Short Questions Answer
1. What is the importance of DNA copying in reproduction?
Answer: DNA copying ensures transfer of genetic information and body design from parents to offspring.
2. Why is variation beneficial to species?
Answer: Variation helps species survive environmental changes and ensures evolution.
3. What is binary fission?
Answer: It is a type of asexual reproduction where a single organism divides into two identical individuals.
4. Give one example of an organism that reproduces by budding.
Answer: Hydra or Yeast.
5. What is regeneration?
Answer: The process by which certain organisms can regrow their lost body parts or even form new individuals.
6. Name one plant that reproduces through vegetative propagation.
Answer: Bryophyllum or Potato.
7. What is the function of the placenta?
Answer: It provides oxygen and nutrients to the embryo and removes waste materials.
8. What is meant by fertilisation?
Answer: Fusion of male and female gametes to form a zygote.
9. Differentiate between self-pollination and cross-pollination.
Answer: Self-pollination occurs in the same flower, while cross-pollination occurs between two flowers.
10. Where does fertilisation occur in human beings?
Answer: In the fallopian tube.
11. What are sexually transmitted diseases? Give two examples.
Answer: Diseases transmitted through sexual contact; e.g., AIDS, syphilis.
12. What is menstruation?
Answer: The monthly breakdown and discharge of the uterine lining through the vagina in females.
13. What is the role of seminal vesicles and prostate gland?
Answer: They add fluids that nourish and help transport sperms.
14. Name the male and female sex hormones.
Answer: Male – Testosterone; Female – Estrogen and Progesterone.
15. What is the function of pollen grains?
Answer: They carry male gametes for fertilisation in flowers.
Long Questions Answer
1. Explain the process of reproduction in flowering plants.
Answer: In flowering plants, stamens produce pollen (male gametes) and pistil produces ovules (female gametes). Pollen is transferred to stigma (pollination), followed by fertilisation in the ovary. The zygote forms the embryo; ovule becomes seed, and ovary develops into fruit.
2. Describe the structure and function of the human male reproductive system.
Answer: It includes testes (produce sperms and testosterone), vas deferens (transports sperms), seminal vesicles and prostate gland (add nutrients and fluid), and penis (delivers sperms). Testes are located in the scrotum to maintain lower temperature.
3. Describe the female reproductive system in humans.
Answer: It includes ovaries (produce eggs), fallopian tubes (carry eggs), uterus (site for embryo development), cervix and vagina (birth canal). Fertilisation occurs in fallopian tube, and embryo develops in uterus.
4. What are the different methods of asexual reproduction? Explain with examples.
Answer:
- Fission: Amoeba
- Budding: Hydra, Yeast
- Fragmentation: Spirogyra
- Regeneration: Planaria
- Vegetative propagation: Potato, Bryophyllum
- Spore formation: Rhizopus
5. How does sexual reproduction create variation in a species?
Answer: It combines DNA from two parents, mixing genetic material, resulting in offspring with new combinations of traits, which enhances adaptability and evolution.
6. What are the changes that occur in humans during puberty?
Answer:
- Boys: Facial hair, deep voice, muscular body.
- Girls: Breast development, menstruation, widening of hips.
- Both: Growth of hair in armpits and genital area, emotional and physical maturity.
7. What are the advantages of sexual reproduction over asexual reproduction?
Answer: Sexual reproduction introduces genetic variation, enhances adaptability, and ensures survival of species under changing environments.
8. What is the role of contraception? Mention any three methods.
Answer: Contraception prevents pregnancy.
- Barrier: Condoms
- Hormonal: Oral pills
- Surgical: Vasectomy, Tubectomy
It also helps control population and prevent STDs.
9. Explain the process of fertilisation and embryo development in humans.
Answer: During intercourse, sperm enters vagina, travels to fallopian tube, and fertilises the egg to form a zygote. The zygote divides to form an embryo, which implants in the uterus and develops into a foetus nourished by the placenta.
10. How does reproduction provide stability to populations of species?
Answer: Reproduction ensures continuation of species, maintains genetic stability through DNA copying, and variations help species adapt to environmental changes, balancing extinction and survival.
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