Access Class 10 Science Chapter 7 How do Organisms Reproduce? Question Answer (Intext Exercise)
Here are the step-by-step solutions to all the exercise questions that help in revising the concepts. Students can use the Class 10 Science Chapter 7 How do Organisms Reproduce? question answers.
Topic 7.1 Do organisms create exact copies of themselves
Q1. What is the importance of DNA copying in reproduction?
Answer:
The importance of DNA replication in reproduction is as follows:
It allows offspring to inherit traits from their parents.
It helps keep the species' characteristics the same over time.
Small errors during DNA copying lead to variations within a species, which are important for adaptation and evolution.
Q2. Why is variation beneficial to the species but not necessarily to the individual?
Answer:
Variation is useful to a species as it allows some individuals to adapt to changes in their environment, which helps the survival of the species. As an example, if there were an outbreak of disease, those with genetic resistance would be able to survive and reproduce. Variation, though, is not always profitable to an individual, as certain differences could make survival more difficult for some organisms.
Topic 7.2 - Modes of Reproduction Used by Single Organisms
Q1. How does binary fission differ from multiple fission?
Answer:
The difference between binary fission and multiple fission is given below:
Binary Fission | Multiple Fission |
One organism splits into two daughter cells. | One organism divides into many daughter cells. |
Common in Amoeba. | Seen in some protozoa, like Plasmodium. |
Simple and quick division. | More complex division results in many individuals at once. |
Q2. How will an organism benefit if it reproduces through spores?
Answer:
Spore reproduction is a successful mode of survival and spreading in unfavorable conditions.
Spores can resist extreme conditions because of the thick covering walls.
They spread conveniently over distances, enabling the organism to grow in new areas.
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Q3. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Answer:
Regeneration is common in simpler organisms but is limited in complex organisms because of their body structure.
Q4. Why is vegetative propagation practised for growing some types of plants?
Answer:
Vegetative propagation is a method of asexual reproduction used in plant cultivation of desirable traits on an economic scale.
Q5. Why is DNA copying an essential part of the process of reproduction?
Answer:
DNA replication ensures the passing on of genetic information during reproduction for species continuity and adjustment.
It makes children inherit traits from their parents, making species characteristics consistent.
Mutations in DNA replication help species adapt and evolve in changing environments.
Topic 7.3 - Sexual reproduction
Q1. How is the process of pollination different from fertilisation?
Answer:
Fertilisation and pollination are the two most important processes of plant reproduction. Pollination is the movement of pollen, whereas fertilisation is gamete fusion.
Pollination: Movement of the pollen grains from the male element (anther) to the female element (stigma) of a flower.
Fertilisation: Male and female gamete fusion, resulting in the formation of a zygote, which is a process after pollination.
Q2. What is the role of the seminal vesicles and the prostate gland?
Answer:
The prostate gland and seminal vesicles are significant in male reproduction due to their role in secreting fluids that support and carry sperm.
Seminal Vesicles: Secrete a fructose-rich fluid that gives energy to sperm and aids in semen development.
Prostate Gland: Produces a fluid that assists in sperm protection and stimulation and adds to semen volume.
Q3. What are the changes seen in girls at the time of puberty?
Answer:
Puberty results in various physical and emotional modifications in women as they grow into adults.
Q4. How does the embryo get nourishment inside the mother’s body?
Answer:
The embryo is supported by the placenta, which links it to the mother's bloodstream.
Q5. If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?
Answer:
A copper-T is an intrauterine device (IUD) for contraception, but it does not offer protection against sexually transmitted diseases (STDs).
Get Class 10 Science How do Organisms Reproduce? Question Answer (Chapter-End Exercise)
Q1. Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
Answer:
Budding is a form of asexual reproduction where a new organism develops from a part of the parent.
The correct answer is Option (b) Yeast.
Q2. Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
Answer:
Understanding the components of the female reproductive system is essential for biology.
The correct answer is Option (c) Vas deferens.
Q3. The anther contains
(a) sepals.
(b) ovules.
(c) pistil.
(d) pollen grains.
Answer:
The anther is an important part of the flower involved in reproduction.
The correct answer is Option (d) Pollen grains.
Q4. What are the advantages of sexual reproduction over asexual reproduction?
Answer:
Sexual reproduction produces variation due to the mixing of genes from two parents. This variation helps species adapt and survive in changing environments. It also reduces the chances of genetic diseases being passed on directly.
Q5. What are the functions performed by the testis in human beings?
Answer:
The testes have important functions in male reproductive health and function.
They produce sperm cells required for reproduction.
They secrete hormones, mainly testosterone, which control male characteristics and reproductive functions.
Q6. Why does menstruation occur?
Answer:
Menstruation is a natural phenomenon that occurs in women as part of the reproductive cycle.
Q7. Draw a labelled diagram of the longitudinal section of a flower.
Answer:
A labelled diagram of a flower typically includes various parts such as petals, sepals, stamens, and pistils.
Labelled diagram of the longitudinal section of a flower
![LS OF FLOWER]()
Q8. What are the different methods of contraception?
Answer:
Methods of contraception prevent pregnancy and can be very diverse in method.
Barrier methods (such as condoms), hormonal methods (such as the pill), and intrauterine devices (IUDs) are a few examples.
Natural methods involve monitoring ovulation and avoiding sex during fertile times.
Q9. How are the modes of reproduction different in unicellular and multicellular organisms?
Answer:
Difference between the mode of reproduction in a unicellular and a multicellular organism-
UNICELLULAR ORGANISMS | MULTICELLULAR ORGANISMS |
1. Mainly reproduce asexually (e.g., binary fission). 2. Only one Parent is required to produce offspring. 3. No special cells and organs are present for reproduction. | 1. Mainly reproduce sexually. However, they can also reproduce asexually (e.g., vegetative propagation in plants). 2. A male and a female are both required in this method. 3. Special cells and organs are present for reproduction |
Q10. How does reproduction help in providing stability to populations of species?
Answer:
Reproduction is required to sustain healthy species populations over the long term.
It allows for population growth, which ensures species can survive environmental changes.
Reproduction also allows for genetic diversity, enhancing adaptability and resistance to disease.
Q11. What could be the reasons for adopting contraceptive methods?
Answer:
Individuals use contraceptive methods for different personal and health-related reasons.
Important Questions from Class 10 Chapter 7 How do Organisms Reproduce?
Given below is a question from the chapter, along with the detailed solution. Practising different forms of questions improves confidence. All types of questions are included in the NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce?
Question 1: Embryo receives the nutrition for growth from:
Options
Uterine wall
Ovary
Placenta
None of the above
Answer: An embryo receives its nutrients from the mother through a special tissue called the placenta. The placenta is a temporary organ that develops during pregnancy and connects the embryo to the mother’s uterus. It not only supplies nutrients and oxygen but also removes waste products from the embryo’s blood.
Hence, the correct answer is option (3), Placenta.
Question 2: How does the uterus change to attach the fertilised egg to its wall?
Options
The uterine wall becomes thin
The uterine wall becomes thick
The uterine wall does not change
None of the above
Answer: After fertilisation, the uterine wall thickens due to increased blood supply and tissue growth. This helps in providing a suitable environment for the fertilized egg to attach and develop into an embryo. The thickened wall also nourishes the developing embryo.
Hence, the correct answer is option (2). The uterine wall becomes thick.
Question 3: Fertilisation of male and female germ cells takes place in:
Options
Ovary
Fallopian tube
Uterus
Vagina
Answer:
Fertilisation occurs when the male sperm cell meets the female egg in the fallopian tube. The tube provides the right environment for the sperm to reach and fuse with the egg, forming a zygote.
Hence, the correct answer is option (2). Fallopian Tube.
Question 4: Surgical methods to avoid unwanted pregnancy are:
Options
Cutting and sealing of the male reproductive tube carrying the sperm
Removal of the female uterus
Abortion
All of the above
Answer:
All the given options that are cutting and splitting the male reproductive tube carrying the sperm, removal of the uterus and abortion are the surgical methods of avoiding unwanted pregnancy.
Hence, the correct answer is option (4). All of the above.
Question 5: The development of the secondary sexual characters is the indication of:
Options
A female can give birth to a baby
A male can produce the germ cells
An organism is capable of carrying out sexual reproduction
All of the above
Answer:
A female giving birth to a baby, a male producing germ cells, and an organism carrying out sexual reproduction are initiated at the age of puberty, which is indicated by the secondary sexual characteristics.
Hence, the correct answer is option (4). All of the above.
Question 6: The fusion of the gametes only takes place inside the organism. True or False
Options
1. True
2. False
Answer:
The fusion of the organism can take place either inside or outside the organism. Hence, the given statement is incorrect.
Hence, the correct answer is option (2). False.
Question 7: Changes that is not part of reproductive growth is:
Options
1. Growth of hair around the genital areas
2. Increase in the overall size of the body in sexual reproduction
3. Increase in the size ofthe reproductive external organ
4. Eruption of pimples on the skin
Answer:
An increase in the overall body size is part of vegetative growth, and hence option 2 is correct.
Hence, the correct answer is option (2). Increase in the overall size of the body through sexual reproduction.
Question 8: What is a pollen tube?
Options:
Holes in the pollen grain
Tube-like structure below the stigma
Tube like structure extending from the pollen grain inside the stigma
None of the above
Answer:
Pollen tube is the extension of the pollen grain that takes place inside the stigma to carry the male gamete to the egg cell to cause fertilization. Hence, option 3 is correct.
Hence, the correct answer is option (3), Tube like structure extending from the pollen grain inside the stigma
Question 9: Which of the following is the male reproductive part?
Options:
Carpel
Stamen
Petals
Sepals
Answer:
Stamen is the male reproductive part and hence option 2 is correct.
Hence, the correct answer is option (2) Stamen