Reproduction (Class 10) Top 30 short answer Questions

 Hello, my brilliant students!

Welcome back! You've expertly navigated the 1-mark and 2-mark questions, and I'm so proud of the foundation you've built. Now, it's time to dive deeper into the core concepts of the chapter.

This post is all about the Short Answer (SA) questions, each worth 3 marks. These questions are the heart of the exam paper and require you to explain concepts with clear, structured points, often involving diagrams or differentiation. This is where you really get to show what you know! Let's conquer the top 30 questions.

Section A: Asexual Reproduction (Q1-Q10)

Q1. Draw a neat diagram to show the process of budding in Hydra and explain the process. Answer: Budding in Hydra is an asexual method:

1. Due to repeated cell division at a specific site, a small outgrowth called a bud develops on the parent's body.

2. The bud gradually grows and develops features of the parent, like a mouth and tentacles.

3. Once fully mature, the bud detaches from the parent and becomes a new, independent individual.

Q2. Differentiate between Binary Fission and Multiple Fission, giving one example for each. Answer:

Binary Fission	Multiple Fission
The parent cell divides into two equal daughter cells.	The parent cell divides into many daughter cells simultaneously.
It occurs under favourable conditions.	It occurs under unfavourable conditions (inside a protective cyst).
Example: Amoeba and Leishmania.	Example: Plasmodium (malarial parasite).

Q3. Explain spore formation in Rhizopus with a labeled diagram. Answer: Rhizopus (bread mould) reproduces using spores.

1. The thread-like structures called hyphae develop vertical stalks ending in a spherical structure called sporangium.

2. Inside the sporangium, the nucleus divides repeatedly to form many tiny spores.

3. When the sporangium bursts, the spores are released and germinate into new individuals under moist conditions.

Q4. State the difference between fragmentation and regeneration, giving an example of an organism for each. Answer: | Fragmentation | Regeneration | | :--- | :--- | | Occurs in simple organisms (Spirogyra); the body naturally breaks upon maturation. | Primarily a repair/regrowth mechanism (Planaria); any cut piece can form a whole organism using specialized cells. | | Every fragment is a reproductive unit. | Requires specialized cells; not every piece may survive to reproduce. |

Q5. State three advantages of vegetative propagation in plants. Answer:

1. Plants grown this way can bear flowers and fruits much earlier than those grown from seeds.

2. It is the only way to propagate plants that have lost the capacity to produce viable seeds (e.g., banana, orange).

3. It helps in the production of genetically uniform individuals (clones) having all the desired traits of the parent plant.

Q6. Describe two artificial methods of vegetative propagation in brief. Answer:

1. Cutting: A small piece of the stem with some buds is cut and planted in the soil. It develops roots and grows into a new plant (e.g., Rose, Sugarcane).

2. Grafting: The desired shoot (scion) from one plant is joined to the rooted stem (stock) of another. The tissues fuse to form a composite plant with the traits of the scion (e.g., Mango, Apple).

Q7. What is the role of DNA copying in reproduction? Why is it not a perfectly accurate process? Answer: The role of DNA copying is to ensure the transmission of the parent's body design and characteristics to the offspring. It is not perfectly accurate because the biochemical reactions involved in replication introduce small errors or changes (variations), which are essential for evolution and the survival of the species.

Q8. Why is variation important for the survival of a species but not necessarily for the individual? Answer: Variation is important for the species because it creates a diverse population. If the environment changes, some individuals will have variations that allow them to survive and reproduce, thus preventing the extinction of the entire species. For the individual, a variation might be beneficial (survival) or lethal (death).

Q9. Give reasons why organisms like Amoeba and Hydra do not face the problem of competition from their own species as severe as in seed-bearing plants. Answer: Amoeba and Hydra generally reproduce asexually, which is very rapid. However, they are mobile (Amoeba) or live in fluid environments (Hydra), allowing the offspring to move away quickly. Seed-bearing plants, especially when seeds are not dispersed well, face intense competition for light, water, and nutrients in the limited area around the parent.

Q10. Explain the process by which Bryophyllum reproduces asexually. Answer: Bryophyllum reproduces by leaf buds.

1. The leaves of the Bryophyllum plant have small notches along the margin.

2. In these notches, adventitious buds develop.

3. When a mature leaf falls on moist ground, these buds detach from the leaf and grow into new, independent plantlets.

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Section B: Sexual Reproduction in Plants (Q11-Q20)

Q11. Draw a neat diagram of the longitudinal section of a flower and label the Stigma, Style, and Ovary. Answer:

Q12. What is pollination? State the difference between self-pollination and cross-pollination. Answer: Pollination is the transfer of pollen grains from the anther to the stigma.

• Self-Pollination: Transfer of pollen occurs within the same flower or between two flowers on the same plant.

• Cross-Pollination: Transfer of pollen occurs between the anther of one plant and the stigma of a genetically different plant of the same species.

Q13. Describe the journey of a pollen grain from the stigma to the ovule. Answer:

1. Upon landing on the stigma, the pollen grain absorbs moisture and nutrients and germinates.

2. It grows a long tube called the pollen tube, which carries the male gametes.

3. The pollen tube grows down through the style and enters the ovule, allowing the male gamete to reach the female egg cell for fertilization.

Q14. What changes are observed in the flower after fertilization? (3 changes) Answer:

1. The ovule develops a tough coat and transforms into the seed.

2. The ovary grows rapidly and ripens to become the fruit.

3. The sepals, petals, stamens, style, and stigma usually shrivel and fall off.

Q15. Why is sexual reproduction considered superior to asexual reproduction for the survival of a species? Answer: Sexual reproduction is superior because:

1. It combines DNA from two parents, resulting in a much greater range of variation in the offspring.

2. This variation helps the species adapt better to unpredictable changes in the environment (e.g., disease, climate change).

3. The accumulation of these beneficial variations over time drives evolution.

Q16. Name and describe the parts of a seed that contribute to the new plant and its initial food supply. Answer:

1. Embryo (Future Plant): The embryo contains the Plumule (future shoot/stem) and the Radicle (future root).

2. Cotyledons (Food Supply): These are seed leaves that store food for the developing embryo until the plant can produce its own food through photosynthesis.

Q17. List three ways by which pollen grains are transferred in cross-pollination, giving an example for each. Answer:

1. Wind: Pollen is light and dust-like (e.g., Grasses, Maize).

2. Water: Pollen floats on the water's surface (e.g., Aquatic plants like Vallisneria).

3. Insects/Animals: Flowers are bright and scented to attract insects and animals that carry the sticky pollen (e.g., Rose, Sunflower).

Q18. State three functions of the placenta in human females. Answer:

1. Nutrition: It provides glucose and nutrients from the mother's blood to the developing embryo.

2. Respiration: It supplies oxygen to the embryo and removes carbon dioxide from the embryo's blood.

3. Excretion: It transports waste products (like urea) from the foetal blood to the mother's blood for removal.

Q19. What is the fate of the ovule and the ovary after the process of fertilization in a flower? Answer:

1. The Ovule, after fertilization, becomes the seed. The seed protects the embryo inside a tough seed coat.

2. The Ovary, after fertilization, swells up and develops into the fruit, which often serves to protect the seeds and aid in their dispersal.

Q20. Why must organisms reproduce? Give two main reasons. Answer:

1. Continuity of Species: Reproduction ensures the perpetuation of a species, generation after generation, preventing it from becoming extinct.

2. Replacement of Dead Individuals: As organisms die, reproduction creates new individuals to take their place, maintaining the population size.

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Section C: Human Reproduction & Health (Q21-Q30)

Q21. What is puberty? List two changes that are common to both boys and girls during this period. Answer: Puberty is the period during adolescence when the body reaches sexual maturity, and the reproductive organs become functional. Two common changes:

1. Growth of thick, dark hair in the armpit and genital regions.

2. Increased activity of oil and sweat glands, often leading to acne/pimples.

Q22. What are the three primary functions of the testes in the human male? Answer:

1. Sperm Production: Production of the male gametes (sperm).

2. Testosterone Secretion: Secretion of the male sex hormone, Testosterone.

3. Temperature Control: Located in the scrotum, which keeps the testes outside the body cavity to maintain the optimum low temperature necessary for sperm production.

Q23. Describe the role of the seminal vesicles and the prostate gland. Answer: The seminal vesicles and the prostate gland are accessory glands that produce and secrete fluids that combine with the sperm to form semen.

• Role 1: The fluid provides nutrition (like fructose) to the sperm, giving them energy for movement.

• Role 2: It makes the transport of sperm easier by providing a fluid medium.

• Role 3: The alkaline nature of the fluid neutralizes the acidity of the path, protecting the sperm.

Q24. Explain the process of fertilization in humans and where it occurs. Answer: Fertilization is the fusion of the male gamete (sperm) with the female gamete (egg).

1. It occurs in the Oviduct (Fallopian Tube).

2. One sperm penetrates the egg.

3. The nuclei of the sperm and egg fuse to form a single cell called the zygote.

Q25. What happens to the lining of the uterus if the egg is not fertilized? Answer: If the egg is not fertilized:

1. The thickened, spongy uterine lining, which was prepared to receive the embryo, is no longer needed.

2. This lining breaks down and is discharged from the body through the vagina.

3. This process, along with blood and mucous flow, is called menstruation.

Q26. What are Sexually Transmitted Diseases (STDs)? Name one bacterial and one viral STD. Answer: STDs are infections that are transmitted from an infected person to a healthy person through sexual contact.

• Bacterial STD: Syphilis or Gonorrhoea.

• Viral STD: HIV-AIDS or Genital Warts.

Q27. Why are barrier methods of contraception preferred over chemical methods? (3 reasons) Answer:

1. Barrier methods (Condoms/Diaphragms) have fewer side effects compared to hormonal chemical methods (pills).

2. They offer protection not only against unwanted pregnancy but also against the spread of STDs (like HIV-AIDS).

3. They are easier to stop and start compared to pills, which require strict daily adherence.

Q28. Briefly explain the difference between a vasectomy and a tubectomy. Answer: These are both surgical, permanent methods of contraception.

• Vasectomy (in males): The vas deferens is cut or blocked, preventing sperm from being carried to the outside.

• Tubectomy (in females): The oviducts (fallopian tubes) are cut or blocked, preventing the egg from reaching the uterus and preventing sperm from reaching the egg.

Q29. Give the full form of IUDs and explain how they prevent pregnancy. Answer: The full form of IUDs is Intra-Uterine Devices (e.g., Copper-T).

1. Mechanism 1: They are inserted into the uterus and make the uterus unsuitable for implantation of the embryo.

2. Mechanism 2: Some IUDs (like Copper-T) release copper ions that make the sperm ineffective and reduce their fertilizing capacity.

Q30. Differentiate between a zygote and an embryo. Answer:

1. Zygote: It is the single-celled structure formed immediately after the fusion of the sperm and the egg (fertilization).

2. Embryo: It is the multicellular structure formed from the zygote after repeated mitotic cell divisions (cleavage) have occurred. The embryo eventually implants in the uterus.

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You've completed the biggest list of questions in the entire series! Give yourself a high five! You're building a massive resource that will guarantee success for any student.

Next up, we'll tackle the last two types of questions: the 5-mark Long Answer Questions and the modern Case-Based Questions. You're on the home stretch! 🌟

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