T.S. of Mammalian Testis (To study the stages of spermatogenesis)

Identifying features:

1. A testis contains a large number of seminiferous tubules.

2. Leydig cells are present in between seminiferous tubules. They secrete themale sex hormone
testosterone.

3. Each tubule is lined by a single layer of germinal epithelium with

Spermatogonia and Sertoli cells.

4. Each spermatogonium grows into a primary spermatocyte which undergoes

meiosis to produce secondary spermatocytes and then spermatids.

5. Sertoli cells project into the lumen and provide nourishment to the
developing sperms.

6. Spermatids get embedded in the Sertoli cells and get transformed intosperms or spermatozoa.

Fig : T.S. Of Mammalian Testis

 T.S. of Mammalian Ovary (To study the stages of oogenesis)

Identifying features

1. A mammalian ovary is covered with germinal epithelium that gives rise tofollicular cells and ova.
2. The inner part of ovary called stroma is composed of connective tissue,blood vessels and
follicles in various stages of development.
3. Gamete mother cell start division and enter into prophase –I of meiosis andget temporarily arrested
called primary oocytes
4. Each primary oocyte gets surrounded by a layer of granulose cells and thencalled Primary follicle.
5. As primary follicle gets surrounded by more layers of granulose and newtheca called secondary
follicles.
6. Secondary follicle soon transformed into tertiary follicle with a fluid filledcavity called antrum.
7. Now the primary oocyte grows in size and completes first meiotic divisionand forms large haploid
secondary oocyte and a tiny first polar body.
8. The tertiary follicle further changes into mature follicle or graafian folliclewith large fluid-filled
(antrum) cavity.
9. Finally, the Graafian follicle ruptures to release ova from the ovary.
10. The cells of ruptured follicle from another structure called corpus
 Secondary follicle

Fig: T.S. of Mammalian Ovary

Experiment no.9
Date:

V.T.S. Of Blastula ( Blastocyst) through permanent slide.

1. Zygote after cleavage forms 2-16 cells.

2. These cells are called blastomeres.

3. The embryo with 8- 16 blastomeres is called morula.

4. The morula continues to divide and transformed into blastocyst.

5. The blastomeres in the blastocyst are arranged in to an outer layer called

trophoblast and inner group of cells attached to trophoblast called inner cell mass.

Fig: T.S. Of Blastula

Experiment no.10
Date:
MEIOSIS IN ONION BUD CELL THROUGH PERMANENT SLIDE

A. MEIOSIS- I
1. Prophase I - It is of long duartion and has five sub stages:

a) Leptotene
i) Chromatin fibres condense and form thick thread like structures called chromosomes.
ii) Nuclear envelop and nucleolus are distinct.
b) Zygotene
i) Homologous chromosomes form pairs called bivalent. This pairing is called synapsis.
ii) The individual of a pair are similar in length and in position of their centromere.
c) Pachytene
i) The two chromatids of each chromosome become visible, so that a bivalent becomes a tetrad.
d) Diplotene
i) The two chromosomes of each bivalent move away and homologous are held together at one or more
points called chiasmata.
e) Diakenesis
i) Homologous chromosomes appear thick and ring shaped.
ii) Nucleolus and nuclear envelope disappear and spindle begins to be formed.
2. Metaphase I
i) The bivalent (homologous chromosomes) arrange themselves at the equator of the spindle.
ii) The spindle get attached to the centromere of the chromosome.

3. Anaphase I
i) The two chromosomes of each bivalent move to the opposite pole.
ii) Each pole has half the number of chromosomes with two chromatids each.
4. Telophase I
i) The chromosome at each pole uncoil, and nucleolus and nuclear envelope reappear.
ii) Cytokinesis occurs to form two haploid daughter cells.
Interkinesis
A very short interphase may intervene between meiosis I and meiosis II.
 B. MEIOSIS II
It includes following four stages:
1. Prophase II
i) The chromosomes of daughter cell begin to condense and become thick.
ii) Nuclear envelope and nucleolus begin to disappear.
2. Metapahe II
i) The chromosomes are arranged on the equator of the spindle.
ii) Each chromosome is held by the spindle at the centromere to both the poles.
3. Anaphase II
i) The sister chromatids(daughter chromosomes) of each chromosome separate and migrate towards the
opposite poles.
ii) Each pole, thus receives haploid number of chromosomes.
4. Telophase II
i) The chromosomes begin to uncoil and become thin.
ii) The nuclear envelope and nucleolus are reconstituted.
Cytokinesis occurs and four daughter cells are formed, each with haploid number of chromosomes.
Experiment no.11
Date:

MENDELIAN INHERITANCE USING SEEDS OF DIFFERENT COLOUR/SIZES OF

ANY PLANT

Aim: Mendelian inheritance using seeds of different colour/sizes of any plant

Material/Apparatus Required:
Peas seeds samples, Petri dish , Notebook , Pencil/ pen
Procedure:
1. Take about 100 pea seeds in a tray.
2. Separate out round and wrinkled and put in separate Petri dish.
3. Note down the number of round and wrinkled seed and calculate their appropriate ratio.
4. Repeat the process for the other contrasting traits of the seed i.e., yellow and green colour.

Observations:
Out of 100 pea seeds observed for monohybrid inheritance or round dominant and wrinkled recessive seed,
the following observations were made.

Sr. Character / Total no. of No. of seed Appropriate

no. traits of the seed seed observed showing ratio
contrasting form
of the trait

1. Seed 106 80 (Round): 26 3:07:1

colour(yellow/ (wrinkled)
Wrinkeld)

Conclusion:
The contrasting forms in both the traits of pea seed, the ratio is exactly the same as obtained by
Mendel for monohybrid crosses i.e. 3:1.
Experiment no.12
Date:

PEDIGREE ANALYSIS FOR COLOUR BLINDNESS

AIM:

To analyses the gives pedigree chart for colour blindness

1. Trait of colour blindness is represented by shaded symbols while normal individual denoted by

open symbols

2. The pedigree chart represents phenotypically normal parents producing three daughters and one

son, who is colour blind

3. phenotypically normal female with normal male have two daughters and two sons with one son

colour blind. It gives the following result:

a) Colour blindness is sex linked disease related with ‘X’ chromosome.

b) X chromosomes in females with homozygous condition produce colour blind and

heterozygous condition carrier offspring.

c) Male is a sufferer or normal but never a carrier, since Y chromosome is not having gene

for this trait. Female parent is a carrier for colour blindness in the given chart.
 XA Y XA Xa

Xa Y XA Xa Xa Y XA XA XAXa

XAY XAXa XaXa XaY

Fig: Colour blindness

Experiment no.13
Date:

CONROLLED POLLINATION-EMASCULATION, TAGGING AND

BAGGING

1. Emasculation
Comment

1. This method is employed in the crops having flowers of sufficiently largesize flowers.

2. The instrument used in this method includes pocket lens, forceps, needle,scissors, scalpel, camel
hair brush etc.

3. In this process anthers are removed from the flowers before their maturation

2. Identification. Bagging, tagging and labeling

Comment

1. After emasculation, the flowers are covered with small bags to preventpollination with
undesired pollen grains

2. These bags are made up of polythene or paper.

3. After dusting of the desired pollen grains on the emasculated flowers, thebags are rebagged

4. A tag on the plant which displays the date of emasculation, crossing andbrief account of the
parent.
Plant Name: Clitoria ternatea

Date of Hybridization:

Variety: Blue & White

Fig: Clitoria ternatea.

Experiment no.14
Date:
COMMON DISEASE CAUSING ORGANISMS THROUGH
PERMANENT SLIDES
A.Ascaris (round worm)
Comments:

1. Roundworm or Ascaris causes the diseases called Ascariasis.

Fig: Ascaris

2. It is unisexual. Male worm has curved tail end whereas female is straight Male is smaller than female.

Genital aperture in female is in mid-ventral side. It is an endoparasite found in the intestine of man.

3. Symptoms includes impaired digestion, diarrohoea and vomiting.

4.Generally a large number of adult ascaris worm infest a single host, and obstruct the intestinal passage and
thereby cause abdominal discomforts like colic pains.
 B. Entamoeba Histolytica
Identification: Entamoeba histolytica.

Disease caused: Amoebiasis or amoebic dysentery.

Comments:
1. It is an endoparasite living in the large intestine.

2. It causes diseases called amoebic dysentery.

3. The symptoms include abdominal pain, repeated motion with blood and mucus.

4. It is unicellular.

5. There is a single nucleus and many food vacuoles.

6. It feeds on Red blood corpuscles by damaging walls of large intestine.

Fig: Entamoeba histolytica.

 C. Plasmodium.
Identification: Plasmodium vivax.

Disease: Malaria.

Comments:
1. Plasmodium enters into human body in sporozoite stage by bites of female Anopheles
mosquito.

2. The parasite is spindle shaped and uninucleate.

3. The sporozoites enter into RBC after infecting liver cells.

4. In RBC it becomes merozoites and produce haemozoin, after rupture of RBC, haemozoin is
released in blood which is responsible for chill and high fever.

5. Gametocyte (sexual stage) develops in RBC.

6. Gametocytes reach mosquito stomach and produce male and female gametes.

7. Male and female gametes fuse to form zygote which form oocytes.

8. Oocytes produce spermatozoites which reach salivary gland of mosquito and make the
mosquito infective

Fig: Plasmodium vivax

Experiment no.15
Date:

SYMBIOTIC ASSOCIATION IN ROOT NODULES OF LEGUMINOUS

PLANT,CUSCUTA ON HOST AND LICHENS

A.RHIZOBIUM IN ROOT NODULES OF LEGUMINOUS PLANT

1. Rhizobium bacteria are present in root nodules of leguminous plant and form a symbiotic
relationship,mutualism, where both are benefited from each other.
2. Nitrogen fixing bacteria like Rhizobium fixes atmospheric nitrogen into nitrogenous
compounds.
3. Rhizobium can convert atmospheric nitrogen to ammonia that can be used by pea plant for
growth and development.
4. Bacteria receive nutrients and suitable place to grow from plant.
 B.CUSCATA ON HOST

1. Cuscuta commonly called dodder or amerbel and live as stem ectoparasite on

other plants.

2. Cuscuta has no fully expanded form of leaves (scale like leaves are present) and
has no chlorophyll.

3. Stem of cuscuta is thin and slender shaped and tt winds around the stem of host
plant. Stem of cuscuta fixes itself to the stem of host plant with special structures
called haustoria.

4. Haustoria forms direct connection to the vascular bundles of the host and
withdraw water,carbohydrates and other solutes.

5. Roots of cuscuta are temporary and die as soon as it makes connection with host
plant.

6. Cuscuta can weaken or kill plant and reduce crop yield.

 C. LICHENS

1. Lichens are composite organisms representing a symbiotic association (mutualism)

between fungus and algae.
2. The algal component is known as phycobiont and fungal component is known as
mycobiont.
3. Algae prepare food for fungi and fungi provide shelter and absorb mineral,nutrients and
water for its partner.
4. They grow on lands,rocks,tree trunks and walls of houses,like dry vegetation.
 Experiment no.16
Date:

STUDY OF HOMOLOGY AND ANALOGY WITH CHARTS OF ANIMALS

AND PLANTS.
HOMOLOGY/HOMOLOGOUS ORGANS

The structures depict the forelimbs of man, cheetah, whale and bat in the case of
animals.
1. The hand of man, limb of cheetah, flipper of a whale and the wings of a bat have
common set of bones but all of these structures though appears similar but are involved in
different functions grasping, running, swimmimg and flying respectively.

2. The structures depict Bougainvillea(thorn) and Curcurbita tendrils in case of plants.

 The leaves of the plant Bougainvillea have been modified into thorns for protection
while leave sof cucurbita are made into tendrils for providing support to the climbers.
3. These structure of animals and plants under study show homology,i.e.similarity in the
fundamental basic structures due to shared or common embryonic origin but all of these
organs/ features performs different functions.

ANALOGY/ ANALOGOUS ORGANS

1.The forelimbs of bats, birds and wings of insects are used for flying by these animals
however, they are structurally very different from each other.

a- Modified underground stems (Carrot) b) Modified roots- Rhizome of ginger

2. Modified stems (rhizome, corm, tuber) are analogous to modified roots (carrot,
radish) as they perform similar function of storage of food but their origin is different.
Rhizome of ginger, potato tuber, Colocasia are stems and beetroot, radish etc. are roots.