Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

NCERT Solutions for Class 10 Science Chapter 7 – How do Organisms Reproduce

Best NCERT Solutions for Class 10 Chemistry Chapter 7 How do Organisms Reproduce .One essential biological mechanism that keeps species alive is reproduction. It permits genetic material to be passed down from one generation to the next, facilitating gradual evolution and adaptability. This chapter explores the several forms of reproduction that can be found in nature, examining the distinctions between asexual and sexual reproduction, the underlying mechanisms, and the evolutionary benefits of each.

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

Answer: DNA, or deoxyribonucleic acid, is the genetic material found in chromosomes and is found in the nucleus of a cell. DNA carries genes, which are in charge of all an individual’s physiological functions. A child inherits two copies of DNA, one from the mother and one from the father.

This explains why children resemble their parents so much. Thus, one important process by which traits are transmitted down across the generations is DNA copying during reproduction.

The accuracy of DNA copying occurs during reproduction. Therefore, during reproduction, DNA copying is crucial. Because DNA copying results in variances in sexually reproducing organisms, species differ in their ability to survive.

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

Answer: When environmental conditions drastically change and a species’ survival becomes more challenging, variations might occasionally be advantageous to the species. For instance, the majority of the bacteria in the water would perish if the temperature were to suddenly rise. Few varieties would be able to endure, and those that do are heat-resistant.

But without these variations, the entire bacterial population would be wiped out. Variants therefore aid in the species’ survival. But not every variation is advantageous to a particular organism.

3. How does binary fission differ from multiple fission?

Answer: In binary fission, a single cell divides into two equal cells. Amoeba and Bacteria: Both amoeba and bacteria divide by binary fission.

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

Multiple fission is the division of a single cell into numerous daughter cells at the same time. Plasmodium and amoeba split by multiple fission.

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

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

Answer: Spores are hard, dormant structures that some organisms create. They are created to temporarily counteract adverse circumstances. As a result, it becomes simpler for the spores to spread and aid in pollination.

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

Answer: Hydra and planaria are examples of simple organisms that may regenerate to create new individuals. We refer to the new creatures made from its body parts as regeneration.

Certain organisms can use this in their reproduction process because every component of their body is generated by growth and development and because their entire body is composed of fewer and identical types of cells. Nonetheless, complex organisms exhibit the organ-system level of organisation.

All organisms’ bodies function as a single, integrated system. Their lost bodily parts, like as blood, muscles, skin, etc., can regenerate. However, since a single cell or tissue cannot create an entire organ, regeneration is not a viable means of creating new persons.

Consequently, it is impossible for a full new organism to regenerate completely. Certain organisms, including starfish and lizards, have the ability to regrow damaged body parts.

6. Why is vegetative propagation practiced for growing some types of plants?

Answer: Vegetative propagation is asexual reproduction carried out via the plant’s vegetative parts (leaf, stem, and roots). This type of self-sustaining growth doesn’t require seeds to take place. It offers several benefits, including:

1. Plants like orchids, bananas, etc. that don’t produce viable seeds are dispersed.

2. Propagation of a particular superior variety of plant, as the offspring will genetically resemble the parent plant.

3. A speedier propagation technique can produce a lot of plants in a short amount of time.

4. Plant introduction and propagation in more recent places where soil or environmental factors may prevent seeds from germinating.

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

Answer: Since genetic information is transferred from parents to children, DNA (deoxyribonucleic acid) replication is an essential component of reproduction. An individual’s body type is predetermined.

Through chemical reactions, the reproducing cells create a copy of their DNA, resulting in two copies of the DNA. DNA replication occurs with the synthesis of new cellular structures. The division of a cell into two occurs after this procedure.

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

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

Answer: The following distinguishes fertilisation from pollination:

Pollination	Fertilization
Pollination is the process of moving pollen from one flower to the stigma of another.	Pollination is followed by fertilisation. So, it is the combination of the gametes from the male and female.
Pollinating agents, like as water, air, birds, or insects, help to provide pollination.	The process of fertilisation occurs within the ovule and produces a zygote.

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

Answer: Sperm are lubricated by secretions from the prostate glands and seminal vesicles, which also offer a fluid medium for sperm transportation. In order to sustain the sperm for a few days until they can fertilise the egg, they also supply fructose, calcium, and certain enzymes to the flowing sperm.

10. What are the changes seen in girls at the time of puberty?

Answer: Girls’ secondary sexual traits:

The nipples located at the tips of the breasts develop darker in colour as breast size increases.

the presence of hair in the vaginal region.

hair on the face, hands, legs, and underarms, among other parts of the skin.

Both the uterus and the ovary grow in size.

the menstrual cycle beginning.

Because the skin is secreting more oil, pimples are starting to form.

Expanding the hip area

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

Answer: Within the mother’s body, the embryo develops over the course of around nine months, or 280 days. Within the uterus, the embryo encircled by the outer tissue grows projections that resemble fingers and are referred to as villi. The villi are surrounded by uterine tissue and maternal blood. They offer a substantial surface area for the exchange of nutrients and oxygen.

The placenta is a unique tissue that is embedded in the wall of the uterus. Through the placenta, the embryo receives oxygen and other nutrients from the mother’s blood. Waste products are also produced by the embryo and are eliminated by the placenta.

12. If a woman is using a copper−T, will it help in protecting her from sexually transmitted diseases?

Answer: No, Since a copper-T does not stop semen from entering the body, it cannot treat sexually transmitted infections. Only in the uterus is the embryo’s implantation stopped.

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

Exercise Questions

1. Asexual reproduction takes place through budding in

(a) Amoeba.

(b) Yeast.

(c) Plasmodium.

(d) Leishmania.

Answer: (b)

2. 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: (c)

3. The anther contains

(a) Sepals.

(b) Ovules.

(c) Carpel.

(d) Pollen grains.

Answer: (d)

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

4. What are the advantages of sexual reproduction over asexual reproduction?

Answer: Benefits of procreation by sexual means:

(i) Sexual reproduction reveals more variances. It guarantees species survival as a result. The recently developed individuals exhibit traits from both parents.

(ii) Variations in the sexual mode are more likely to occur than in the asexual mode because asexual reproduction requires DNA to work inside the inherited cellular apparatus.

(iii) Less children are created through sexual reproduction than through asexual reproduction.

5. What are the functions performed by the testis in human beings?

Answer: Man’s testes, a reproductive organ, are located outside the abdomen in a loose pouch known as the scrotum.

Testes’ purposes:

(i) Generate gametes

(ii) The secretion of a hormone called testosterone is what gives boys their secondary sexual traits.

6. Why does menstruation occur?

Answer: Every month after reaching puberty, females undergo a process known as the menstrual cycle in which they generate a developed egg cell.

(i) During this time, an ovary releases a developed egg.

(ii) If the egg is not fertilised and the uterine lining sheds, a new menstrual cycle starts.

(iii) A menstrual cycle typically lasts for 28 days.

Best NCERT Solutions for Class 10 Science Chapter 7 How do Organisms Reproduce

8. What are the different methods of contraception?

Answer: Contraception refers to a method of preventing conception. The following categories are commonly used to categorise contraceptive methods:

(i) Natural Method → This approach reduces the likelihood of sperm and ovum coming into contact. Using this procedure, sexual activity is avoided from day 10 to day 17 of the menstrual cycle. This is because ovulation can occur during this time, increasing the likelihood of fertilisation.

(ii) Barrier Method → With the help of barriers, the fertilised ovum and sperm are stopped in this approach. There are impediments for men and women alike. Condoms are thin rubber barriers that are used to cover the penis in men and the vagina in women.

(iii) Oral Contraceptives → This approach calls for the oral administration of pills or medications. These have trace amounts of hormones in them that stop eggs from releasing, which stops fertilisation.

(iv) Implants and Surgical Methods → To prevent conception, contraceptive devices like Copper-T or Loop are implanted within the uterus. A variety of surgical techniques can be modified to prevent gamete translocation. Vasectomy, also known as blocking the vas deferens, is necessary to stop the transmission of sperm. Similarly, a tubectomy, which involves closing a female’s fallopian tubes, prevents the egg from entering the uterus.

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

Answer: In unicellular organisms, the process of reproduction involves complete cell division. Multicellular creatures have specialised reproductive organs, but unicellular organisms often reproduce by fission, budding, etc.

As a result, complicated reproductive techniques including spore formation and vegetative propagation can be used for reproduction. Sexual reproduction is the mode of reproduction found in more sophisticated multicellular organisms, such as plants and humans.

10. How does reproduction help in providing stability to populations of species?

Answer: Living things procreate in order to maintain their particular species. By creating a new individual who resembles the parents, a species’ population is given stability. Consequently, reproduction ensures population stability for species. Furthermore, because of the variations, the species is ultimately better adapted to deal with changes in its environment.

11. What could be the reasons for adopting contraceptive methods?

Answer: The following factors contribute to the adoption of contraceptive methods:

I In order to avoid unintended pregnancies.

(ii) To control birthrate, population growth, or both.

(iii) To stop the spread of diseases acquired through intercourse.