How Do Organisms Reproduce Important Questions Class 10 Science

Reproduction is the biological process by which living organisms produce offspring, ensuring the continuity of their species. It is a fundamental feature of life, enabling species to adapt, survive, and evolve over generations. Class 10, Chapter 7, How Do Organisms Reproduce, deepens into the mechanisms of reproduction in plants and animals, highlighting the broad reproductive strategies and their importance in sustaining life on Earth.

This blog summarises the important concepts and questions to help you prepare thoroughly for your Class 10 Exams 2025. By understanding the concepts provided in this chapter you understand how organisms really reproduce and what processes are followed in the formation of a new organism or Human Being and many Important Questions of Chapter 7 Class 10 Science are framed in final examinations. Thus, understand the concepts provided in this chapter to their core if you are an aspiring doctor.

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Chapter 7 How Do Organisms Reproduce Important Questions

1. Planarians can regenerate lost body parts due to the presence of specialised cells called neoblasts. These specialised cells multiply and make a large mass of cells from which different cells undergo changes to become different types of cells and tissues.

(a) In plants, in which type of tissue are cells that have a function similar to neoblasts found?

(b) How do the characteristics of a planarium formed by regeneration compare with the characteristics of the original planarium? Justify your answer.

Answer:

(a) In plants, the tissue containing cells with a function similar to neoblasts is the meristematic tissue.

Meristematic tissues consist of undifferentiated, actively dividing cells that can develop into various types of cells and tissues, similar to how neoblasts function in planarians. Examples include the apical meristem, lateral meristem, and intercalary meristem, which contribute to growth and repair in plants.

(b) The characteristics of a planarian formed by regeneration are identical to the original planarian.

Justification: Regeneration in planarians relies on the neoblasts, which are totipotent stem cells. These cells contain the complete genetic information required to recreate all the tissues and structures of the original organism. Thus, the regenerated planarian has the same structural and functional characteristics as the original one, provided the regeneration process is complete and accurate.

2. What could be the TWO most likely reasons for unicellular organisms to reproduce only through asexual reproduction?

Answer:

The two most likely reasons for unicellular organisms to reproduce only through asexual reproduction are:

1. Simplicity and Efficiency

Asexual reproduction, such as binary fission, is a straightforward and rapid process. It requires only one parent and involves simple cell division, allowing unicellular organisms to reproduce quickly and efficiently without the need for complex structures or processes. This efficiency is crucial for survival in environments with abundant resources or where rapid population growth is advantageous.

2. Genetic Stability

Unicellular organisms often rely on asexual reproduction to maintain genetic consistency across generations. This ensures that well-adapted traits suited to their environment are preserved without the potential disruptions caused by genetic recombination in sexual reproduction.

These factors enable unicellular organisms to thrive in diverse and often rapidly changing environments.

3. A farmer bought some strawberries and liked the taste. He decided to grow his own strawberries that should have the same taste.

(a) Which method of cultivation should the farmer adopt?

(b) Why would the farmer choose this method?

Answer:

(a) The farmer should adopt vegetative propagation (specifically, using runners or stolons).

• Runners are horizontal stems that grow from the parent strawberry plant. These runners develop into new plants, ensuring that the offspring are genetically identical to the parent plant.

(b) The farmer would choose this method because:

• Cloning of desirable traits: By using vegetative propagation, the farmer ensures that the new plants are genetically identical to the parent plant, which means they will have the same taste and other desirable characteristics.
• Consistency in quality: Since the farmer liked the taste of the strawberries, using runners guarantees that the taste will remain consistent across all the new plants, as they are clones of the original plant.

4. Plants produced through vegetative propagation are genetically identical to their parents.

What could be the biggest disadvantage of vegetative propagation?

Answer:

The biggest disadvantage of vegetative propagation is the lack of genetic diversity.

Since plants produced through vegetative propagation are genetically identical to their parents, they are clones. This means they do not have the genetic variation needed to adapt to changing environmental conditions, such as new pests, diseases, or shifts in climate. If one plant is susceptible to a disease or adverse condition, all the plants produced through vegetative propagation will likely share the same vulnerability, potentially leading to a higher risk of crop failure or population decline.

5. 'In vitro fertilisation' is a process of fusing a human egg and sperm outside a woman's body, in a laboratory. After fertilisation, the zygote is allowed to develop into an embryo for 2-6 days. The embryo is then implanted in the woman's uterus, where it develops normally.

Which labelled region in the diagram BEST represents reproduction via in vitro fertilisation?

Answer:

In the process of in vitro fertilization (IVF), fertilization occurs outside the body in a laboratory setting, but implantation happens inside the body in the woman's uterus.

Based on this description, the best labelled region in the diagram to represent reproduction via in vitro fertilization would be the region that indicates fertilization outside the body (such as the laboratory setting where the sperm and egg meet), and then the region showing implantation in the uterus where the embryo is placed for further development.

In diagrams illustrating the human reproductive system or fertilization processes, this would correspond to:

• Fertilization happening in a lab or external environment (outside the woman's body).
• Implantation in the uterus after embryo development.

So, the labelled region representing the fertilization outside the body and subsequent implantation would be the most accurate representation of in vitro fertilization.

6. Bindu wants to produce a hybrid variety of tomatoes. She has tomato plants X and Y belonging to two different varieties, one with smooth, long fruits and the other one with wrinkled, round fruits.

Tomatoes have bisexual flowers. Bindu carries out the following steps carefully to cross pollinate the flowers of plants X and Y:

a. She removes a part of the flowers of tomato plant X just before the flowers bloom.

b. She manually pollinates the flowers of tomato plant X using pollen from the flowers of tomato plant Y.

c. She ties small plastic bags around the pollinated flowers of tomato plant X. The plastic bags are removed after a couple of days.

Bindu carried out step 1 so as to prevent self-pollination. Which part did she remove?

Answer:

To prevent self-pollination in the tomato flowers of plant X, Bindu likely removed the anthers from the flowers of tomato plant X in step 1.

Explanation:

• The anthers are the male reproductive parts of a flower that produce pollen. By removing the anthers, Bindu ensured that plant X could not self-pollinate because it would not have its own pollen available for fertilization.
• This step is crucial in cross-pollination because it forces Bindu to manually pollinate the flowers using pollen from plant Y, ensuring that the offspring will be a hybrid of the two tomato plants.

By removing the anthers, Bindu effectively prevents self-pollination and ensures that only the pollen from plant Y can fertilize the flowers of plant X, leading to hybrid offspring.

7. The description of a species of fish called 'guppy' is given below:

"Guppies are live-bearing fish, with a gestation period of 21-30 days. Once inseminated, female guppies can store sperm in their ovaries, which can continue to fertilize ova up to eight months, meaning the female mate can give birth to the male's offspring long after the male's death."

(a) Based on the given information, which labelled regions CAN guppies belong to? 

(b) What additional information is required to identify the labelled region in the diagram that guppies ACTUALLY belong to?

Answer:

(a) Based on the given information, guppies can belong to the live-bearing fish region.

• Guppies are described as live-bearing fish (they give birth to live young, not lay eggs), which means they fall under a category of fish that reproduce through internal fertilization and give birth to fully developed young.

(b) The additional information required to identify the labelled region in the diagram where guppies actually belong would include:

• Taxonomic classification: To identify the exact region in a diagram, we would need to know the family, order, or class of the guppy. Guppies belong to the family Poeciliidae and the order Cyprinodontiformes.
• Reproductive mode: Although guppies are live-bearing, this characteristic alone might not fully specify the region of classification. We would need to check if the region being considered distinguishes between live-bearing species and egg-laying species, or if it includes specific reproductive characteristics like sperm storage and extended fertilization periods.

Therefore, additional information about the specific classification (family or order) and reproductive features would help pinpoint the exact region where guppies belong in the diagram.

8. Two statements are given - one labelled Assertion (A) and the other labelled Reason (R). Read the statements carefully and choose the option that correctly describes statements A and R.

Assertion (A): Oral contraceptive pills and copper-T do not prevent sexually transmitted diseases.Reason (R): Sexually transmitted disease are transmitted by contact with mucous membranes of infected organs.

a. Both A and R are true and R is the correct explanation of A.

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.

Answer:(b) Both A and R are true but R is not the correct explanation of A.

Explanation:

Assertion (A): "Oral contraceptive pills and copper-T do not prevent sexually transmitted diseases."

This statement is true because oral contraceptive pills and copper-T (IUD) are designed to prevent pregnancy, not sexually transmitted diseases (STDs). They do not provide protection against infections like HIV, gonorrhea, or chlamydia, which are transmitted through sexual contact.

Reason (R): "Sexually transmitted diseases are transmitted by contact with mucous membranes of infected organs."

This statement is also true. STDs are primarily transmitted through the exchange of bodily fluids (semen, vaginal fluids, blood, etc.) during sexual contact, which involves the mucous membranes of reproductive organs, and sometimes oral or anal regions.

While both statements are true, the reason provided does not directly explain why oral contraceptives and copper-T do not prevent STDs. These methods work to prevent pregnancy, not infection, so R does not fully explain A.

9. The biological sex of an individual only depends on the sperm cell."

Is the above statement true or false? Justify your answer.

Answer:

The statement "The biological sex of an individual only depends on the sperm cell" is false. Biological sex determination typically depends on the combination of sex chromosomes inherited from both the egg cell (from the mother) and the sperm cell (from the father).

The egg cell always contributes an X chromosome.

The sperm cell can contribute either an X or a Y chromosome.

• If the sperm carries an X chromosome, the resulting offspring will be female (XX).
• If the sperm carries a Y chromosome, the resulting offspring will be male (XY).

Thus, the biological sex of an individual is determined by both the egg cell and the sperm cell, but the sperm cell plays a key role in determining whether the individual is male or female, depending on whether it carries an X or Y chromosome. Therefore, the statement is inaccurate since it only attributes sex determination to the sperm cell, ignoring the contribution of the egg.

10. In the diagram below, each labelled region (P to W) represents a certain combination of reproductive processes found in an animal. Each labelled region is characterised by the different circles that it is (or is not) a part of.

Answer the following questions based on this diagram.

Name any one animal whose mode of reproduction is represented by region P.

Answer:

The area labeled P in the diagram refers to internal fertilization.

Internal fertilization is a type of sexual reproduction where the sperm and egg unite inside the female's body. This process occurs in humans.

Summary of Ch 7 Reproduction CBSE Class 10 

Reproduction is important because:

1. Continuation of Species - Making sure of the survival by producing offspring.
2. Genetic Variability - Especially in sexual reproduction, which contributes to evolution.
3. Adaptation and Survival - Variations that arise during reproduction help species adapt to environmental changes.

Types of Reproduction

Organisms reproduce in two significant ways - Asexual Reproduction and Sexual Reproduction.

Asexual Reproduction

In asexual reproduction, a single parent produces offspring without the involvement of gametes. The offspring are genetically identical to the parent. This method is standard for simpler organisms like bacteria, algae, fungi, and plants.

Methods of Asexual Reproduction

Binary Fission - The parent organism splits into two identical daughter cells. Example: Amoeba, paramecium.

Fragmentation - The organism's body breaks into fragments, each developing into a new organism. Example: Spirogyra, flatworms.

Budding - A small bud grows on the parent organism, matures, and detaches to form a new individual. Example: Yeast, hydra.

Vegetative Propagation - New plants grow from vegetative parts like roots, stems, or leaves. Example:

• Stem: Potato, sugarcane.
• Leaves: Bryophyllum.

Spore Formation: Organisms produce spores, which are dispersed and grow into new individuals under favourable conditions. Example: Fungi, mosses.

Sexual Reproduction

Sexual reproduction involves two parents contributing genetic material through specialized cells called gametes. It results in offspring with genetic variations, making it more advantageous for evolution.

Sexual Reproduction in Plants:

In plants, sexual reproduction occurs through flowers, which are the reproductive organs.

Structure of a Flower:

• Male Part - Stamen (comprising the anther and filament). The anther produces pollen grains, which contain male gametes.
• Female Part - Carpel/Pistil (consisting of the stigma, style, and ovary). The ovary houses ovules, which contain female gametes.

Processes in Sexual Reproduction:

Pollination - The transfer of pollen from the anther to the stigma. Its various types are:

• Self-pollination: Pollen from the same flower or plant.
• Cross-Pollination: Pollen from a different plant of the same species.

Fertilization - After pollination, male gametes from pollen grains fuse with female gametes in the ovule to form a zygote. The zygote develops into a seed, and the ovary grows into a fruit.

Sexual Reproduction in Animals

Sexual reproduction in animals involves the formation of male and female gametes, their fusion (Fertilization), and the subsequent development of a new individual.

Male Reproductive System

• Testes: Produce sperm and testosterone.
• Vas Deferens: Transports sperm from the testes.
• Penis: Facilitates sperm transfer.

Female Reproductive System:

• Ovaries: Produce eggs and female hormones (estrogen and progesterone).
• Fallopian tubes are the site of Fertilization where sperm meets egg.
• Uterus: Where the zygote develops into an embryo.
• Vagina: Birth canal and receptacle for sperm.

Fertilization:

External Fertilization: Happens outside the body (e.g., fish, frogs).

Internal Fertilization happens inside the female body (e.g., humans and mammals).

DNA Copying and Variations

During reproduction, DNA copying ensures the transfer of genetic material to offspring.

Accuracy: Essential for maintaining the integrity of species characteristics.

Variations: Arise due to minor errors in copying or genetic recombination, contributing to diversity and evolution.

Reproductive Health

Reproductive health is vital to this chapter, covering the importance of maintaining safe reproductive practices.

Key Topics:

Contraceptive Methods:

• Barrier methods (e.g., condoms).
• Hormonal methods (e.g., birth control pills).
• Surgical methods (e.g., vasectomy, tubectomy).

Sexually Transmitted Diseases (STDs):

• Examples: AIDS, syphilis, and gonorrhoea.
• Prevention: Safe sexual practices and regular health checkups.

Family Planning:

• Promotes better reproductive health and population control.

Study Tips for CBSE Class 10 Chapter 7

By following these tips, you'll be well-prepared to tackle any question from Chapter 7 in your exams. Make a study plan, practice consistently, and review your progress regularly. Read below:

• Diagrams are a crucial part of Chapter 7. Pay special attention to the structure of a flower, reproductive systems in plants and animals, and processes like binary fission in microorganisms.
• Label diagrams accurately and practice drawing them multiple times. Well-drawn and labelled diagrams can fetch you extra marks in exams.
• Start with the NCERT textbook exercises at the end of the chapter. They are essential for understanding the fundamental question formats and common topics.
• Don't skip the NCERT Exemplar problems—they provide a mix of application-based and higher-order thinking questions crucial for exams.
• Focus on understanding the mechanisms of pollination and Fertilization. Create flowcharts or step-wise notes to simplify these processes.
• Learn the role and importance of DNA copying during reproduction. Grasp how it ensures the continuity of species while introducing variations.

This chapter not only explores the biology of reproduction but also puts tremendous pressure on its significance in life's continuity and evolution. From understanding the mechanisms of asexual reproduction to learning about the complexity of sexual reproduction in plants and animals, this chapter builds a strong foundation in biology.

Reproduction is the essence of life—understanding it empowers us to appreciate the diversity of living organisms and their survival strategies. Start revising now and ensure you're prepared to tackle any question - come what may!

We hope that you practise the above Chapter 7 Class 10 Science Important Questions and achieve your dream marks.

All the best!