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🧬 UNIT – 7: HOW DO ORGANISMS REPRODUCE?(questions)

🧬 UNIT – 7: HOW DO ORGANISMS REPRODUCE?

Learning Points

  • Reproduction and importance of variation

  • Types of asexual reproduction: fission, budding, fragmentation, regeneration, spore formation, vegetative reproduction

  • Sexual reproduction in flowering plants

  • Structure and functions of male and female reproductive systems

  • What happens when egg is fertilized and not fertilized

  • Reproductive health and contraception

  • Sexually transmitted diseases

I. Multiple Choice Questions (1 Mark each)

  1. The group of organisms that reproduce through fission only is:
    A. Amoeba, Hydra, Spirogyra
    B. Leishmania, Amoeba, Yeast
    C. Amoeba, Plasmodium, Planaria
    D. Plasmodium, Amoeba, Leishmania

  2. In the given figure of cotyledon, the parts labelled A and B respectively are:
    A. Fruit, shoot
    B. Primary shoot, primary root
    C. Secondary root, primary shoot
    D. Bud, leaf

  3. The type of reproduction found in Spirogyra is:
    A. Budding
    B. Fragmentation
    C. Vegetative reproduction
    D. Spore formation

  4. The common passage for both sperm and urine in the male reproductive system is:
    A. Urethra
    B. Ureter
    C. Vas deferens
    D. Urinary bladder

  5. The correct sequence in sexual reproduction in flowers is:
    A. Pollination → Fertilization → Seed → Embryo
    B. Seed → Embryo → Fertilization → Pollination
    C. Embryo → Seed → Pollination → Fertilization
    D. Pollination → Fertilization → Embryo → Seed

  6. In human females, the egg is carried from ovary to uterus through:
    A. Cervix
    B. Fallopian tube
    C. Placenta
    D. Vagina

  7. Common bacterial infection spread through sexual contact:
    A. Gonorrhoea
    B. AIDS
    C. Hepatitis-B
    D. Warts

  8. In humans, sexually transmitted viral infection is:
    A. AIDS
    B. Syphilis
    C. Tuberculosis
    D. Gonorrhoea

  9. Parts that develop into fruit and seed respectively:
    A. Stamen and ovary
    B. Ovule and ovary
    C. Ovary and ovule
    D. Stamen and ovule

  10. In humans, testes are located in scrotum to:
    A. Protect from shocks
    B. Increase sperm production
    C. Maintain testosterone secretion
    D. Maintain required temperature for sperm production

  11. The process shown in diagram represents:
    A. Fragmentation
    B. Regeneration
    C. Vegetative propagation
    D. Binary fission

  12. Correct order of binary fission in Leishmania:
    A. II, III, IV
    B. I, III, IV, II
    C. IV, I, III, II
    D. III, I, II, IV

  13. AIDS : Virus :: Warts : ________
    A. Bacteria
    B. Fungus
    C. Protozoa
    D. Virus

  14. Part of flower developing into fruit and seed respectively:
    A. Ovary and plumule
    B. Plumule and radicle
    C. Ovary and radicle
    D. Ovary and ovule

  15. Reproduction in Planaria occurs by:
    A. Binary fission
    B. Regeneration
    C. Budding
    D. Fragmentation

  16. The embryo gets nutrition from the mother’s blood through:
    A. Fallopian tube
    B. Ovary
    C. Uterus
    D. Placenta

  17. Fertilization of the egg is possible only in which structure?
    A. Both figures
    B. Only Figure B
    C. Only Figure A
    D. None of these

II. One Mark Questions

  1. Write two examples for organisms that reproduce by binary fission.

  2. Is self-pollination possible in flowers having only stamens?

  3. What functions do testicles perform in humans?

  4. Sexual reproduction causes more variation — why?

  5. Among flowers A and B, which undergoes self-pollination?

  6. What is sexual reproduction?

  7. Name two viral infections transmitted through unprotected sexual contact.

  8. Does Copper-T prevent sexually transmitted diseases?

  9. “Sex determination at birth should not be done.” Justify.

III. Two Mark Questions

  1. Explain the cause of thread-like structures seen on a tomato kept for four days.

  2. Why does menstruation occur?

  3. How does uterus prepare to receive fertilized egg? What happens if not fertilized?

  4. How does budding in Hydra differ from Bryophyllum?

  5. How do germ cells receive half the amount of DNA? Why is it necessary?

  6. Draw the diagram showing germination of pollen on stigma.

  7. Explain how fertilized egg develops into an embryo.

  8. How can pregnancy be prevented surgically?

  9. Is surgical contraception better than physical contraception?

  10. How is pollination different from fertilization?

IV. Three Mark Questions

  1. Explain how testis position, testosterone, and prostate gland secretion support male fertility.

  2. What is pollination? What changes occur in the flower after pollination?

  3. (a) How does sexual reproduction ensure variation?
      (b) State two functions of placenta.

  4. Compare reproduction in Hydra and Planaria.

  5. Explain the process of embryo development and placental nutrition.

  6. Explain the importance of sexual reproduction in species survival.

  7. Differentiate between fragmentation and regeneration with examples.

  8. Explain self and cross pollination.

  9. Describe what happens after fertilization in flowering plants.

  10. Write any three advantages of spore formation.

  11. Explain how DNA is copied during cell division and its importance.

  12. Describe structure and function of placenta.

V. Four Mark Questions

  1. Explain functions of testis, scrotum, urethra, vas deferens, prostate gland and penis.

  2. “Reaching sexual maturity is necessary for reproduction in humans.” Justify.

  3. Explain structure and function of female reproductive system.

  4. Justify: “Placenta plays an important role in foetal development.”

  5. Mention advantages of vegetative reproduction and its usefulness in agriculture.


🧬 UNIT – 7 : HOW DO ORGANISMS REPRODUCE – KEY ANSWERS

I. Multiple Choice Questions (1 mark each)

No Correct Answer Explanation
1 ✅ D. Plasmodium, Amoeba, Leishmania All reproduce by fission
2 ✅ B. Primary shoot, primary root Cotyledon parts
3 ✅ B. Fragmentation Spirogyra reproduces by fragmentation
4 ✅ A. Urethra Common passage for urine and sperm
5 ✅ D. Pollination → Fertilization → Embryo → Seed Correct reproductive sequence
6 ✅ B. Fallopian tube Site of fertilization, connects ovary to uterus
7 ✅ A. Gonorrhoea Bacterial infection
8 ✅ A. AIDS Viral infection (HIV)
9 ✅ C. Ovary and ovule Ovary → fruit; Ovule → seed
10 ✅ D. Maintain temperature for sperm formation Scrotum keeps testis cooler
11 ✅ D. Binary fission Equal division of parent cell
12 ✅ C. IV, I, III, II Order of fission in Leishmania
13 ✅ D. Virus Both AIDS and warts caused by viruses
14 ✅ D. Ovary and ovule Form fruit and seed
15 ✅ B. Regeneration Planaria regenerates from body fragments
16 ✅ D. Placenta Connects embryo to mother for nourishment
17 ✅ C. Only Figure A Fertilization occurs in fallopian tube

II. One Mark Answers

  1. Examples: Amoeba, Leishmania.

  2. No, self-pollination is not possible in unisexual flowers having only stamens.

  3. Functions of testicles: Produce sperms and secrete testosterone.

  4. Variation: Sexual reproduction combines DNA from both parents → diversity.

  5. Self-pollination: Occurs in flower A (bisexual).

  6. Sexual reproduction: Process involving fusion of male and female gametes.

  7. Viral infections: AIDS (HIV), Warts (HPV).

  8. No, Copper-T prevents pregnancy but not STDs.

  9. Justification: Sex determination is natural and misuse leads to female foeticide.

III. Two Mark Answers

  1. Cause: Fungal spores germinate → hyphae form on tomato surface.

  2. Menstruation: Occurs due to breakdown of uterine lining when fertilization fails.

  3. Preparation: Uterine wall thickens → ready for implantation;
    If unfertilized → lining sheds → menstruation.

  4. Difference:
    Hydra – Budding (new organism forms as outgrowth).
    Bryophyllum – Vegetative reproduction via leaf buds.

  5. Half DNA: During meiosis; ensures restoration of chromosome number after fertilization.

  6. Diagram: Germination of pollen grain → pollen tube grows through style to ovule.

  7. Development: Zygote divides repeatedly → forms embryo → attaches to uterine wall.

  8. Surgical methods:
    Males – Vasectomy; Females – Tubectomy.

  9. Yes, surgical methods more reliable and long-term than physical barriers.

  10. Difference:

Pollination Fertilization
Transfer of pollen Fusion of gametes
Occurs in flower Occurs in ovary

IV. Three Mark Answers

  1. Testis: Produces sperm and testosterone;
    Scrotum: Regulates temperature;
    Prostate gland: Secretes fluid for sperm mobility.

  2. Pollination: Transfer of pollen;
    After pollination: Ovary → fruit, ovule → seed, petals dry up.

  3. (a) Variation arises due to DNA recombination.
    (b) Placenta – provides nutrients and oxygen, removes waste.

  4. Hydra: Budding; Planaria: Regeneration.

  5. Embryo development: Fertilized egg divides → embryo → attaches via placenta → nutrient exchange.

  6. Importance: Maintains species variation, adaptability, and evolution.

  7. Fragmentation: Each piece grows into organism (Spirogyra).
    Regeneration: Lost parts regrow (Planaria).

  8. Self-pollination: Same flower.
    Cross-pollination: Between two flowers/plants.

  9. After fertilization:
    Zygote → Embryo → Ovule → Seed → Ovary → Fruit.

  10. Advantages of spore formation:

  • Large number of offspring

  • Resistant to harsh conditions

  • Easy dispersal.

  1. DNA copying: Occurs during cell division → ensures heredity with small variations.

  2. Placenta: Connects foetus to mother, transfers nutrients, gases, and wastes.

V. Four Mark Answers

  1. Functions (Male reproductive system):

  • Testis: Produces sperm & hormones

  • Scrotum: Maintains temperature

  • Vas deferens: Transports sperm

  • Urethra: Common passage

  • Prostate gland: Secretes seminal fluid

  • Penis: Transfers sperms

  1. Justification:
    Sexual maturity → reproductive organs functional → gametes formed → successful fertilization.

  2. Female reproductive system:
    Ovaries → Produce ovum;
    Fallopian tubes → Site of fertilization;
    Uterus → Foetal development;
    Vagina → Birth canal.

  3. Placenta importance:

  • Transfers nutrients & O₂

  • Removes wastes

  • Produces hormones

  • Protects embryo

  1. Advantages of vegetative reproduction:

  • Quick and identical offspring

  • Bypasses pollination

  • Useful for high-yield crop propagation


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