Chapter 1: Reproduction in Organisms – Very Short Answer Type Questions

CBSE Class 12 Biology – Very Short Answer Questions with Answers

Unit I: Reproduction | Chapter 1: Reproduction in Organisms (NCERT Based)

Course & Examination Details

• Course: CBSE Class 12 Biology
• Prescribed By: Central Board of Secondary Education
• Syllabus Reference: NCERT
• Unit: Unit I – Reproduction
• Chapter: Chapter 1 – Reproduction in Organisms
• Exam Relevance: CBSE Class 12 Board Examinations

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CBSE Class 12 Biology Chapter 1 Very Short Answer Questions – Reproduction in Organisms (NCERT)

Section A: Lifespan, Ageing, and Senescence

Q1. What is meant by lifespan in organisms?
Ans: Lifespan is the duration from birth to natural death of an organism, which is genetically determined but influenced by environmental factors.

Q2. How does lifespan vary among organisms?
Ans: Lifespan differs greatly among species, ranging from a few hours in insects to several decades or centuries in higher plants and animals.

Q3. Define ageing.
Ans: Ageing is the gradual decline in physiological efficiency of cells, tissues, and organs with advancing age in an organism.

Q4. What is senescence?
Ans: Senescence is the final phase of ageing marked by progressive deterioration of bodily functions, leading to increased vulnerability and death.

Q5. Is ageing reversible? Give reason.
Ans: No, ageing is irreversible because it involves cumulative cellular damage and reduced regenerative capacity over time.

Section B: Types of Reproduction

Q6. What is reproduction?
Ans: Reproduction is the biological process by which organisms produce new individuals of their own kind, ensuring continuity of species.

Q7. Name the two main types of reproduction.
Ans: The two main types are asexual reproduction and sexual reproduction, based on the number of parents involved.

Q8. Which type of reproduction produces genetic variation?
Ans: Sexual reproduction produces genetic variation due to meiosis and fusion of genetically different gametes.

Q9. Which type of reproduction is faster?
Ans: Asexual reproduction is faster as it involves only one parent and no gamete formation or fertilisation.

Q10. Define clone.
Ans: A clone is a group of genetically identical individuals produced through asexual reproduction from a single parent.

Section C: Asexual Reproduction

Q11. Define asexual reproduction.
Ans: Asexual reproduction is the formation of new individuals from a single parent without gamete formation or fertilisation.

Q12. Name one advantage of asexual reproduction.
Ans: It enables rapid multiplication of organisms and ensures survival in stable and favourable environmental conditions.

Q13. What is binary fission?
Ans: Binary fission is an asexual process in which a unicellular organism divides into two identical daughter cells.

Q14. Name one organism showing binary fission.
Ans: Amoeba reproduces by binary fission where the nucleus and cytoplasm divide to form two individuals.

Q15. What is multiple fission?
Ans: Multiple fission involves repeated nuclear divisions followed by cytoplasmic division, producing many offspring simultaneously.

Q16. Give one example of multiple fission.
Ans: Plasmodium undergoes multiple fission during its life cycle inside the host.

Q17. What is budding?
Ans: Budding is an asexual method in which a small outgrowth develops on the parent body and later detaches as a new individual.

Q18. Name one organism that reproduces by budding.
Ans: Hydra reproduces asexually by budding under favourable conditions.

Q19. Define fragmentation.
Ans: Fragmentation is asexual reproduction in which the parent body breaks into fragments, each growing into a complete organism.

Q20. What is regeneration?
Ans: Regeneration is the ability of an organism to regrow lost body parts, sometimes forming a complete new individual.

Section D: Asexual Reproduction in Plants

Q21. What is vegetative propagation?
Ans: Vegetative propagation is asexual reproduction in plants using vegetative parts like roots, stems, or leaves.

Q22. Name one natural method of vegetative propagation.
Ans: Potato propagates naturally through underground stem tubers bearing eyes.

Q23. Mention one artificial method of vegetative propagation.
Ans: Cutting is an artificial method where a stem piece develops into a new plant.

Q24. State one advantage of vegetative propagation.
Ans: It helps maintain desirable characters and allows rapid multiplication of plants.

Q25. Why are vegetatively propagated plants genetically identical?
Ans: They arise from mitotic divisions of somatic cells without meiosis, resulting in genetically identical offspring.

Section E: Sexual Reproduction

Q26. Define sexual reproduction.
Ans: Sexual reproduction involves formation and fusion of male and female gametes, resulting in genetically varied offspring.

Q27. How many parents are involved in sexual reproduction?
Ans: Usually two parents are involved, each contributing one type of gamete.

Q28. What is the role of meiosis in sexual reproduction?
Ans: Meiosis produces haploid gametes and introduces genetic variation through recombination.

Q29. What are gametes?
Ans: Gametes are haploid reproductive cells that fuse during fertilisation to form a diploid zygote.

Q30. What is meant by isogametes?
Ans: Isogametes are morphologically similar gametes that participate in sexual reproduction.

Section F: Events in Sexual Reproduction

Q31. What is gametogenesis?
Ans: Gametogenesis is the process of formation of male and female gametes by meiosis in sexually reproducing organisms.

Q32. Define fertilisation.
Ans: Fertilisation is the fusion of male and female gametes resulting in the formation of a diploid zygote.

Q33. What is external fertilisation?
Ans: External fertilisation occurs outside the body of the organism, commonly seen in aquatic animals like frogs.

Q34. What is internal fertilisation?
Ans: Internal fertilisation takes place inside the female body, ensuring better survival of the developing embryo.

Q35. What is a zygote?
Ans: A zygote is the first diploid cell formed after fertilisation, giving rise to a new organism.

Section G: Post-Fertilisation Events

Q36. What is embryogenesis?
Ans: Embryogenesis is the process of development of an embryo from the zygote through mitotic divisions and differentiation.

Q37. Name one viviparous organism.
Ans: Humans are viviparous organisms where the embryo develops inside the mother’s body.

Q38. What does oviparous mean?
Ans: Oviparous organisms lay eggs, and embryonic development occurs outside the mother’s body.

Q39. Why is post-fertilisation development important?
Ans: It ensures proper growth, differentiation, and formation of organs in the developing organism.

Q40. Which cell divisions occur during embryogenesis?
Ans: Mitotic divisions occur during embryogenesis to increase cell number and enable growth.

Section H: Reproductive Health (Basic Concepts)

Q41. What is reproductive health?
Ans: Reproductive health refers to the healthy functioning of reproductive organs and the ability to produce viable offspring.

Q42. Name one factor affecting reproductive health.
Ans: Proper nutrition significantly influences reproductive health and successful reproduction.

Q43. Why is reproductive health important for species survival?
Ans: It ensures successful reproduction and healthy offspring, maintaining stable population size.

Q44. How does environment affect reproductive health?
Ans: Unfavourable environmental conditions can impair gamete formation, fertilisation, and development of offspring.

Q45. Is reproductive health limited to humans?
Ans: No, reproductive health applies to all organisms capable of reproduction.

Section I: Conceptual & Application-Based

Q46. Why is sexual reproduction considered evolutionarily important?
Ans: It introduces genetic variation, enabling adaptation to changing environments and driving evolution.

Q47. Why are asexual organisms called clones?
Ans: They are genetically identical to the parent due to absence of meiosis and fertilisation.

Q48. Which reproduction type is common in stable environments?
Ans: Asexual reproduction is common in stable environments due to its speed and efficiency.

Q49. What happens to reproduction during senescence?
Ans: Reproductive capacity declines significantly during senescence due to reduced physiological efficiency.

Q50. State one difference between ageing and senescence.
Ans: Ageing is a gradual lifelong process, whereas senescence is the final stage leading to death.

CBSE Board Exam Note

These Very Short Answer Questions (20–30 words each) are strictly based on NCERT, aligned with CBSE Class 12 Biology examination standards, and ideal for 1-mark and concept-based questions.