Biology

How Do Organisms Reproduce?

Question:

Describe in brief the role of (i) testis (ii) seminal vesicle, (iii) vas deferens, (iv) ureter and (v) prostate gland in human male reproductive system.

Answer:

  • Testis: Testes are oval shaped primary reproductive organs in men. The function of testes is to produce sperms and male sex hormone testosterone. The scrotum provides optimal temperature for the formation of sperms.
  •  Seminal vesicle: Seminal vesicles are a pair of thin walled muscular elongated sac which secrete fluid for nourishment of sperms.
  • vas deferens: The sperms are carried by a long tube called vas deferens to organs called seminal vesicles where the sperms get nourishment and stored.
  • Ureter It is the tube that carries urine from kidney to the urinary bladder. In humans, there are two ureters, one attached to each kidney.
  •  Prostate glands: Prostate glands produce a fluid which is released in the urethra along with secretion of seminal vesicles for nourishment and transportation of sperms.
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How Do Organisms Reproduce?

Q 1.

What is the effect of DNA copying which is not perfectly accurate on the reproduction process?

Q 2.

How are the modes for reproduction different in unicellular and multicellular organisms ?

Q 3.

The anther contains :
(a) Sepals
(b) Ovules
(c) Carpel
(d) Pollen grains.

Q 4.

What is meant by asexual reproduction? List its any two different forms.

Q 5.

Name the largest cell present in the human body.

Q 6.

Why does menstruation occur?

Q 7.

Expand AIDS. List any four methods of prevention (control) of AIDS.

Q 8.

List any four modes of asexual reproduction.

Q 9.

Define the term puberty. List two  changes observed in girls at the time of puberty.

Q 10.

State one genetically different feature between sperms and eggs of humans. What is its consequence?

Q 11.

“DNA copies generated during  reproduction will be similar but may not be identical to the original.” Justify this statement.

Q 12.

What is the role of the seminal vesicles and the prostate gland ?

Q 13.

Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

Q 14.

a) List any four reasons for adopting contraceptive methods.
(b) If a woman is using Copper-T, will it help in protecting her from sexually transmitted diseases? Why?  

Q 15.

Define the terms unisexual and bisexual giving one example of each.

Q 16.

What is ‘reproduction’? Mention the importance of DNA copying inreproduction.

Q 17.

State the method used for growing rose plants.

Q 18.

Why is DNA copying an essential part of the process of reproduction?

Q 19.

What is AIDS? Which microbe is responsible for AIDS infection? State one mode of transmission of this disease. Explain in brief one measure for the prevention of AIDS.

Q 20.

Why is vegetative propagation practised for growing some type of plants?

Q 21.

Which of the following is not a pan Of the female reproductive system in human beings ?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube

Q 22.

(a) Draw a diagram showing germination of pollen on stigma of a flower.
(b) Label pollen grain, male germ- cells, pollen tube and female germ-cell in the above diagram.
(c) How is zygote formed?

Q 23.

List any four reasons for vegetative propagation being practised in the growth of some type of plants.

Q 24.

How does growing embryo get nutrition from the mother’s blood?

Q 25.

List two advantages of practising vegetative propagation in plants. Select two plants raised by this method from the list given below:
Banana, Gram, Pea, Rose, Tomato, Wheat.

Q 26.

What is the importance of DNA copying in reproduction?

Q 27.

What is regeneration? State a reason why a more complex organism cannot give rise to new individuals through this method.

Q 28.

With the help of suitable diagrams, explain the various steps of budding in Hydra.

Q 29.

State in brief the changes that take place in a fertilised egg (zygote) till birth of the child in the human female reproductive system. What happens to the egg when it is not fertilised?

Q 30.

What are the changes seen in girls at the time Of puberty ?

Q 31.

Draw a diagram of a human female reproductive system and label the part
(i) that produces egg
(ii) where fusion of egg and sperm take place
(iii) where zygote is implanted
What happens to human egg when it is not fertilised?

Q 32.

How does binary fission differ from multiple fission ?

Q 33.

What are the functions performed by the testes in human beings?

Q 34.

What are sexually transmitted diseases?
Name four such diseases. Which one of them damages the immune system of human body?

Q 35.

What are the advantages of sexual reproduction over asexual reproduction?

Q 36.

Differentiate between ‘self-pollination’ and ‘cross-pollination’. Describe double fertilisation in plants.

Q 37.

Name one sexually transmitted disease each caused due to bacterial infection and viral infection. How can these be prevented?

Q 38.

Mention the mode of reproduction used by
(a) Amoeba (b) Planaria.

Q 39.

What is reproduction? What are its two types? Which one of the two confers new characteristics on the offsprings and how?

Q 40.

Explain vegetative propagation with the help of two examples. List two advantages of vegetative propagation.

Q 41.

(a) Explain the role of placenta in the development of human embryo.
(b) Give example of two bacterial and two viral sexually transmitted diseases. Name the most effective contraceptive which prevents spread of such diseases.

Q 42.

List two advantages of vegetative  reproduction practised in case of an orange plant.

Q 43.

Name an organism which reproduces by spore formation. List three conditions favourable for spores to germinate and grow.

Q 44.

Name the two types of germ-cells present in human beings. How do they structurally differ from each other? Give two differences.

Q 45.

List and explain in brief three methods  of contraception.

Q 46.

Why is DNA copying an essential part of the process of reproduction?

Q 47.

How does the embryo get nourishment inside the Mother’s body?

Q 48.

How does reproduction help in providing stability to populations Of species?

Q 49.

What could be the reasons for adopting contraceptive methods?

Q 50.

“Variations that confer an advantage to an individual organism only will survive in a population.” Justify.