NCERT Class 10 Chapter 8 Organisms Reproduction CBSE Board Sample Problems Long Answer

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Question

Write the functions of placenta.

Solution

The placenta serves primarily as an organ that permits the inter change of materials carried in the blood of mother and Foetus. The main functions are: Nutrition:

  • Supply of nutrient materials to Foetus.

  • Respiration: Supply of to Foetus and receive back from it.

  • Excretion: Fluid nitrogenous waste products escape through the placenta.

  • Barrier: The placenta is barrier like semi permeable membrane.

  • Storage: The placenta stores fat, glycogen and iron for the embryo before the formation of liver.

  • Hormonal function: The placenta secures extra ovarian hormones estrogen and progesterone in female during pregnancy that serves to maintain Foetus.

Question

Give reasons:

1. Placenta ¡s extremely essential for foetal development.

2. Blocking of vas-deferens prevents pregnancy.

3. Wind acts as a pollinating agent.

4. Use of condoms prevents pregnancy.

5. Blocking of Fallopian tubes prevents pregnancy.

Solution

  • Placenta is a temporary organ which is extremely essential for foetal development because it helps in nutrition, respiration, excretion, etc., of the Foetus through the maternal supply. Baby connects with placenta via umblical cord.

  • Blocking of vas deferens is known as vasectomy which prevents passage of sperms, hence preventing pregnancy.

  • Anemophily or wind pollination is a form of pollination where, wind acts as a pollinating agent because it helps in transfer of pollen grains from anther to stigma of a flower. e.g. wheat, rice, corn.

  • Condoms as physical barrier, which prevent entry of sperms in to vagina, hence prevents pregnancy.

  • If Fallopian tube is blocked surgically, which is better known by the name Tubectomy, sperm and egg do not meet and fertilization does not take place.

Question

Draw the diagram of a flower and label the four whorls. Write the names of gamete producing organs in the flower.

Solution

Male gamete forming organ - Anther/ Stamen

Female gamete forming organ- Pistil/Ovary/ Ovule

A flower and label the four whorls

A Flower and Label the Four Whorls

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Question

(a) Explain regeneration in Planaria.

(b) Why cannot multicellular complex organism show power of regeneration?

Solution

(a) Regeneration:

  • The process of getting back full organism from its body part is called regeneration. For example simple animals like Hydra and Planaria show regeneration.

  • Planaria (Flatworm) is found in freshwater ponds. If the body of planaria somehow gets cut into number of pieces then each body piece can regenerate into complete planaria.

Regeneration in Planaria

Regeneration in Planaria

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  • It occurs by the process of growth and development. The cells of cut body part divide rapidly to make ball of cells. The cells present in ball of cells move to their proper places and form various organs and body parts of an organisms.

  • In multicellular complex organisms, specialized cells make up tissue, tissue makes up organ, organ makes up organ system and finally organ system makes up organism. They have a high degree of organization in their body so they cannot reproduce their body through regeneration.

Question

a. Draw a well labelled diagram to show the process of fertilization in flower.

b. Name the common secondary sexual characteristics in males and females.

Solution

a.

The process of fertilization in flower

The Process of Fertilization in Flower

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B

i. Pubic hair and armpit hair

ii. Development

Question

(i) Draw a neat diagram of female reproductive system and label the following:

(a) Part where eggs are formed.

(b) Site of fertilization.

(c) Place of implantation.

(d) Place for entry of sperms.

(ii) What happens in case an egg fails to fertilize?

iii) Give one method to prevent both STD and unwanted pregnancy.

Solution

a. Ovary

b. Oviduct

c. Uterus

d. Vagina

Female Reproductive System

Female Reproductive System

Female Reproductive System

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(ii) Menstruation

(iii) Use of condoms

Question

Mrs. Seghal’s family was very happy after the birth of their second child. Her friend, Mrs. Raman suggested her to undergo Tubectomy.

a) What is Tubectomy?

b) Why do you think Mrs. Raman gave her such a suggestion?

c) Can Tubectomy prevent spread of sexually transmitted diseases?

d) Give reason for your answer. Why is there a need of adopting contraceptive methods?

Solution

  • Tubectomy is method of contraception in which the fallopian tube is cut and tied

  • Tubectomy is method of contraception hence prevents pregnancy

  • No, can’t prevent entry of semen

  • To control population? To prevent unwanted pregnancies? To prevent transmission of sexually transmitted diseases. (Any two)(1 +1)