INVOLVEMENT LEADS TO EXCELLENCE

GRADE 12 BIOLOGY PRACTICAL MANUAL

A. List of Experiments

1. Prepare a temporary mount to observe pollen germination.

2. Study the plant population density by quadrate method.
3. Study the plant population frequency by quadrate method.
4. Prepare a temporary mount of onion root tip to study mitosis.
5. Isolate DNA from available plant material such as spinach, green pea seeds, papaya, etc.

B. Study and observe the following (Spotting):

1. Flowers adapted to pollination by different agencies (wind, insects, birds).

2. Pollen germination on stigma through a permanent slide or scanning electron micrograph.
3. Identification of stages of gamete development, i.e., T.S. of testis and T.S. of ovary through
permanent slides (from grasshopper/mice).
4. Meiosis in onion bud cell or grasshopper testis through permanent slides.
5. T.S. of blastula through permanent slides (Mammalian).
6. Mendelian inheritance using seeds of different colour/sizes of any plant.
7. Prepared pedigree charts of any one of the genetic traits such as rolling of tongue, blood groups,
ear lobes, widow's peak and colour blindness.
8. Controlled pollination - emasculation, tagging andbagging.
9. Common disease causing organisms like Ascaris, Entamoeba, Plasmodium, any fungus causing
ringworm through permanent slides, models or virtual images or specimens. Comment on symptoms
of diseases that they cause.
10. Models specimen showing symbolic association in root modules of leguminous plants, Cuscuta on
host, lichens.
11. Flash cards models showing examples of homologous and analogous organs.
EXPERIMENT 1: STUDY OF POLLEN GERMINATION
AIM: To study the pollen germination on slide
MATERIALS REQUIRED: Flowers, needles, safranin stain, glycerin, boric acid, magnesium sulphate,
potassium nitrate, sucrose, slide, beaker, cover slips, and microscope.
PROCEDURE:
➢ Prepare a nutrient solution by dissolving 10 gram sucrose, 10 gram boric acid, 30mg
magnesium sulphate and 20 mg potassium nitrate in 100ml of water.
➢ Take a few drops of this solution on a clean slide and dust a few pollen grains from the stamen
of a mature flower on it.
➢ Observe the slide in the microscope after 5 minutes and then observe it regularly for about
half an hour.
OBSERVATION:
➢ In nutrient medium, the pollen grain germinates.
➢ The tube cell enlarges and comes out of the pollen grain through one of the germ pore to
form a pollen tube.
➢ The tube nucleus descends to the tip of the pollen tube.
➢ The generative cell also passes into it. It soon divides into two male gametes.
➢ Each male gamete is lenticular to spherical in outline.

RESULT: Germination of Pollen grain is observed through this experiment.

PRECAUTIONS:
➢ Flowers should be freshly plucked.
➢ Use clean slide to observe the pollen grains.
➢ Mounting should be free from air bubbles.
➢ Material should be moderately stained.

(THE DIAGRAM SHOULD BE DRAWN ON THE LEFT SIDE) GERMINATION OF POLLEN GRAINS
EXPERIMENT 2: STUDY OF PLANT POPULATION DENSITY BY QUADRATE METHOD.
AIM: To determine the population density of plants by quadrate method.
REQUIREMENTS: A field, plants to be studies in the field, string, nails, hammer, measuring tape and
record note book.
PRINCIPLE: Average number of particular plant species present per unit area is called as population
density.
PROCEDURE:
Plants in a field: Select a field and a plant species to be studied in it.
Quadrate:
➢ To make a quadrate, fix four nails A<B<C<D at a distance of 1 meter making a square of area 1
square meter.
➢ Tie a string around the nails to make boundary.
➢ The quadrate is ready. The size of the quadrate should be chosen as per the size and
frequency of the plant under study.
Counting:
➢ Count the plants under study lying inside the quadrate.
➢ If some plants fall on the boundary then includes only those is the quadrate which lay half or
more than half inside the quadrate.
Population density:
➢ Make the quadrate 4 to 5 times and count the plants in each.
➢ The sum total of plants in each quadrate divided by the number of quadrate will give the
population density of the plant.
OBSERVATION:
The following observation were made
Population density= Total number of plants in all the quadrates/Total number of quadrates.
Calculate the population density of the plants studied, per unit area using the formula given
above.
RESULT:
➢ No. of plant species studied in a quadrate are _____________
➢ Plant species with high density in the quadrate are _________ and species with less density
are _____
PRECAUTIONS:
➢ The field chosen for quadrate sampling should have almost uniform distribution of species
under consideration.
➢ One plant should be carefully counted once only.
➢ The plants coming in between the quadrate string should be included in it only if half or more
than half parts of the plant lies in the quadrate.
➢ Size of the quadrate should be chosen according to the size and frequency of the plant under
study.
(THE TABLE SHOULD BE WRITTEN ON THE LEFT SIDE)
TABULATION TO FIND PLANT POPULATION DENSITY.
S.N PLAN NO. OF INDIVIDUALS PER QUADRATE TOTAL NO POP
o T NO OF OF ULA
SPECI INDIVID QUD TIO
ES UALS RATE N
DEN
1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 SITY
0 1 2 3 4 5 6

1 A 4 2 1 2 1 4 1 1 3 6 2 7 2 4 0 0 46 16 2.8

2 B 0 3 0 1 0 0 0 1 1 1 0 8 0 0 0 0 15 16 0.9

3 C 6 5 4 1 2 3 3 1 7 0 1 2 2 2 2 1 42 16 2.6

4 D 0 0 0 2 1 1 2 0 1 2 1 2 0 1 1 0 14 16 0.87

5 E 0 0 2 0 0 0 0 0 0 0 0 0 0 0 2 2 6 16 0.37

6 F 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 16 0.06
EXPERIMENT 3: STUDY OF PLANT POPULATION FREQUENCY BY QUADRATE
METHOD.
AIM: To study plant population frequency by quadrate method.
REQUIREMENT: A field, plants to be studied in the field, string, nails, hammer, measuring tape and
record notebook.
PRINCIPLE: Total no. of quadrate having species in them among the total no. of quadrate gives the
percentile of population frequency.
PROCEDURE:
Plants in a field: Select a field and a plant species in a field. E.g: A
Quadrate:
➢ To make a quadrate, fix four nails A<B<C<D at a distance of 1 meter making a square of area 1
square meter.
➢ Tie a string around the nails to make boundary.
➢ Count the number of plant to be studied growing in the quadrate and record them.
➢ Repeat the above activity about 5 times making quadrate at different places in the field.
Population frequency: Calculate the population frequency as follows.
Population frequency= Sum of population density of plant species in all quadrate/Total number
of quadrates.
PRECAUTIONS:
➢ The field chosen for quadrate sampling should have almost uniform distribution of species
under consideration.
➢ One plant should be carefully counted once only.
➢ The plants coming in between the quadrate string should be included in it only if half or more
than half part of the plant lies in the quadrate.
➢ Size of the quadrate should be chosen according to the size and frequency of the plant under
study

(THE TABLE SHOULD BE WRITTEN ON THE LEFT SIDE)

TABULATION TO FIND POPULATION FREQUENCY
PLANT NUMBER OF INDIVIDUALS IN EACH QUADRATE FREQUENC
SPECIES Y

I II III IV V

1 3 4 3 4 5 3.8

2 6 5 3 1 5 4

3 3 6 0 7 9 5

4 5 4 2 3 1 3

5 6 3 2 0 2 2.6
EXPERIMENT 4: PREPARE A TEMPORARY MOUNT OF ONION ROOT TIP TO STUDY MITOSIS.
AIM: To prepare a temporary mount of onion root tip to study mitosis.
REQUIREMENTS: Onion root tips, slide, cover slip, flowers, aceto carmine stain, dissecting needles,
watch glass, water, blotting paper, methyl alcohol ,I N Hcl, acetic acid, spirit lamp, microscope etc.
PROCEDURE:
➢ Cut the root tips of onion and then transfer them to FAA fixative for 20-25 hours (acetic acid
1;3 ethanol).
➢ Transfer the root tips to the solution HCl : alcohol (1:1 ) for 20 min and then preserve them in
70% alcohol.
➢ Take one or two root tips from the preservative on a slide.
➢ Tease the root tips with the help of two needles.
➢ Add a few drops of acetocarmine and cover it with a cover slip.
➢ Warm it gently on a burner for a short while.
➢ Now put the slide between the folds of blotting paper.
➢ Press it firmly with your thumb to spread the material uniformly and for removing extra stain.
➢ Observe the slide under microscope, first in low power and then in high power.
➢ Draw and label the different stages of mitotic cell division.
OBSERVATION: Following stages are seen in onion root cells during cell division.
Interpase:
➢ It is a non dividing phase of the cell cycle between two successive cell divisions.
➢ Chromatin fibres appear in the form of a network within the nucleus.
➢ Nuclear envelop and nucleus are distinct.
Prophase:
➢ Chromatin material shortens and condenses into thread like structures called chromosomes.
➢ Each chromosome consists of two chromatids, jointed at a point called centromers.
➢ Nuclear membrane and nucleolus start disintegration and disappear at the end of prophase.
Metaphase:
➢ A bipolar spindle develops in the cell.
➢ Chromosomes become thick and two chromatids of each chromosome become clear.
➢ Chromosomes become arranged at the equator of the spindle.
➢ Each chromosome get attached to the spindle fibers at its centromere.
Anaphase:
➢ The two sister chromatids of each chromosome separate from the centromere and move
towards the opposite poles.
➢ The daughter chromosomes appear V,J,L and I shapes, depending upon the position of
centromere.
Telophase:
➢ The spindle disappears and the daughter chromosomes uncoil to form chromatin fibers at the
two poles.
➢ Nuclear membrane and nucleolus reappears and two daughter nuclei appear at opposite
poles.
➢ Cytokinesis occurs by cell plate formation between the two daughter nuclei.

RESULT: Various stages of mitosis have been studied.

PRECAUTIONS:
➢ The base of the onion bulb should be in contact of water while growing the roots.
➢ Root tips should be fixed in the morning between 8 to 1 am
➢ The slide should be warmed gently much above the flame of the sprit lamp

(THE DIAGRAM SHOULD BE DRAWN ON THE LEFT SIDE)

MITOSIS
EXPERIMENT 5: ISOLATION OF DNA FROM AVAILABLE PLANT MATERIAL
AIM: To isolate DNA from the available plant material
MATERIALS REQUIRED: Plant material (spinach, banana, orange, onion) salt, dish soap, alcohol,
mortar and pestle, glass beaker, cheese cloth, filter, microscope, slide, etc.
PROCEDURE:
➢ Fill a cup with (ethanol) alcohol and place it in the freezer about 30 minutes before beginning
the experiment.
➢ Peel the banana and cut it into small pieces.
➢ Put the banana pieces into a mortar and pestle.
➢ Add a teaspoon of salt, and then blend until a thick, easily pourable liquid is formed.
➢ Position the filter over a glass jar and pour the mixture into the filter with cheese cloth until
the jar fills about halfway. Remove the filter.
➢ Use regular dish soap. Add 2 tsp. of liquid dish soap to the jar and carefully stir it. Avoid
making bubbles.
➢ Remove the cold alcohol from the freezer and slowly pour it into the banana mixture, down
the side of the jar.
➢ Do not pour it directly into the center of the mixture.
➢ Use only enough alcohol to form a thin, separate layer on top of the banana mixture.
➢ Leave the mixture to stand for about 10 minutes, undisturbed.
➢ The DNA will coalesce and form a long white strand that will float to the top of the alcohol.
➢ Use a toothpick to pick it up and study it.
CONCLUSION:
➢ Pull out the stirrer and transfer the DNA to a piece of or clean tube.
➢ The fibers are thousands and millions of DNA strands.
➢ To view in a microscope, put the glob on a clean slide and gently tease/stretch a part using 2
toothpicks or dissecting pins.
➢ The fibers will be easier to see in the teased-apart area.
RESULT: Isolation of plant material has been studied.
PRECAUTIONS:
➢ Use freshly prepared source solution.
➢ Use enough amounts of chemicals.

(THE DIAGRAM SHOULD BE DRAWN ON THE LEFT SIDE)

ISOLATION OF DNA
EXPERIMENT 6: FLOWERS ADAPTED TO DIFFERENT POLLINATING AGENTS.

IDENTIFICATION: Anemophilous or wind pollinated flower-eg:Maize

COMMENTS:
➢ The maize plant is monoecious and bears unisexual flowers.
➢ The male flowers are borne in terminal inflorescence while
the female flowers are borne in axillary inflorescence.
➢ The flowers are colourless, odourless and nectarless.
➢ Flowers are small and inconspicuous.
➢ Both the stigma and anther are exerted.
➢ Anthers are versatile, and pollen grains are light, small and
dusty.
➢ Stigma is hairy, feathery or branched to catch wind borne
pollen grains.
➢ The pollen grains are produced in very large numbers.

IDENTIFICATION: Entomophilous or insect pollinated flower eg: Salvia

COMMENTS:
➢ The flowers are showy or brightly coloured for attracting pollinating Insects.
➢ Flowers secrete nectar to feed visiting insects.
➢ Nectar glands are placed in such a position that an insect must touch
both the anther and stigma.
➢ The flowers have landing platform for the insects.
➢ The flowers are protandrous with bilipped corolla and have turn pipe or
lever mechanism.
➢ Each stamen has long connective which bears a fertile anther lobe at the
upper end and sterile plate like anther lobe at the lower end.

IDENTIFICATION: Ornithophilous or Bird pollinated flower eg: Bignonia

COMMENTS:
➢ The flowers pollinated by birds are strong and or
adapted to allow the birds to stay near the flowers
without their wings getting entangled in them.
➢ The flowers are tubular and curled that facilitates
nectar sucking by birds.
➢ The flowers are odourless and bright coloured that
attracts the birds.
➢ While sucking the nectar the pollen gets deposited on
their beaks and neck and then transfer to the plant they
visit next.
EXPERIMENT 7: POLLEN GERMINATION ON STIGMA THROUGH A PERMANENT SLIDE.

IDENTIFICATION: Pollen germination on a slide.

COMMENTS:
➢ Pollen grain or microspore is the first cell of male gametophyte.
➢ Each pollen grain of a flowering plant (angiosperm) possesses two cells.
(1) Vegetative cell (2) Generative cell
➢ On the stigma, the pollen grain absorbs water and nutrients from the stigmatic secretion
through its germ pores.
➢ The tube cell gives rise to a pollen tube; the generative cell also descends into the pollen tube
and divides into two male gametes.
➢ There is only one pollen tube from one pollen.
➢ Certain pollen grains do not germinate and are referred as sterile pollens.

(THE DIAGRAM SHOULD BE DRAWN ON THE LEFT SIDE)

Pollen germination on a slide.

EXPERIMENT 8: GAMETE DEVELOPMENT
T.S OF TESTIS (OF MAMMALS)

IDENTIFICATION: The given slide is identified as T.S of Testis

COMMENTS:

➢ The mammalian testis is covered by a thick

fibrous tissue called tunica albuginea.
➢ The testis consists of numerous semniferous
tubules embedded in the interstitial tissue
➢ Various types of germinal cells are present
from outside towards lumen in the following
sequence.
Spermatogonia------ spermatocytes----- spermatids
spermatozoa------ sperms.
➢ Between the germinal cells, pyramid shaped
cells called sertoli cells are present.
➢ A large number of spermatozoa with their
heads embedded in sertoli cells are present in the
lumen of seminiferous tubule.
➢ The interstitial tissue also contains leydig cells, which produce male sex hormone testosterone.

T.S OF OVARY (OF MAMMALS)

IDENTIFICATION: The given slide is identified as T.S of ovary

COMMENTS:

➢ A mammalian ovary is a solid structure bounded by germinal epithelium followed by a thick

layer of fibrous tissue, the tunica albuginia.
➢ The ovary consists of outer cortex and inner
medulla.
➢ The medulla contains many rounded or oval
bodies called ovarian or graffian follicles at various
stages of development.
➢ The medulla also contains blood vessels,
nerves fibres and some smooth muscles.
➢ Each follicle contains a large ovum surrounded
by many layers of follicle cells.
➢ The cortex contains young and mature
follicles.
➢ The cortex may also contain a large mass of yellow cells termed corpus luteum, formed in an
empty graafian follicle after the release of its ovum.
EXPERIMENT 9: MEIOSIS IN ONION BUD CELL THROUGH PERMANENT SLIDES.
IDENTIFICATION: Meiosis in onion bud cells.
COMMENTS:
(A) Meiosis –I

(1)Prophase 1: It is slightly of longer duration and is different from prophase of mitosis. It can further
be subdivided into the following five sub stages –

(a) Leptotene:
➢ Chromatin fibres condense and form thick thread like structures called chromosomes.
➢ Nuclear envelope and nucleolus are distinct.
➢ The nucleus increases in size and volume by absorbing water.

(b) Zygotene:
➢ The two homologous chromosomes lie side by side. This is known as pairing or synapsis.
➢ Each pair of chromosome is known as bivalent.

(c) Pachytene:
➢ Each chromosome of a bivalent splits-longitudinally into two sister chromatids so that the
bivalent becomes a tetrad.
➢ Crossing over occurs in a homologous pair.
➢ The points of crossing over are known as chiasmata.

(d) Diplotene:
➢ As the chromosomes are showing gradual condensation so there is a tendency that chiasmata
tend to slip out of the chromosomes. This is known as terminalisation of chiasmata.
➢ Chromosomes start separating out but this paratition is not complete.
➢ Nuclear Membrane and nucleolus start degenerating.

(e)Diakinesis:
➢ Homologous chromosomes appear thick and ring shaped.
➢ Nucleolus and nuclear envelope disappear and spindle begins to be formed.

(2) Metaphase - I
➢ The bivalent arrange themselves at the equator of the spindle.
➢ The spindles get attached to the centromere of the chromosome.

(3) Anaphase - I
➢ The two chromosomes of each bivalent move to the opposite pole.
➢ Each pole has half the number of chromosomes with two chromatids each.

(4)Telophase – I
➢ The Chromosome at each pole uncoil, nucleolus and nuclear envelope reappear.
➢ Cytokinesis occurs to form two haploid daughter cells.
(B)Meiosis II: It includes following four stages.
(a)Prophase II
➢ The chromosomes of daughter cell begin to condense and become thick.
➢ Nuclear envelope and nucleolus begin to disappear.

(b)Metaphase II
➢ The chromosomes are arranged on the equator of the spindle.
➢ Nucleolus and nuclear membrane disappear.

(c)Anaphase II
➢ The sister chromatids of each chromosomes separate and migrate towards the opposite
pole.
➢ Each pole thus receives haploid number of chromosomes.

(d)Telophase II
➢ The chromosomes begin to uncoil and become thin.
➢ The nuclear envelope and nucleolus are reconstituted.

MEIOSIS IN ONION BUD CELL THROUGH PERMANENT SLIDES

EXPERIMENT 10: T.S. OF BLASTULA (MAMMALIAN)

IDENTIFICATION: The given slide is identified as T.S of blastula

COMMENTS:
➢ Blastula is a spherical mass of about 32 or 64 cells.
➢ It is composed of an outer envelope of cells, the trophoblast or trophoectoderm and inner cell
mass (embryoblast).
➢ Within the envelope there is a fluid filled cavity called blastocoele.
➢ The side of the blastocyst to which the inner cell mass is attached is called the embryonic or
animal pole, while the opposite side is the abembryonic pole.
➢ The inner cell mass is the precursor of the embryo.
➢ In this state it forms the connection with mother's uterus wall which is called implantation.
EXPERIMENT 11: MENDELIAN INHERITANCE

IDENTIFICATION: Mendelian inheritance

OBJECTIVE:
Study of Mendelian inheritance using seeds of different colour and size of any plant.

REQUIREMENTS:
Seeds of any plant (likepea), pencil, tray, eraser, notebook.

PROCEDURE:
➢ Collect the seeds of any plant (pea).
➢ Count the number of seeds which are yellow and green in colour.
➢ The ratios were analyzed on the basis of law of probability.
➢ Monohybrid cross can be shown by following cross.

OBSERVATION:
➢ Ratio of seed colour in plant in F1 generation is 100% yellow
➢ Ratio of seed colour in plant in F2 generation is 3:1

RESULT:
➢ Above ratio matches with the Mendelian ratio
EXPERIMENT 12: PEDIGREE ANALYSIS
IDENTIFICATION: The given chart is identified as pedigree of
Rolling of tongue
COMMENTS:
1. Autosomal recessive (aa) and not sexually inherited.
2. The rolling of tongue is the ability of a person to roll the
tongue in U shape.(AA,Aa)
3. The inability to roll the tongue is caused by an autosomal
recessive allele “a”(aa)
4. Thus both homozygous dominant ( AA) and heterozygous
dominant (Aa) able to roll the tongue.
5. While homozygous recessive (aa) individuals are unable to
roll the tongue.

IDENTIFICATION: The given chart is identified as pedigree of Widow Peak.

COMMENTS:
1. Autosomal dominant and not sexually inherited.
2. Widow peak is a V shaped hair line across the forehead.
3. It is a dominant trait.
4. Thus both homozygous dominant AA and heterozygous Aa
individuals have widow peak, while homozygous recessive aa
individuals have straight hairline.
5. In the pedigree given below indicate whether the shaded
symbols belong to dominant or recessive trait.

IDENTIFICATION: The given chart is identified as pedigree of Colour blindness.

COMMENTS:
➢ Colour blindness of red and green colour is a sex
linked disease caused due to the presence of defective
gene on X chromosome.
➢ As the Y chromosome present only in males (XY)
carries genes related with sex only it does not have any
allele for colour blindness on it hence the male are
mostly affected by this disease.
➢ In females there are two X chromosomes, so if one
is defective it is hidden by the normal X chromosomes.
So the females suffer only when both XX defective.
IDENTIFICATION: The given chart is identified as pedigree of Earlobe.
COMMENTS:
➢ The presence of an attached ear lobe is due to a recessive autosomal allele pair or gene
and the presence of free earlobe is due to a
dominant gene
➢ In the adjoining pedigree , it is observed that in
the first generation person 1 grandpa and person
2 grandma have free earlobes therefore
genotypically both of them have a dominant
allele for this characteristic (heterozygous) .
➢ In the next generation it is seen that one of their
sons has attached earlobes making
him homozygous recessive( ie .ff) and indicating
that both the persons of first generation
(ie.Grandma and grandpa) were heterozygous
(ie.Ff)

IDENTIFICATION: The given chart is identified as pedigree of Blood group.

COMMENTS:
➢ The pedigree chart shows Autosomal
Codominant blood grouping
➢ The pedigree chart shows the cross between
blood group A,B and O
➢ The possibilities of blood group of offsprings
AO and BO-1
➢ If the cross takes place between A and O
blood group the offspring produced by the
couple may be O group or A group
➢ If the cross between BO with A then the off
spring may be AB, O, A.
EXPERIMENT 13: CONTROLLED POLLINATION- EMASCULATION, BAGGING, TAGGING
IDENTIFICATION: Controlled pollination.
A. Emasculation:
➢ In this process anthers are removed from the flowers before their maturation.
➢ The anthers are cut with the help of sterilized forceps or scissors.
➢ The Instrument used in this method-include Pocket lens, forceps, needle, scissors, scalpe letc.
➢ Method of emasculation is employed to the crops having small flowers like paddy.
B. Bagging and tagging:
➢ After emasculation, the flowers are covered with small bags to prevent pollination with
undesired pollen grains.
➢ These bags are made up of polythene paper, muslin cloth or parchment paper.
➢ The flowers of male parents are also protected in bags to prevent mixing of their pollen grain
with foreign pollens.
➢ After dusting of the desired pollen grains on the emasculated flowers. The bags are retagged.
➢ A label of paper is tagged on the plant which displays the date of emasculation, crossing and
brief account of the parents.

EMASCULATION

BAGGING AND TAGGING

EXPERIMENT 14: COMMON DISEASE CAUSING ORGANISM
IDENTIFICATION: The given slide is identified as Entamoeba histolytica (Anaerobic parasitic
amoebozoan)
NAME OF THE DISEASE: Amoebiasis or Amoebic dysentery
SYMPTOMS:
• Abdominal pain
• Repeated motion with blood and mucus
COMMENTS:
➢ It is a human parasite that resides in the upper part of the large intestine.
➢ It causes the disease called amoebic dysentery
or amoebiasis.
➢ The symptoms of the diseases include
abdominal pain, repeated motions with blood
and mucus.
➢ The parasite is unicellular and has a blunt
pseudopodium.
➢ There is a single nucleus and a number of food
vacuoles.
➢ It feeds on red blood corpuscles by damaging
the wall of large intestine and reaching the
blood capillaries.
➢ It produces ulcers and can also reach other body
organs.

IDENTIFICATION: The given slide is identified as Plasmodium vivax (Malarial parasite)

NAME OF THE DISEASE: Malaria
SYMPTOMS: Fever appears about 14days after infection.
COMMENTS:
➢ It is a protozoan digenic endoparasite of man.
➢ Its primary host is man and female anopheles is its
secondary host.
➢ Plasmodium enters human body in sporozoite stage by the
bites of female anopheles.
➢ The sporozoite is spindle shaped and uninucleate organism
capable of wriggling movement.
➢ The sporozoites infect liver cell and produce meta-
cryptomerozoites.
➢ The metacryptomerozoites enter RBCs, and passes trophozoite signet ring stage and
amoeboid stage and produce schizont and merozoites.
➢ The merozoites enter fresh RBCs and produce gametocytes.
IDENTIFICATION: The given slide is identified as Ascaris lumbricoides

NAME OF THE DISEASE: Ascariasis

SYMPTOMS: Abdominal discomfort, impaired digestion, diarrhoea and

vomiting.

COMMENTS:
➢ It is an endoparasite of the small intestine of human beings and
is more common in children.
➢ The animal shows sexual dimorphism with separate male and
female individuals.
➢ The life history is simple and without any intermediate host. The
infection occurs through contaminated food and water.
➢ Ascaris causes abdominal discomfort and colic pain.
➢ The patient may also suffer from impaired digestion, diarrhoea and vomiting.
➢ In children mental efficiency is affected and body growth is retarded.

IDENTIFICATION: The given slide is identified as Trichomonas sps

NAME OF THE DISEASE: Ring worm

SYMPTOMS: Itchy skin, ring shaped rash, red scaly cracked skin, hair loss.

COMMENTS:
➢ It forms lesions on hairy parts of smooth skin.
➢ It also infects the nails of the hands and feet.
➢ Some species of these fungi cause ring worm of the
scalp found chiefly in children.
➢ Mostly they infect the skin so this fungi and disease
are called dermatomycoses.
➢ Skin becomes dry and whitish in colour with keratin
substances.
EXPERIMENT 15: SYMBIOTIC ASSOCIATION IN ROOT NODULES OF LEGUMINOUS PLANTS, CUSCUTA ON
HOST, LICHENS
OBJECTIVE:
To study symbiotic association in root nodules of leguminous plant, cuscuta on host and
lichens through model/specimen/chart

REQUIREMENTS:

Model/ specimen/ chart showing symbiotic association in root nodules of leguminous plant
(pea plant), cuscuta on host and a lichen.

THEORY:

➢ In nature animals, plants and microbes do not and cannot live in isolation but interact in
various ways.

➢ When two different species interact with each other (Inter specific interaction) and are in
close association with each other in such a way that atleast one species is benefited while for
other species the relationship may be positive, negative or neutral such association is called
symbiotic relationship.

➢ There are three basic types of symbiotic relationship

• Mutualism (both are benefited)

• Commensalism (one species is benefited while other is neither benefited nor harmed)

• Parasitism (one species is benefited and other is harmed)

 RHIZOBIUM IN ROOT NODULES OF LEGUMINOUS PLANT (PEA PLANT)
OBSERVATIONS:
➢ Rhizobium bacteria are
present in root nodules of
leguminous plant and form a
symbiotic relationship,
mutualism, where both are
benefited from each other.
Nitrogen fixing bacteria like
Rhizobium fixes atmospheric
nitrogen into nitrogenous
compounds.
➢ Rhizobium can convert atmospheric nitrogen to ammonia that can be used by pea plant for
growth and development.
➢ Bacteria receive nutrients and suitable place to grow from plant.

CUSCUTA WITH HOST

OBSERVATIONS:
➢ Cuscuta commonly called dodder or
amerbel and live as stem ectoparasite on
other plants.
➢ Cuscuta has no fully expanded form of
leaves (scale like leaves are present) and
has no chlorophyll.
➢ Stem of cuscuta is thin and slender
shaped and it winds around the stem of
host plant. Stem of cuscuta fixes itself to
the stem of host plant with special
structures called Haustoria. Haustoria forms direct connection to the vascular bundles of the
host and with draw water, carbohydrates and other solutes.
➢ Roots of cuscuta are temporary and die as soon as it makes connection with host plant.
➢ Cuscuta can weaken or kill plant and reduce crop yield.

LICHENS
OBSERVATIONS:
➢ Lichens are composite organisms representing a
symbiotic association (mutualism) between fungus
and algae.
➢ The algal component is known as phycobiont and
fungal component is known as mycobiont.
➢ Algae prepare food for fungi and fungi provide shelter
and absorb mineral, nutrients and water for its
partner.
➢ They grow on lands, rocks, tree trunks and walls of
houses, like dry vegetation.
EXPERIMENT 16: HOMOLOGOUS AND ANALOGOUS ORGANS IN PLANTS AND ANIMALS

AIM:
Study of homologous and analogous organs in plants and animals.

PRINCIPLE:

In plants and animals there are several organs or parts thereof, apparently alike in their
function and appearance, but markedly different from each other in their origin and anatomical
structure. These organs are called analogous organs, and the seeming similarity among them is
the result of convergence, that is, adaptation to similar habitat and identical ecological niche.

On the other hand, there are organs or parts thereof, which apparently are quite dissimilar to
each other in appearance and perform different functions, but have the same origin and
anatomy. The differences in their function and also in their appearances are the result of
divergence, due to adaptive radiation to different habit, habitat and ecological niche. These
organs are called homologous organs.

REQUIREMENT:
➢ Plant specimens showing tendrils, thorns
➢ Plant with normal stem, potato and onion bulb, prickly pear
➢ Specimens of phylloclade, cladode,
➢ Wings of bird, cockroach and bat and cervical, thoracic and lumbar vertebrae of a
mammal /lizard.

OBSERVATIONS:
HOMOLOGOUS ORGANS IN PLANTS

Tendrils of passion flower and thorns of

pomegranate:

Tendrils of passion flower and thorns of

pomegranate are structurally and functionally
different but they have similar origin i.e. they
arise from axillary bud.
Tendrils of Vitis and thorns of Carissa:

Tendrils of Vitis and thorns of Carissa

originate from the terminal bud,
but they are functionally different.

Tendrils of balloon vine (Cardiospermum)

and bulbils of Agave.
Tendrils of balloon vine (Cardiospermum)
and bulbils of Agave both are modifications
of floral bud, but they perform different functions.
Tendrils help in climbing but bulbils are
meant for reproduction.

Scale leaves of onion and spines of prickly pear (Opuntia)

Both the scale leaves and spines are modifications of leaves but are structurally and functionally
different. Scale leaves of onion are thick and fleshy and store food. On the other hand spines of
cactus are defensive organs.

ANALOGOUS ORGANS IN PLANTS

Stem tendrils and leaf tendrils
All tendrils are analogous with one another,
being structurally and functionally similar,
irrespective of their origin.
Example: Tendrils of pea and tendrils of Vitis.
Tendrils of pea are modification of leaf and in
Vitis it is the modification of terminal bud.

Thorns and spines

Thorns and spines are analogous

structures being defensive in function.

Thorns are modifications of axillary or

terminal buds, and spines are
modifications of leaves.

E.g: Thorns of pomegranate and spines of

prickly pear.

Modified underground stems and modified roots

Modified stems (rhizome, corm, and 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 is stems and beetroot, radish etc. are roots.

Phylloclade, Cladode and leaves

They perform the same function i.e they photosynthesise but phylloclade and cladode are
modifications of stem. Phylloclade of Opuntia, Parkinsonia, Asparagus and leaves of any local plant
like mango are analogous organs.

HOMOLOGOUS ORGANS IN ANIMALS

Wings of birds, and forelimb of mammals/ reptiles/ frog:
All have the same bony elements (humerus radius, ulna, carpals, metacarpals and phalanges), but
perform different functions (flying in birds, for holding or walking etc. in other).

ANALOGOUS ORGANS IN ANIMALS

➢ Wings of dragonfly/ cockroach/ butterfly and of birds.

➢ Mandible of cockroach and mandible (lower jaw) of a vertebrate.