Lakhmir Singh Manjit Kaur Class 10 Biology Ch 3 ‘How Do Organisms Reproduce’ Inside Questions & Answers

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Inside Questions of Lakhmir Singh Manjit Kaur Class 10 Biology Chapter 3 ‘How Do Organisms Reproduce’.

Board CBSE
Class 10
Subject Biology
Chapter Name How Do Organisms Reproduce

(1) What is reproduction?

Ans. The production of new organisms from the existing organisms of the same species is known as reproduction.

(2) In how many methods reproduction can be divided?

Ans. Reproduction can be divided in two groups-

Asexual reproduction.

Sexual reproduction.

(3) What is Asexual reproduction? Give example.

Ans. The production of a new organism from a single parent without the involvement of sex cells is called asexual reproduction.

Ex. Binary fission in Amoeba, Budding in hydra, regeneration in Planaria.

(4) What is called Sexual reproduction? Give example.

Ans. The production of new organisms from two parents by making use of their sex cells is called sexual reproduction.

Example: Humans, Fish, Frogs etc.

(5) Write one difference between asexual and sexual reproduction.

Ans. In asexual reproduction only one parent is needed whereas In sexual reproduction two parent are needed.

(6) Write the methods by which asexual reproduction take place. Give one example of each.

Ans. asexual reproduction take place in sex different method –

(i) Fission – Amoeba.

(ii) Budding – Hydra.

(iii) spore formation – Bread mould plant.

(iv) Regeneration – Planaria.

(v) Fragmentation – Spirogyra

(vi) Vegetative propagation – Bryophyllum plant.

(7) What is Binary Fission?

Ans. In Binary fission the parent organism splits to form two new organisms.

(8) How does Amoeba reproduce?

Ans. When the amoeba cell has reached its maximum size of growth, then first the nucleus of Amoeba lengthens and divides into 2 parts. Afterthat the cytoplasm of Amoeba divides into two parts one part around each nucleus. In this way one parent Amoeba divides to form two smaller amoeba. And we say that one Amoeba produces two Amoebae.

(9) What is multiple fission?

Ans. In multiple fission the parent organism splits to form many new organisms at the same time.

(10) Name the mosquito which caries the parasite of Malaria disease called Plasmodium.

Ans. The female Anopheles mosquito.

(11) Define Budding.

Ans. In Budding a small part of the body of the parent organism grows out as a bud which then detaches and become new organism.

(12) How does Hydra reproduce?

Ans. Hydra first a small outgrowth called bud is formed on the side of its body by the repeated mitotic divisions of its cells. This bud then grows gradually to form a small Hydra by developing aq mouth and tentacles. And finally the tiny new hydra detaches itself from the body of  parent Hydra and lives as a separate organism.

In this way a parent Hydra produces a new Hydra.

(13) How does Yeast reproduce?

Ans. In Yeast first a bud appears on the outside of the cell wall. The nucleus of parent yeast cell than divides into two parts and one part of the nucleus moves into the. Ultimately the bud separates off from the parent yeast cell and forms a new yeast cell.

The budding in yeast however often takes place so fast that the first buds start forming their own buds and all of them remain attached to the parent yeast cell forming a chain of yeast cells. After some of time all the yeast cell of the chain separate from one another and form individual yeast plants,

(14) Define Spore Formation.

Ans. In spore formation the parent plant produces hundreds of microscopic units called spores. When the of the plant burst then the spores spread into air. When these air borne spores land on food under favourable conditions they germinate and produces new plants.

(15) Define Regeneration.

Ans. The process of getting back a full organism from its body parts is called regeneration.

(16) Define Fragmentation.

Ans. The breaking up of the body of a simple multicellular organism into two pieces on maturing each of which subsequently grows to form a complete new organism is called fragmentation .

(17) Give example which can reproduce by the method of fragmentation.

Ans. Spirogyra, Sea anemones.

(18) Write the reproduction process of spirogyra.

Ans. spirogyra is a green filamentous alga plant which is found in ponds, lakes and slow moving streams. Spirogyra filament simply breaks into two or more fragments on maturation and each fragment then grown into a new spirogyra,

(19) Write the difference between Fission and Fragmentation.


Fission Fragmentation
(i) In fission a unicellular organism breaks up to form two or more daughter organisms. (ii) In fragmentation, a multicellular organism organism breaks up to form two or more daughter organisms.

 (20) Define Vegetative Propagation.

Ans. In Vegetative propagation new plants are obtained from the parts of old plants without the help of any reproductive organs.

(20) Name one plants which can reproduced by vegetative propagation by using either a piece of its stem or its leaves.

Ans. Bryophyllum.

(21) Define Artificial Propagation of Plants.

Ans. The process of growing many plants from one plant by man by man made methods is called Artificial propagation of plants.

(22) Name three common methods for the artificial propagation of plants.

Ans. The three common methods for the artificial propagation of plants are-




(23) What is Cutting? Name the plants which are grown by means of cutting.

Ans. A small part of a plant which is removed by making a cut with a sharp knife is called cutting

Bougainvillea, Grapes, Sugarcane, bananas, cactus etc can be grown by means of cutting.

(24) Define layering. Give one example.

Ans. In this method a branch of a plant is pulled towards the ground and a part of it is covered with moist soil leaving a tip of the branch exposed above the ground. After some time new roots develop from the part of the branch buried in the soil. The branch is then cut off from the parent plant. The part of the branch which has developed roots grows to become new plant.

Ex. Jasmine plant.

(25) Define Grafting. Name some example.

Ans. Grafting is a method in which the cut stems of different plants are joined together in such a way that the two stems join and grow as a single plant.

Example: Apple, Peach, Apricot, Pear trees etc.

(26) What is Stock and Scion?

Ans. Stock is the lower part of a plant havi0ng the roots. Scion is the upper part of a plant which may have leaves on it.

(27) Write Some advantages of grafting method of Artificial Propagation.

Ans. (a) Grafting enables us to combine the most desirable characteristics of the two plants in its flowers and fruits.

(b) By grafting method a very young scion can be made to flower and produce fruits quite fast when it is grafted to the stock of a mature plant.

(c) grafting can be used to produce varieties of seedless fruits.

(28) Write the advantages of Artificial Vegetative Propagation.

Ans. (i) The new plants produced by artificial vegetative propagation will be exactly like the parent plants. Any desirable features of the parent plant will be replicated in the new plants.

(ii) The plants grown by this method usually need less attention in their early years than the plants grown from seeds.

(iii) Many plants can be grown from just one parent plant by artificial propagation.

(29) Define Tissue culture.

Ans. The production of new plants from a small piece of plant tissue removed from growing tips of a plant in a suitable growth medium is called tissue culture.

(30 Define Micro propagation.

Ans. The tissue culture technique is being used increasingly for the production of ornamental plants like Orchids, Dahlia, Carnation etc. The production of plants by the method of tissue culture is known as micro propagation.

(31) Write some advantages of tissue culture.

Ans. (i) Tissue culture is very fast technique. Thousands of plantlets can be produced in few weeks time from a small amount of plant tissue.

(ii) The new plants produced by tissue culture are disease free.

(iii) Tissue culture can grow plants round the year, irrespective of weather or season.

(32) What is clones?

Ans. The new organisms produced by one parent through asexual reproduction are called clones.

(33) Write the importance of variations in organisms.

Ans. The importance of variations in organisms introduced during reproduction is that it helps the species of various organisms to survive and flourish even in adverse environment.

(34) What is sex cells?

Ans. Sexual reproduction takes place by the combination  of special reproductive cells called sex cells.

(35) Define Gametes.

Ans. Celled involved in sexual reproduction called gametes.

(36) How sexual reproduction in plants take place?

Ans. The sexual reproduction in plants takes place in the following steps-

Ans. The male organ of flower called stamen makes the male gametes of the plant. These male gametes are present in pollen grains.

The female organ of a flower called carpel makes the female gametes of the plant. These female gametes are present in ovules. The female gametes present in ovules are also called ova, egg cells or just eggs.

The male gametes present in pollen grains fertilise the female gametes or egg cells present in ovules.

The fertilized egg cells grow within ovules and become seeds.

The seeds produced new plants on germination.

(37) Write the main parts of a flower? Describe them.

Ans. The main parts of a flower are: –

Receptacle, sepals, Petals, Stamen and Carpel.

Receptacle:- The base of a flower to which all the parts of a flower are attached is called receptacle.

Sepals:- The green leaf like parts in the outermost circle of a flower are called sepals.

Petals:- The colorful parts of a flower are called Petals.

Stamen:- The little stalks with swollen tops just inside the ring of petals in a flower are called stamen.

Carpel:- In the centre of a flower there is a flask shaped organ called carpel.

(38) Write the names of female organ of a plant.

Ans. The two names of female organ of plant are Carpel and Pistil.

(39) Define Unisexual flowers.

Ans. The flowers which contain only one sex organ either stamen or carpel are called unisexual flowers.

Example: Flower of Papaya and Watermelon.

(40) Define bisexual flowers.

Ans. The flowers which contain both the sex organs stamens as well as carpel are called bisexual flower.

Example: Hibiscus, Mustard plants.

(41) What is Pollination?

Ans. The transfer of pollen grains from the anther of a stamen to the stigma of a carpel is called pollination.

(42) Write the difference between self pollination and cross pollination.

Ans. When the pollen grains from the anther of a flower are transferred to the stigma of the same flower called self pollination Whereas, When the pollen grains from the anther of a flower on one plant are transferred to the stigma of a flower on another similar plant it is called cross pollination.

(43) How fertilization takes place in flowers? Write in details.

Ans. When a pollen grain falls on the stigma of the carpel, it bursts open and grows a pollen tube downwards through the style towards the female gamete in the ovary. A male gamete moves down the pollen tube. The pollen tube enters the ovule in the ovary . The tip of pollen tube bursts open and male gametes comes out of pollen tube. In ovary the male gametes of pollen combines with the nucleus of female gamete or egg present in ovule to form a fertilized egg.

And then we can fertilization takes place.

(44) Name the flower parts which develop and becomes a fruit.

Ans. Ovary.

(45) What is cotyledon?

Ans. The part of seeds which contains stored food for the baby plant called cotyledon.

(46) What is called germination of seeds?

Ans. The beginning of the growth of seeds is called germination of seeds.

(47) Write the terms which are involved in sexual reproduction.

Ans. The terms which are involved in sexual reproduction are-

Male sex, Female sex, Gametes, Sperms, Ova, Fertilisation, Zygote and Embryo.

(48) Define the terms Sperms, Ova.

Ans. an animal having male sex cells called sperms in its body is called male.

An animal having female sex cells called Ova in its body is called female.

(49) Write the difference between Human sperm and Human ovum.


Human sperm Human ovum
A human sperm (male gamete). A sperm is about 0.05 mm long. A sperm has a head, a middle piece and a tail. A sperm is a single cell with nucleus, cytoplasm and cell membrane. A human ovum or egg (female gamete). An ovum or egg is round and about 0.15 mm in diameter. The ovum or egg is also a single cell having a nucleus, cytoplasm and cell membrane.

(50) What is called Zygote?

Ans. Fusion of gametes gives rise to a single cell called zygote.

(51) What is called Internal fertilization?

Ans. The fertilization which occurs inside the female body is called internal fertilization.

Internal fertilization takes place in mammals, birds and reptiles.

(52) What is called external fertilization?

Ans. The fertilization which occurs outside the female body is called external fertilization.

Example: In Amphibians and fishes, external fertilization takes place.

(53) Write one advantages of sexual reproduction over asexual reproduction.

Ans. In sexual reproduction the offsprings, although similar to their parents, are not identical to them or to one another. This because the offsprings receive some genes from the mother anod some from his father. Whoever, in asexual reproduction the offsprings are almost identical to their parent because they have the same genes as their parent. So much genetic variation is not possible in asexual reproduction.

(54) How Sexual reproduction in Animals takes place?

Ans. The sexual reproduction in animals takes place in the following points –

(i) The male parents produces male gametes called called sperms. The sperm has a long tail for movement.

(ii) The female parent produces female gametes called ova. The ovum is a much bigger cell than the sperm having a lot of cytoplasm.

(iii) The sperm enters into the ovum and fuses with it to form a new cell called zygote. This process is called fertilization. So the zygote is a fertilized ovum.

(iv) The zygote then devides again and again to form a large number of cells and ultimately zygote grows and develops to become a new baby.

(55) Define puberty.

Ans. The age at which the sex hormones begin to be produced and the boy and girl become sexually mature is called puberty.

(56) At which age girls and boys basically attain puberty.

Ans. Girls – 10/12 years.

Boys – 13/14 years.

(57) What is testosterone?

Ans. The testes produce the male sex hormones called testosterone.

(58) What is oestrogen and progesterone?

Ans. Ovaries produce two female sex hormones namely oestrogen and progesterone.

(59) Point out the various changes which occur in boys at puberty.

Ans. (i) Hair grows under armpits, genital area between the thighs and also other parts of the body like chest, face.

(ii) Body becomes more muscular due to the development of muscles.

(iii) The voice cracks.

(iv) Chest and shoulders broadened

(v) Penes and testes become larger.

(vi) Testes start to produce sparms.

(60)  Write the changes which occur in girls at puberty.

Ans. (i) Hair grows under armpits, genital area between the thighs.

(ii) Breast develop and enlarge.

(iii) The hips broaden.

(iv) Extra fat is deposited in the various of the body like hips and thighs.

(v) Ovaries start to release eggs.

(vi) Monthly period is start.

(61) Name the organs by which human male reproductive system consist.

Ans. Testes, Scrotum, Epididymis, Seminal vesicles, Prostrate gland, penis.

(62) Name the organs of human female reproductive system.

Ans. Ovaries, Oviducts, Uterus, Vagina.

(63) In where the fertilization of the ovum takes place.

Ans. The fertilization in the ovum takes place in the oviduct.

(64) Define implantation.

Ans. The embedding of embryo in the thick lining of the uterus is called implantation.

(65) Define the term gestation.

Ans. The time period from the fertilization up to the birth of the baby is called gestation.

(66) What is the average gestation period in humans.

Ans. About 9 month.

(67) Write one difference between Zygote, Embryo and Foetus.


Zygote Embryo Foetus
(i) Zygote is formed by the fusion of male and female gametes. (ii) Embryo is formed by the repeated cell division of a zygote (iii) Foetus is formed by the growth and development of an embryo.

(68) What is menopause?

Ans. The permanent stoppage of Mensuration in a women called menopause.

(69) At what age Menopause occurs in women?

Ans. 45 – 50 years.

(70) What is called contraception?

Ans. The prevention of pregnancy in women is called  contraception.

(71) In how many categories birth control method can be devided? Name them.

Ans. The birth control method can be divided into 3 categories-

(i) Barrier method

(ii) Chemical method

(iii) Surgical method

(72) Write an important benefit in the use of condom.

Ans. It protects a person from the sexually transmitted diseases such as gonorrhea, AIDS etc.

(73) Write chemical method of preventing pregnancy.

Ans. In the chemical method of preventing pregnancy the female use two types of pills which are made of specific drugs Namely, oral pills and vaginal pills.

(74) What is female foeticide.

Ans. Killing of the unborn girl child is called female foeticide.

(75) Define Sexually transmitted disease.

Ans. The disease which are spread by sexually contact with an infected person are called sexually transmitted disease.

(76) Write the name of some common sexually transmitted disease.

Ans. Gonorrhoea, Syphilis, AIDS etc.

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