Very Short answer -Class 10 -Science- Biology-Chapter 7: How Do Organisms Reproduce

Class 10 -Science- Very Short answer  -Biology-Chapter 7: How Do Organisms Reproduce

Q1.Differentiate between pollen grain and ovule. 

Q2 Give reasons as to why the following processes are different from each other:

a. Fission in Amoeba and Plasmodium .

b. Binary fission and Fragmentation.

Ans : a. In Amoeba during binary fission the cell divides into two daughter cells while in Plasmodium multiple fission occurs, where the cell divides into many daughter cells.

b. In binary fission, a cell divides into two daughter cells while in fragmentation, the body of a multicellular organisms divides into two or more parts which grow further.

Q3. Differentiate between germination and fertilization,

Q4. List two functions performed by testis in human beings

Ans :

Spermatogenesis: The testes produce sperm cells (spermatozoa) through a process called spermatogenesis. This process occurs within the seminiferous tubules of the testes and involves the differentiation of spermatogonia into mature sperm cells.

Production of testosterone: The testes secrete the male sex hormone testosterone. Testosterone plays a crucial role in the development and maintenance of male reproductive tissues and secondary sexual characteristics, such as facial hair growth, deepening of the voice, and muscle mass development.

Q6. What is the main difference between sperms and eggs of human? Write the importance of this difference?

Ans : Sperms are motile and are produced in . large numbers by a male. Egg are non-motile and only one is produced at a time by the female. Sperms are motile as they have to travel up to egg for fertilization. It becomes zygote, remains protected inside female’s body and gives rise to foetus and baby.

Q7. Define the following processes of asexual reproduction:

a. Spore formation

b. Regeneration

c. Multiple fission

Ans:

a.Sporeformation: Production of specialized reproductive cells for dispersal and asexual reproduction.

b. Regeneration: Ability to replace lost or damaged body parts, forming new individuals.

c. Multiple fission: Single organism divides into multiple genetically identical daughter organisms.

Q8. The chromosomal number of the sexually producing parents and their offspring is the same.” Justify this statement.

Ans:

 a. DNA copying is essential for formation of addition cellular apparatus, so that when DNA copies separate, each cell gets its own cellular apparatus.

b. The process of DNA copying results in variation each time. As a result, the DNA copies generated will be similar, but may not be identical to the original.

 Q9. Give two differences between a male and a female gamete.

Male gametes (sperm cells) are typically smaller and more streamlined, facilitating their movement to reach and fertilize the female gamete.

Male gametes are usually motile, equipped with flagella or other structures to enable movement towards the female gamete.

Female gametes (egg cells or ova) are larger and contain more cytoplasm to provide nourishment to the developing embryo after fertilization.

Female gametes are generally non-motile and remain stationary within the reproductive structures until fertilization occurs.

Q10. What kind of contraceptive methods prevents STDs and how?

Ans :  Barrier method prevent STDs. By this method there is no direct contact of genital organs of male and female and thus it prevents transmission of any infection.

Q11.a. List any two methods of asexual reproduction.

b. Explain how Spirogyra reproduces.

Ans: a. (i) Budding in Hydra and Yeast.

(ii) Spore formation in Fungi.

b. Spirogyra breaks up into smaller pieces upon maturation. These fragments grow into new individuals

Q12. How can pregnancy be prevented surgically?

Ans : Pregnancy can be prevented surgically by adopting:

 a. Vasectomy: When vas deferens in males are blocked surgically, sperm transfer will be prevented.

b. Tubectomy: When fallopian tubes are blocked, eggs will not be able to reach the uterus.

Q13. Mention any four ways of asexual reproduction.

Ans : Binary fission: Division of a single organism into two daughter organisms of equal size.

Budding: Formation of a new individual from an outgrowth or bud on the parent organism.

Fragmentation: Breaking of the parent organism into fragments, each of which can grow into a new individual.

Vegetative propagation: Production of new individuals from specialized plant structures such as runners, rhizomes, bulbs, or tubers without the involvement of seeds.

Q14. Mention the functions of (a) placenta (b) fallopian tube in the human female , reproductive system.

 Ans :  a. Placenta:

(

Q15. How can pregnancy be i) Helps in transporting glucose and oxygen from the mother to the embryo. (ii)  Waste generated by the embryo is removed by transferring it to the mother’s blood.

b. Fallopian tube: (i) Helps in carrying the egg from the ovary to the uterus.

 (ii) Fertilization occurs here.prevented surgically?

Ans : Pregnancy can be prevented surgically by adopting:

a. Vasectomy: When vas deferens in males are blocked surgically, sperm transfer will be prevented.

b. Tubectomy: When fallopian tubes are blocked, eggs will not be able to reach the uterus.