Biology NCERT Class XII

Content

  • Chapter 1 – Reproduction in Organism
  • Chapter 2 – Sexual Reproduction in Flowering Plants
  • Chapter 3 – Human Reproduction
  • Chapter 4 – Reproductive Health
  • Chapter 5 – Principles of Inheritance and Variation
  • Chapter 6 – Molecular Basis of Inheritance
  • Chapter 7 – Evolution
  • Chapter 8 – Human Health and Disease
  • Chapter 9 – Strategies for Enhancement in Food Production
  • Chapter 10 – Microbes in Human Welfare
  • Chapter 11 – Biotechnology: Principles and Processes
  • Chapter 12 – Biotechnology and its Applications
  • Chapter 13 – Organisms and Populations
  • Chapter 14 – Ecosystem
  • Chapter 15 – Biodiversity and Conservation
  • Chapter 16 – Environmental Issues

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Test for glucose, sucrose, proteins, fats & shows their presence in suitable plant & animal materials

AIM: To test for glucose, sucrose, proteins, fats & shows their presence in suitable plant & animal materials (e.g. – wheat, potato, groundnut, milk or other materials)

REQUIREMENTS: Wheat grain, potato, groundnut, milk, egg, grapes/apple/banana, filter paper, test tubes, funnel, beaker, burner, Benedict’s solution, Fehling’s solutions, Biuret reagent, Million’s, Sudan III, NaOH, HCl, HNO3 etc.

PROCEDURE: Soak the suitable material (wheat, groundnut or rice). Grind them separately & make their paste. Similarly make a paste of potato, fruits & egg album in separately. Filter the content of all these in separate test tubes & label them. Use these filtrates for testing.

TEST OBSERVATION INFERENCE
1.TEST FOR GLUCOSE

(i) BENEDICT’S TEST

Take 2ml of fruit juice in a test tube. Add 2ml of Benedict’s solution to it. Boil test tube for 2 minutes & cool.

(ii) FEHLING’S TEST

Take 2ml of fruit juice in a test tube & add 2ml of each of Fehling’s solution A & Fehling’s solution B in it & boil.

A green ppt appears in the solution, which may later turn orange or brick red in colour

Orange or brick red ppt. appears in the test tube.

Shows the presence of glucose. Green ppt shows presence of glucose in lesser concentration, orange or red ppt indicate the presence in higher concentration.

Shows presence of glucose (Monosaccharide)

2. TEST FOR SUCROSE

Take 2ml of sugar cane juice. Add a few drops of HCl & boil the test tube gently for one or two minutes. This hydrolyses sucrose into glucose & fructose. Make the solution alkaline with NaOH. Now perform Benedict’s or Felling’s test with this solution for presence of glucose

Orange or brick red ppt is observed in the test tube. Positive test with Benedict’s/ Ferling’s solution shows the presence of sucrose in juice tested.
3. TEST FOR STARCH

(i) IODINE TEST

Take 2ml extract (potato/gram/rice) in a test tube & add a few drops of iodine solution to it.

(ii)BENEDICT’S/FEHLING’S

Test after hydrolysis. Take 2ml of starchy solution. Hydrolyse it by boiling with a few drops of HCl. Make the solution alkaline by adding NaOH & perform Benedict’s/Fehling’s test.

Blue-black colour is observed.

Brick red or orange ppt is observed.

Shows the presence of starch.

Positive test with Benedict’s solution shows the presence of starch.

4. TEST FOR PROTEINS

(i) BIURET TEST

Take 3ml of 5% NaOH in a test add 2 drops of 1% CuSO4. Shake it thoroughly now in a 2nd test tube take 2ml of the extract (grapeseed)

(ii) XANTHOPROTEIC TEST

  1. Take 2ml of the extract in a test tube & add 2-3 drops of concentrated HNO3 to it
  2. Cool the solution, dilute it with H2O & add few drops of ammonia

MILLON’S TEST


Take 2 ml of the extract in attest tube & add 2ml of Millon’s reagent to it.

Pink, red or violet colour is observed.

Yellow ppt observed.

Yellow ppt changes to orange.

Rink or red colour is seen.

Show presence of proteins.

Indicates the presence of protein

 

Protein indicated

5. TEST FOR FATS

(i) Take a 1 ml of extract (peanuts/castor seeds) in a test tube & shake the solution vigorously. Dip a glass red in the solution & put its spot on the white paper.

(ii) Crush peanut/ castor seed & rub it on a piece of white paper.

(iii) Take 2ml of the extract in a test tube & add 1ml of Sudan III to it.

Paper becomes translucent at the spot.

A translucent spot appears the paper.

Pink droplets appear in the solution.

Indicates presence of fat

Indicate presence of fat.

Shows presence of fat.

This website also contains other Class XI Practicals on BiologyPhysics, and Chemistry.

Study Of Character Of Plant Specimens And Identification With Reasons

Study Of Character Of Plant Specimens And Identification With Reasons

AIM: Study of character of : Spirogyra, Rhizopus, Mushroom/Bracket fungi, Liver wort, Moss, Fern, Pinus, One Monocotyledon, One Dicotyledon, Yeast & lichens.

REQUIREMENTS: Prepared slides or preserved specimens, record file, pencil, a laboratory guide etc

AGARICUS (MUSHROOM)

Classification:-

  • Kingdom – Fungi
  • Division – Eumycophyta
  • Class – Basidiomycetes
  • Genus – Agaricus
  • Species – Compestris

Agaricus

COMMENTS: It is a saprophytic fungus that grows in hum & rich soils piles of straw & rotting wooden logs

It has septate mycelium under the substratum. The mycelium produces white & creamy coloured umbrella shaped ‘ fruit bodies’ or ‘basidiocarp’ above the substratum.

Pileus is circular, umbrella like & bear a number of vertical plate like structure called gills.

DIAGNOSTIC FEATURES: The fruiting body is umbrella shaped

Gills are present on the lower side of the pileus

SACCHAROMYCES (YEAST)

Classification:-

  • Kingdom – Fungi
  • Division – Eumycophyta
  • Class – Ascomycetes
  • Genus – Saccharomyces sp.

Saccharomyces

COMMENTS: It is commonly found growing in sugary medium such as fruit surface, nectar, cane juice etc

It is unicellular but may form a ‘pseudomycelium’ by repeated budding

Yeast cell is oval or elliptical in shape with a distinct cell wall made up of chitinous material

Volutin granules & glycogen droplets are present as reserve food in cytoplasm

DIAGNOSTIC FEATURES : Unicellular

Presence of nuclear vacuole

Reproduction by budding

RICCIA (LIVERWORT)

Classification :-

  • Kingdom – Plantae
  • Division – Bryophyta
  • Class – Hepaticeae
  • Genus – Riccia

Riccia

COMMENTS: The plant body is a dorsoventrally flattered & dichotomously branched thallus. It may form a rosette due to repeated dichotomous branching of thallus

Scales and rhizoids are present on the ventral surface. Scales protect the growing apex and retain moisture

Rhizoids are unicelluclar, colourless and tabular. They help in anchorage & absorption

The thallus represents haploid gametophytic stage

DIAGNOSTIC FEATURES: Plant body is a thallus with repeated dichotomous branching

Sex organs & sporophyte embedded in the thallus

FUNARIA HYGROMETRICA (MOSS)

Classification:-

  • Kingdom – Plantae
  • Division – Bryophyta
  • Class – Musci
  • Genus – Funaria
  • Species – Hygrometrica

Funaria Hygrometrica

COMMENTS: The plant body is gametophyte. It is green, erect & is differentiated into rhizoids, axis (stem) & leaves

Rhizoids are multicellular and branched with oblique septa

The main axis is erect and bears spirally arranged lenses

Sporophyte is differentiated into foot, seta & capsule

DIAGNOSTIC FEATURES: Gametophyte is represented by a filamentous protonema & adult leafy gametophyte

Rhizoid branched and obliquely separate

Sporophyte is a partial parasite upon the gametophyte

DRYOPTERIS (MALE FERN)

Classification:-

  • Kingdom – Plantae
  • Division – Pteridophyta
  • Class – Filicinae
  • Genus – Dryopteris

Dryopteris

COMMENTS: The plant body is sporophyte & is differentiated into root, stem (underground rhizome) & pinnately compound leaves

The young leaves have circinate ptyxis & are covered with hair called ramenta

The spores are haploid which give rise to heart shaped membranous gametophyte called prothallus

DIAGNOSTIC FEATURES: Stem is rhizome

Young leaves have circinate ptyxis & bear rementa

Leaves pinnate with furcate venation

PINUS ROXIBURGHI (CHIR)

Classification:-

  • Kingdom – Plantae
  • Division – Spermatophyte
  • Class – Gymnospermae
  • Genus – Pinus
  • Species – Roxburghii

Pinus Roxburghii

COMMENTS: Stem is covered with bark & bears types of branches long shoots and dwarf shoots. The long shoots bear scale leaves & grow indefinitely by apical bud, whereas dwarf branches bear scale leaves & foliage leaves are of limited growth.

Pinus tree is monoecious & bears both male & female cones

The plant body is sporophyte. Differentiated into root, stem & leaves.

DIAGNOSTIC FEATURES: Evergreen, woody, perennial tree

Seeds are naked

Presence of long shoots & dwarf shoots

Reproductive organs are cones

DICOTYLEDONOUS PLANT

  • BRASSICA CAMPESTRIS

Classification:-

  • Kingdom – Plantae
  • Division – Spermatophyta
  • Class – Angiospermae
  • Sub class – Dicotyledonous
  • Species – Campestris

Brassica Campestris

COMMENTS: Stem is soft green with distinct nodes & internodes

The leaves are alternate sessile, simple with lobed margin & reticulate venation

It bears colour yellow flower for reproduction. Each flower is bisexual & bimerous with cruciform corolla

DIAGNOSTIC FEATURES: Tap root system

Leaves with reticulate venation

Binerous flowers

Seeds are enclosed in fruits

Embryo with two cotyledons

MONOCOTYLEDONOUS PLANT

  • SPHODELOUS TENEUFOLIUS (PIAZI)

Classification:-

  • Kingdom – Plantae
  • Division – Spermataophyta
  • Class – Angiospermae
  • Sub class – Dicotyledonae
  • Genus – Sphodelous
  • Species – Teneufolius

Piazi

COMMENTS: It bears adventitious root system

Leaves are bone in cluster. Each leaf is cylindrical, hollow &has parallel variation

The seed enclosed an embryo with only one cotyledon

DIAGNOSTIC FEATURES: Adventitious root system

Leave with parallel venation

Flowers trimerous

Seeds enclosed in fruits

Embryo with one cotyledon

LICHENS A SYMBIOTIC ASSOCIATION)

Lichens are composite organisms representing a symbolic association between a fungus & an alga

Lichens grow on lands, rocks, tree trunks & walls of houses, like dry vegetation

The thallus of lichen resembles neither alga nor fungus

In a lichen thallus the algae individual called mycobiant belongs to ascomycetes or basidiomycetes

Phycobient belongs to chlorophyceae or mynophycaea

Lichen reproduces vegetatively by fragmentation, asexually by soredia & isidia

Sexual organs like those in Ascomycates are formed

This website also contains other Class XI Practicals on BiologyPhysics, and Chemistry.

Study Of Characters Of Animal Specimens And Identification With Reasons

Study Of Characters Of Animal Specimens And Identification With Reasons

AIM: Study of characters of specimen and identification :-
Amoeba, Fasciola Hepatica (Liver Fluke), Round worm (Ascaris Lumbricoides), Hirudinaria (Leech), Pheretima Posthuma (Earthworm), Palaemon (Prawn), Bombyx Mori (Silk worm), Pila Globosa (Apple Snail), Asteria (Star Fish), Scoliodon (Dog fish/ Shark ), Hydra, Starfish, Frog, Labeo Rohita (Rohu), Pigeon, Rabbit.

REQUIRED: Fresh or preserved animal specimens, record file, pencil, eraser, sharper, rules, a laboratory guide or practical file.

AMOEBA PROTEUS

Classification:-

  • Kingdom – Protista
  • Phylum – Protozoa
  • Class – Sarcodine
  • Order – Amoebida
  • Genus – Amoeba
  • Species – ProteusAmoeba Proteus

COMMENTS: Amoeba occurs in ponds, ditches lakes, streams etc, having plenty of decaying organic matter.

It is unicellular, microscope, grayish in colour and is about 0.2 to 0.5 mm in diameter.

Under the microscope, a living Amoeba appears like an irregular jelly like, tiny mass of hyaline protoplasm. The protoplasm can be distinguished into an outer octoplasm & inner endoplasm.

Diagnostic Features: Unicellular & irregular shape of the shape.

Presence of finger like & blunt pseudopodia.

Presence of contractive vacuole

FASCIOLA HERPATICA (LIVER FLUKE)

Classification:-

  • Kingdom – Animalia
  • Phylum – Platyhelminthes
  • Class – Trematoda
  • Order – Echinostoma
  • Genus – Fasciola
  • Species – Hepatica

Liver Fluke

COMMENTS: It is an endoparasite found in the bile ducts of sheeps, goats, cattles, sometimes other vertebrates excluding man.

It causes serious liver diseases called liver rot.

It is somewhat triangular, flat, leaf like parasite about 25mm in length. It has an oval and ventral sucker (acetabullum) used to adhere to the bile duct.

The body is covered by cuticle with spinules.

DIAGNOSTIC FEATURES: The body is triangular & leaf like

Body is covered with cuticle

Presence of two suckers

ASCARIS LUMBRICOIDES (ROUND WORMS)

CLASSIFICATION:-

  • Kingdom – Animalia
  • Phylum – Nemathelminthes
  • Order – Ascaroidea
  • Genus – Ascaris
  • Species – Lumbrecoides

Ascaris Lumbrecoides

 

 

 

 

 

COMMENTS: It’s a common intestinal parasite of a man especially children. Occasionally it may occur in the intestine of pig, sheep, cattle etc.

It has a cylindrical body with tapering ends. The front ends of the body have a terminal triradiate mouth surrounded by three lips.

A little behind anterior end, there is a small excretory pore.

DIAGNOSTIC FEATURES:

Endoparasite

Body covered with cuticle

Mouth guarded by three lips

Elongated body with tapering ends

HIRUDINARIA GRANULOSA (LEECH)

Classification :-

Kingdom – Animalia
Phyllum – Amelida
Class – Hirudiniaria
Order – Grathobdellida
Genus – Hirudinaria
Species – Granulosa

Hirudinaria
COMMENTS: It’s found in ponds, lakes, rivers, swamps and in moist soil near them

It’s a facuttative ectoparsite of cattle and other mammals. It sucks blood (saguinious) by periodically coming in contact with the host body.

Its body is somewhat dorso- vertically flattered and measures about 15 cm in length but it can stretch its length upto 30 cm when required. It is olive green in colour.

DIAGNOSTIC FEATURES: Slimy, elongated & segmented body

Presence of anterior & posterior suckers

PHERETIMA POSTHUMA (EARTHWORM)

Classification :-

  • Kingdom – Animalia
  • Phylum – Amelida
  • Class – Oligochaetra
  • Order – Terricelae
  • Genus – Pheretima
  • Species – Posthuma

 

Pheretima

COMMENTS: The segments 14th, 15th & 16th form a band called clitellum. It focuses one or more egg cases or cocoons in which ova are laid & fertilized.

Mouth is present at the anterior end. A fleshy lobe called prostomium dorsally over hangs upon the mouth like a hood. Anus is preset in the last segment.

Each segment except the first & the last bears row of minute yellowish setae for locomotion.

DIAGNOSTIC FEATURES: Elongated cylindrical & segmented body

Presence of prostomium & clitellum

Earthworm has setal for locomotion,

PALAEMON (PRAWN)

Classification :-

  • Kingdom – Animalia
  • Phylum – Arthropoda
  • Class – Crustaceae
  • Order – Decapoda
  • Genus – Palaemon
  • Species – Malcolmsonii

COMMENTS : The body is curved & is almost 5 to 18 cm long. It is distinguished into cephalothorax & a long abtomer. The cephalothorox is dorsally covered by a hard carapa which extends as a serrated process called rostrum. Cephalothorax bears eight pairs of segmented legs & on a pair each anterrae, anterrrules & stalked compound eyes.

DIAGNOSTIC FEATURES: Brown coloured spindle shaped & curved body

Abdomen six segmented

Cephalothorax is covered by a carapace with serrated rostrum.

BOMBYX MORI (SILKWORM)

Classification :-

Kingdom – Animalia
Phylum – Arthropoda
Class – Insecta
Order – Lepidoptera
Genus – Bombyx
Species – Mori
Life Cycle of Mammoth

 

 

COMMENTS:Adult silk moth is about 25cm long with two pair of wings. It is creamy white in colour

The body is divisible into head, thorax & abdomen & is covered by minute scales.

The larva undergoes four months & then stop feeding. It secretes a sticky fluid through its spinnerets, which on coming in contact with air becomes silk thread & remains wrapped around its body to form pupa

DIAGNOSTIC FEATURES:

Body is divisible into head, thorax & abdomen

Larva form cocoon

Presence of two pairs of wings & three pairs of legs

BOMBYX MORI (SILK WORM):

Classification:-

  • Kingdom – Animalia
  • Phylum – Arthropoda
  • Class – Insecta
  • Order – Lepidoptera
  • Genus – Bombyx
  • Species – Mori

COMMENTS:

Adult silk moth is about 2.5 cm long with two pairs of wings. It is creamy white in colour.

The body is divisible into head, thorax & abdomen & is covered by minute scales

The larva undergoes four months & then stop feeding. It secretes a sticky fluid through its spinnerets, which on coming in contact with air becomes silk thread & remains wrapped around its body to form pupa

DIAGNOSTIC FEATURES

Body is divisible into head, thorax & abdomen

Larva form cocoon

Presence of two pairs of wings & three pairs of legs

PILA GLOBOSA (APPLE SNAIL)

Classification :-

  • Kingdom – Animalia
  • Phylum – Mollusca
  • Class – Gastropoda
  • Order – Prosobranchiata
  • Genus – Pila
  • Species – Globosa

Pila Globosa

COMMENTS: It has a soft & slimy body enclosed in a coiled calcareous shell. The opening of the shell is closed by a thick plate like operculum.

The body is differentiated into head, foot, visceral mass & mantle

Sexes are separate with slight sexual dimorphism

DIAGNOSTIC FEATURES: Skell is univalved & coiled

Foot is muscular & board

Head distinct with eyes & tentacles

ASTERIAS (STAR FISH)

Classification:-

  • Kingdom – Animalia
  • Phylum – Echinodermata
  • Class – Asterioda
  • Order – Forcipulata
  • Genus – Asterias
  • Species – Rubers

Asterias

COMMENTS: The oral surface directed downwards & bears pentagonal mouth in the central disc

Sexes are separate without sexual dimorphism

Aboral surface bears large number of short & movable spines. Anus is present in the centre of the disc.

DIAGNOSTIC FEATURES: Body pentagonal & star shaped

Each arm with four rows of tube feet

Oral & aboral surfaces are quite distinct

SCOLIDON (SHARK/DOG FISH)

Classification:-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Subphylum – Vertebrata
  • Class – Chondrichthyes
  • Genus – Scoliodon sp.

Scoliodon

COMMENTS: It has somewhat laterally compressed & spindle shaped or streamlined body with painted snout

The body is differentiated head, Trunk & tail.

Sexes are separate. Sharks are viviparous

Two mid dorsal, one mid ventral, one caudal & two pairs of lateral fins are present.

LABEO ROHITA (ROHU)

Classification :-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Sub-phylum – Vertebrata
  • Class – Osteichthyes
  • Genus – Labeo
  • Species – RohitaLabeo Rohita

COMMENTS: It is a fresh water dweller commonly called rohu fish, widely used as food.

Mouth is sub- terminal & ventral. A pair each of nostrils & large lateral eyes without eyelids

There are five gills slits covered by operculars

It measures 80-90cm in length. It is covered with overlapping cycloid scales.

RANA YIGRINA (FROG)

Classification:-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Sub-Phyllum – Vertbrata
  • Class – Amphibia
  • Order – Anura
  • Genus – Rana
  • Species – Tigrina

Rana Tigrina

COMMENTS: It has somewhat triangular, bilaterally symmetrical, body with head & trunks.

The skin is dark green with black patches, moist & is covered by mucus.

Eyes bulging out without eyelid. Underwater, eyes are protected by their membrane called nictitating membrane.

Sexes are separate. Development is indirect

ORYTOLAGUS CUNICULUS (RABBIT)

Classification:-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Sub phylum – Vertebrata
  • Class – Mammalia
  • Order – Lagomorpha
  • Genus – Oryctolagus
  • Species – Cuniculus

Oryctolagus Cuniculus

COMMENTS: It’s a body is divided into head, neck & trunk & small bushy tail. The body is covered with hair of white brown or black colour

Two largely movable pinnae present behind eyes. The eyes are pink in colour

The mouth is bounded by soft & fleshy upper & lower lips

Sexes are separate with sexual dimorphism

Females have mammary glands with nipples in the abdomen

HEMIDACTYLUS (WALL LIZARD)

Classification:-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Sub – Phylum – Reptilia
  • Order – Lacertilia
  • Genus – Hemidactylus sp.

Hemidactylus

COMMENTS: Its body is 8-14 cm long, brown in colour & is distinguished into thick & flattered head, short, neck, large trunk & a tapering tail.

The head has pairs of eyes with movable eyelids, nostrils, & ear opening.

The skin is dry, covered with minute scales. The tail with annular pores of scales, which can be scales that can be broken off.

Limbs four in number, each with five clawed digits

COLUMBA LIVIA (PIGEON)

Classification :-

  • Kingdom – Animalia
  • Phylum – Chordata
  • Sub phylum – Vertebrata
  • Class – Aves
  • Genus – Columba
  • Species – Livia

Columba Livia

COMMENTS: Its body is 20 to 25 cm long & covered with slate blue feathers

It has a subspherical head, mobile neck, thick trunk & short tail.

The eyes are red in colour.

The beak is small & slightly curved in front

 

HYDRA

Classification :-

  • Kingdom – Animalia
  • Phylum – Crideria
  • Class – Hydrozoa
  • Order – Hydrozoida
  • Genus – Hydra
  • Species – Vulgaris

Hydra

COMMENTS: The body consists of an elongated tube with closed base & single opening at oral end.

Body wall consists of two layers of cells (Diploblastic)

Epidermis consists of stinging cells or cnidocytes to act as organ of defence & offence

DIAGNOSTIC FEATURES: Soft bodies & diploblastic

Body is elongated & saclike

Presence of tentacles & stinging cells

This website also contains other Class XI Practicals on BiologyPhysics, and Chemistry.

Studying the pH and water holding capacity of different soil samples

AIM: To study the pH and water holding capacity of different soil samples

REQUIRED: Soil samples, measuring cylinders, funnel, filter paper and pH indicator.

PROCEDURE: Take two funnels and line them with filter paper.

Put these funnels in a measuring cylinder

Put the two soil samples in separate funnels

The weight of soil sample should be same in both (25g)

Pour equal amount of water in both funnels (25ml)

Let the water drip in the cylinder

Note the volume of water collected

Test the two samples with pH indicator and note the observations.

OBSERVATIONS: The volume of water collected in cylinder of sample A was more than sample B

CALCULATIONS: The volume of water retained = Volume of H2O collected in cylinder.

water holding capacity equation

CONCLUSION: Soil sample A is roadside soil and sample B is garden soil at sample B has more water holding capacity.

PRECAUTIONS: Water should be poured slowly

The measuring cylinder should be properly calibrated.

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Floral Dissection

Aim: Study and discuss the given flowering plants and give its floral formula

Requirement: Flower, Forceps, Blade, Slides, Cover Slip, Microscope, Tape

LILIUM CANDIDUM

Kingdom: Plantae

Division: Anglospervae

Class: Monocot

Family: Liliaceae

Genus: lilium

Species: Candidum

Overay: Trilocular

Root: Advertitious Root

Stem: Herbaceous, erect

Tepals: 6 in number

Infloresnce: Racenose or umbel

Flower: Bracteate, bisoual, actionopic

Floral Formula

Br ⊕♀P3+3 A3 G(3)

floral dissection

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Study the pH and water holding capacity of different soil samples.

AIM: To study the pH and water holding capacity of different soil samples.

REQUIREMENTS: Soil samples, measuring cylinders, funnel, filter papers and pH indicator.

PROCEDURE:

Take 2 funnels and line them with filter paper

Put these funnels in a measuring cylinder

Put the 2 soil samples in  separate funnels

The weight of soil sample should be same in both (25g)

Pour equal amount of water in both funnels (25 ml)

Let the water drip in the cylinder

Not the volume of water collected

OBSERVATIONS:

The volume of water collected in cylinder of sample A was more than sample B

Also, the pH of sample A was higher

Calculations:

Volume of water retained by soil = Vol. of H2O poured-Vol. of H2O collected in cylinder

Water holding capacity = (Vol of H2O retained/Vol of H2O required) x 100

CONCLUSION:

Soil sample A is roadside soil and sample B is garden soil as sample B has more water holding capacity.

PRECAUTIONS:

The water should be poured slowly

The measuring cylinders should be properly calibrated.

Study and identify the transverse section of testes and ovary through permanent slides.

Aim: To study and identify the transverse section of testes and ovary through permanent slides.

Requirements: Permanent slides of transverse section of Testes and ovary, microscope

Observation:

T.S of Mammalian Testes

The mammalian testes are covered with a thick fibrous tissue called tunica albuginea

The testes consist of a many seminiferous tubules embedded in the interstitial tissues.

Various types of cells are present from outside towards the lunar in the following order:-

Spermatogonia(2n)———>Spermatocytes ( ) ———>Sepermatids———>Spermatozoa(n) i.e. sperms

Between the germinal cells, pyramidal shaped cells called Sertoli cells are present

A large number of sperms have their head embedded in the Sertoli cells.

The interstitial tissue has Leydig cells which produce testosterone.

T.S. of Mammalian Ovary

A mammalian ovary is a solid structure bounded germinal epithelium followed by a thick layer of fibrous tissue called tunica albuginea.

The ovary consists of the outer cortex and inner medulla.

The medulla consists many rounded or oval bodies called ovarian follicles at various stages of development.

The development of follicle is as follows:-

10 follicle——>20 follicle—–>30 follicle—->Graffian follicle—–>corpus luteum

The cortex contains round and mature follicles along with corpus luteum.

Precaution:

Handle the microscope with care

Use find adjustment for better focus

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Study Pollen Germination on a Slide

Aim:  To study pollen germination on a slide.

Apparatus and materials required: Fresh seasonal flower slides, microscope, beaker, cavity slide, boric acid, sucrose.

Procedure:

Prepare a nutrient solution by dissolving 10g sucrose and 10 mg boric acid in 100 ml water.

Take a few drops of this solution on a clear slide, dust a few pollen grains from the stamen of a mature flower in it.

Obverse the slide under the microscope after 5 minutes. Keep observing the slide regularly after intervals of half an hour.

Observations:

In a nutrient solution or nutrient-rich medium, the pollen grains germinate. The tube/vegetative cell enlarges and comes out the pollen grains through one of the germ pores to form a pollen tube. The generative cell nucleus soon passes into it and dives to make 2 sperm nuclei (male gametes). Each male gamete is lenticular to spherical in outline.

Precautions:

Flowers should be freshly picked

Use a clear cavity slide to observe pollen grain

 

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