Biology

How Do Organisms Reproduce?

Question:

(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.

Answer:

a) Role of placenta in the development of human embryo: A special tissue develops between the uterine wall and the embryo (foetus) called placenta, where exchange of nutrients, glucose and oxygen takes place. The developing embryo will also generate waste substances which can be removed by transferring them into the mother’s blood through the placenta. The development of the child inside the mother’s blood takes approximately nine months.
(b) Sexually transmitted diseases (STDs) transmitted by bacteria are:
(i) Gonorrhoea (ii) Syphilis
STDs transmitted by virus:
(i) AIDS (ii) Genital warts
The most effective contraceptive which prevents the spread of these diseases is by the use of mechanical barriers such as physical devices like condoms.

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How Do Organisms Reproduce?

Q 1.

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

Q 2.

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 3.

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

Q 4.

Name the largest cell present in the human body.

Q 5.

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

Q 6.

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

Q 7.

How does binary fission differ from multiple fission ?

Q 8.

What are the advantages of sexual reproduction over asexual reproduction?

Q 9.

List any four modes of asexual reproduction.

Q 10.

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

Q 11.

What is the importance of DNA copying in reproduction?

Q 12.

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 13.

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

Q 14.

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

Q 15.

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

Q 16.

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

Q 17.

State the method used for growing rose plants.

Q 18.

(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 19.

List and explain in brief three methods  of contraception.

Q 20.

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

Q 21.

Asexual reproduction takes place through budding in :
(a) Amoeba
(b) Yeast
(c) Plasmodium
(d) Leishmania.

Q 22.

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

Q 23.

Why is variation beneficial to the species but not necessarily for the individual?

Q 24.

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

Q 25.

Write the full form of DNA. Name the part of the cell where it is located. Explain its role in the process of reproduction of the cell.

Q 26.

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

Q 27.

List the parts of human male reproductive system which contribute fluid to the semen. State two advantages semen offers to the sperms.

Q 28.

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

Q 29.

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

Q 30.

If a woman is using a copper-T will it help in protecting her from sexually transmitted diseases?

Q 31.

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

Q 32.

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

Q 33.

Explain the following methods of contraception giving one example of each:
(i) Barrier method
(ii) Hormonal imbalance method
(iii) Surgical method.

Q 34.

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.

Q 35.

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 36.

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 37.

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

Q 38.

How is the process Of pollination different from fertilization ?

Q 39.

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

Q 40.

(a) In the human body what is the role of
(i) seminal vesicles, and (ii) prostate gland?
(b) List two functions performed by testis in human beings.

Q 41.

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

Q 42.

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

Q 43.

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

Q 44.

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 45.

How will an organism be benefited if it reproduces through spores?

Q 46.

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 47.

Why does menstruation occur?

Q 48.

What are the different methods of contraception?

Q 49.

(a) Name the parts labelled A, B, C, D and E.
how-do-organisms-reproducechapter-wise-important-questions-class-10-science-8
(b) Where do the following functions occur?
(i) Production of an egg
(ii) Fertilisation
(iii) Implantation of zygote.
(c) What happens to the lining of uterus:
(i) before release of a fertilised egg?
(ii) if no fertilisation occurs?

Q 50.

State what type of method is used for growing jasmine plant.