MP Board Class 10th Science imp questions Chapter 8 How do Organisms Reproduce?

CHAPTER        8

How do Organisms Reproduce ?

 

Objective Questions

 

Multiple Choice Questions

 

1. The anther contains

 

(a) sepals

 

(b) ovules

 

(c) pistil

 

(d) pollen grains.

 

2. Asexual reproduction takes place through budding in

(a) amoeba

 

(b) yeast

 

(c) plasmodium

 

(d) leishmania.

 

 

3. Which of the following is not a part of the female reproductive system in human?

(a) Ovary

 

(b) Uterus

 

(c) Vas deferens

 

(d) Fallopian tube.

 

4. Plants that have lost their capacity to produce seeds, reproduce by

(a) spores

 

(b) fission

 

(c) vegetative propagation

 

(d) regeneration

 

5. Where does fertilization take place in human beings?

(a) Uterus

 

(b) Cervix

 

(c) Vagina

 

(d) Fallopian tube.

 

6. The common passage for sperms and urine in the male reproductive system is

 

(a) urethra

 

(b) Ureter

 

(c) Vas deferens

 

(d) Seminal vesicle.

 

7. Which part of the flower ripens to form a fruit ?

(a) Ovule

 

(b) Carpel

 

(c) Ovary

 

(d) Egg cell.

 

Ans. 1. (d), 2. (b), 3. (c), 4. (c), 5. (d), 6. (a), 7. (c).

 

 

Fill in the Blanks

 

1. Hydra reproduces by………..

 

2. The full form of DNA is………..

 

3. In vegetative propagation, plants produced

………………are similar to parents.

 

4. The fertilized egg gets implanted in the lining of the ….………………

 

5…………………leads to the creation of new individuals in unicellular organisms.

 

Ans. 1. Budding, 2. Deoxyribo Nucleic Acid, 3. Genetically, 4. Uterus, S. Fission.

 

True/False

 

1. Cells use chemical reactions to build copies of their DNA.

 

2. Stamens and pistil are the reproductive parts of a flower.

 

3. Amoeba reproduces sexually.

 

4. If the fallopian tube in the female is blocked, the egg will be able to reach the uterus.

 

5. The embryo gets nutrition from the mother’s blood with the helps of a special tissue called placenta.

 

Ans. 1. True, 2. True, 3. False, 4. False, 5. True.

 

Match the Columns

 

Column ‘A’.                                Column ‘B’

 

1. Bisexual. (a) Ovum

 

2. Male (b) Hibiscus

 

3. Female. (c) Sperm

 

4. Unisexual. (d) Planaria

 

5. Regeneration (e) Human being

 

Ans. 1. → (b), 2. → (c), 3. (a), 4. (e), 5.-> (d).

 

Answer in one Word/Sentence

 

1. Is fertilization possible without pollination?

Ans. No, fertilization is followed by pollination.

 

2. What is the role of prostate gland?

Ans. It adds alkaline secretion into the semen which is essential for sperm activity.

 

3. Which part of the flower develops into a seed and a fruit ?

Ans. Ovule develops into a seed, while ovary ripens to form a fruit.

 

4. Which structures need to be blocked in males and females respectively to prevent pregnancy?

Ans. Vas deferens in males (Vasectomy), fallopian tube in females (Tubectomy).

 

5. Give an example of an organism which reproduces by fragmentation.

Ans. Spirogyra.

 

6. Out of the following plants which two plants are reproduced by vegetative propagation ?

Jasmine, Wheat, Mustard, Banana.

Ans. Jasmine, Banana.

 

Very Short Answer Type Questions

 

1. 1. How does binary fission differ from multiple fission?

Ans. In binary fission, a single cell divides into two equal halves. Amoeba and bacteria divide by binary fission.

In multiple fission, a single cell divides into many daughter cells simultaneously eg Plasmodium.

 

2. 2. Name the various types of asexual reproduction.

Ans. Various types of asexual reproduction are Fission, Budding, Spore formation, Fragmentation, Regeneration, Tissue culture.

 

3. 3. If a woman is using Copper-T, will it help in protecting her from sexually transmitted diseases?

Ans. No, Copper-T will not protect the woman from sexually transmitted diseases. It is a method of birth control in which sperms are killed but it does not kill STD causing microbes.

 

4. 4. Write the names of two contraceptive devices.

Ans. Condoms, contraceptive pills and copper-T etc.

 

5. 5. Define grafting.

Ans. In grafting, one part of plant is inserted into another plant in a way that both of them will unite and grow together as a single plant.

 

6. 6. What is pollination?

Ans. “The process by which plant pollen is transferred from the male reproductive organs to the female reproductive organs to form seeds, is called pollination.”

 

7. 7. What is cross pollination or allogamy?

Ans. It is the process of transfer of pollen grains from the anther of a flower to stigma of another flower, of same or different plant, of the same or closely-related species. Q. 8. What happens if fallopian tube is blocked? Ans. If fallopian tube is blocked, the egg will not be able to reach the uterus. In such case, fertilization will not take place.

 

9. 9. Why are testes in male located outside the abdominal cavity?

Ans. The formation of germ cells or sperms takes place in the testes. These are located outside the abdominal cavity in scrotum because sperm formation requires a lower temperature than the normal body temperature.

 

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

Ans. The secretions from seminal vesicles and prostate glands lubricate the sperms and provide a fluid medium for easy transport of sperms. Their secretion also provides nutrients in the form of fructose, calcium and some enzymes.

 

11. 11. What are the functions performed by the testis in human being?

Ans. Function of testis in human being-The formation of germ cells or sperms takes place in testes. Beside this they also secrete testosterone hormone, which regulate the formation of sperms, testosterone brings about changes in appearance seen in body at the time of puberty.

 

Short Answer Typ Questions

 

1. 1. What is the importance of DNA copying in reproduction ?

Ans. DNA is the genetic material present in the cells of all organisms. The genetic information from generation to generation is carried by DNA. It is therefore possible for the organism to produce organism of its own type due to DNA copying only. For the inheritance of traits of the parent, DNA copying is a must. DNA copying also brings about variation,

which forms the basis for the origin of new species.

 

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

Ans. Variations are beneficial to the species than the individual, because sometimes, for a species, the environmental conditions change so drastically that their survival becomes difficult. e.g. if temperature of water increases suddenly, then most of the bacteria living in water would die. Only a few variants that are resistant to heat would be able to survive. If these variants were not there, then the entire species of bacteria would have been destroyed. Thus, these variants help in the survival of species. However, all variations are not beneficial for the individual organisms.

 

3. 3. Reproduction is one of the most important characteristics of living beings.” Give three reasons in support of the statement.

Ans. Reproduction is an important characteristic of living beings because

 

(i) It is through reproduction that organisms create new individuals that look very much like themselves.

 

(ii) A species will be lost if it will not reproduce. Genital inheritance occurs due to reproduction. Reproduction is linked to the stability of population of species.

 

(iii) There is some variation in the newly-formed species during reproduction. The in-built tendency for variation during reproduction is the basis for evolution.

 

Q.4. What is vegetative propagation ? State two advantages and two disadvantages of this method

Ans. The method of reproduction in which a new plant is grown from a plant part such as root, stem or leaves is called vegetative propagation; Eg. rose, sugarcane etc.

 

Advantages

 

(1) Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds.

 

(2) All plants produced are genetically similar to the parent plant and have all its characteristics.

 

(3) It makes possible the propagation of plants that have lost the capacity to produce seeds like, banana, orange, rose and jasmine.

 

Disadvantages

 

(1) There is no genetic variation in plants.

 

(2) Plants are prone to diseases that are specific to the species.

 

5. 5. How is the process of pollination different from fertilization ?

Ans. Pollination is the process of transfer of pollens from anther to stigma of the same

or different flower(s). It occurs with the help of certain pollinators such as air, water, birds or insects.

Fertilization is the fusion or male and female gametes. It occurs inside the ovule and leads to the formation of zygote.

 

6. 6. Draw a labelled diagram of the longitudinal section of a flower. (2019, 21)

Ans.

-Q. 7. How does reproduction help in species?

Or

providing stability to populations of

Why is reproduction essential?

Ans. Living organism reproduce for a continuation of the generation of particular species. It helps in providing stability to the population of species by producing a new individual that resembles the parents. This is the reason why cats give birth to only cats or dogs give birth to only dogs. Therefore, reproduction provides stability to populations of dogs or cats or any other species.

 

8. 8. Define self pollination.

Ans. The self pollination : “When the pollination occurs in this pollination is called self pollination i.e., if the pollen grains from the anther of same flower then one flower transfer to the stigma of the same flower then this process is called self pollination.”

 

9. How does embryo get nourishment inside the mother’s body?

Ans. The embryo gets nourishment inside the mother’s body from the blood of mother. For this purpose a specific tissue known as placenta is developed which provide glucose, oxygen and other material required to the embryo from the mother’s body.

 

10. 10. Why is vegetative propagation practised for growing some types of plants?

Ans. Some plants have the capacity to reproduce new ones from their vegetative parts such roots, stem or leaves asexually. In this process, the new plants are produced easily and early. By this process, such plants can reproduce new plants which do not have capacity of producing seeds. The plants which are reproduced by this process are identical to their parents plants in all respect. This process is called vegetative propagation. Therefore, the vegetative propagation is practised for growing some types of plants.

 

Long Answer Type/ Analytical Questions

 

1. 1. Define reproduction. How does it help in providing stability to the population of species? Ans. Reproduction is the biological process of the production of new individual organisms or offsprings from their parents. The reproduction may be asexual or sexual in plants and sexual in human beings. In the absence of reproduction one particular species will disappear with time. Reproduction is the process of producing new individuals of the same species by existing organisms of a species by giving birth to new individuals as the rate of birth must be at par with the rate of death to provide stability to a population of species.

 

2. 2. Explain the term regeneration as used in relation to reproduction of organisms. Describe briefly how regeneration is carried out in multicellular organisms like Hydra.

Ans. The process of growing an entire organism from a single cell or group of cells is called regeneration. Many organisms give rise to a new individual organism from their body parts. That is, if the individual is somehow cut or broken into many pieces, many of these pieces grow into separate individuals. For example, simple animals like Hydra and Planaria can be cut into any number of pieces and each piece grows into a complete organism. This is known as regeneration. Regeneration is carried out by specialised cells. These cells proliferate and make large number of cells.

Organisms such as Hydra use regenerative cells for reproduction in the process of budding. In Hydra a bud develops as an outgrowth due to repeated cell division at one specific site. Those buds develop into tiny individuals, and when fully mature, detach from the parent body and become new independent individuals.

 

3. 3. List three techniques that have been developed to prevent pregnancy. Which one of these techniques is not meant for males? How does the use of these techniques have a direct impact on the health and prosperity of a family? Ans. The three techniques developed to prevent pregnancy are use of condoms, oral contraceptive pills and placement of contraceptive devices such as Copper-T in the uterus. Among the above techniques, use of oral contraceptive pills which are drugs that change the hormonal balance so that eggs are not released and placement of contraceptive devices, such as copper-T in the uterus are not meant for males.

Use of the techniques to prevent pregnancy will help in family planning. This will be helpful in enhancing the prosperity of the family. Birth of a child demands care, responsibility, and it affects the family economically also. If there will be less income and more mouths to feed, there will be economic burden on the family. Apart from it, pregnancy makes a major impact on the body and mind of the woman. If she is not ready for it, her health will be adversely affected.

 

4. 4. (a) Name the human male reproduction organ that forms sperms and also secretes a hormone. Write the functions of the secreted hormone.

 

(b) Name the parts of human female reproductive system where

 

(i) fertilization takes place.

 

(ii) implantation of the fertilized egg occurs.

 

Explain how the embryo gets nourishment inside the mother’s body.

 

Ans. (a) The formation of sperms in males takes place in the testes which also secretes a hormone called testosterone.

 

Functions of testosterone-(i) Regulates the formation of sperms in the testes.

(ii) Brings about changes in the appearance seen in boys at the time of puberty. It is responsible for secondary sexual characteristics in males.

 

(b) (i) Fertilisation in females takes place in the oviduct or fallopian tube.

(ii) The implantation of the fertilised egg occurs in the lining of the uterus, where it continues to grow and develop organs to become foetus.

 

After fertilisation, the lining of the uterus thickens and is richly supplied with blood to nourish the growing embryo. The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. It is a disc embedded in the uterine wall. Placenta contains villi on the embryo’s side of the tissue and blood spaces on mother’s side surrounding the villi. This provides a large surface area for glucose and oxygen to pass from the mother to the embryo. The waste substances generated by embryo are removed by transferring into mother’s blood through placenta.

 

5. 5. List six specific characteristics of sexual reproduction.

Ans. Specific characteristics of sexual reproduction are as follows

(1) In sexual reproduction, both male and female parents are involved.

(2) Fully developed reproductive parts are present in it. eg, secondary sexual haracteristics appear in humans at puberty and apperance of stamen and pistil in plants.

(3) It occurs in higher plants and animals.

(4) It involves fertilisation or fusion of male and female gametes, giving rise to zygote.

(5) Characteristics of both the parents are inherited in the developing embryo.

(6) Parents remain alive after the process of reproduction

 

6. 6. (a) Draw in sequence, different stages of binary fission in Amoeba.

(b) What is vegetative propagation ?

 

Ans.