CBSE Class 10 Biology How Do Organisms Reproduce Worksheet Set 16

This second printable Class 10 Biology worksheet for How Do Organisms Reproduce has 21 true or false statements, one matching exercise and two quick recall questions, each with the answer, a one-line summary and a teacher's note. The statements test DNA copying, regeneration, pollination, the testes and ovaries, placenta, menstruation, sexual and asexual reproduction and the use of condoms.

True or False

Question 1. Basic event in reproduction is creation of DNA copy.
Answer:
True. Making a copy of the DNA is the basic event in reproduction.
In simple words: DNA copying is the first step of reproduction.

Teacher's Note:
1. The copy is similar, not exactly identical.
2. It is followed by creation of extra cell machinery.

Question 2. Copper-T is a contraceptive device used by women.
Answer:
True. It is placed in the uterus by a doctor and prevents implantation.
In simple words: Copper-T is used by women to prevent pregnancy.

Teacher's Note:
1. It does not protect from STDs.
2. It belongs to the intra-uterine devices (IUCD).

Question 3. At the time of birth, a baby girl has thousands of immature eggs.
Answer:
True. The ovaries of a newborn girl already contain thousands of immature eggs, which start maturing at puberty.
In simple words: The eggs are already present at birth and mature later.

Teacher's Note:
1. One egg is released every month after puberty.
2. Boys start producing sperms at puberty.

Question 4. Sperms mature at a temperature higher than that of human body.
Answer:
False. Sperms are formed at a temperature lower than the body temperature, which the scrotum provides.
In simple words: Sperms need a cooler place than the body.

Teacher's Note:
1. Write the corrected statement.
2. The scrotum keeps the testes about 2 °C cooler.

Question 5. The only function of the testes is to produce sperm.
Answer:
False. The testes also secrete the male hormone testosterone.
In simple words: The testes make sperms and testosterone.

Teacher's Note:
1. Testosterone brings changes at puberty.
2. Name both functions in an exam.

Question 6. Onset of menstruation is termed as menopause.
Answer:
False. The onset (beginning) of menstruation is called menarche. Menopause is the permanent stopping of menstruation.
In simple words: Menarche is the start; menopause is the end.

Teacher's Note:
1. Learn the pair menarche and menopause.
2. Menarche marks the beginning of the reproductive life of a woman.

Question 7. In Spirogyra, asexual reproduction takes place by fragmentation.
Answer:
True. A mature filament breaks into pieces and each piece grows into a new filament.
In simple words: Spirogyra multiplies by breaking into pieces.

Teacher's Note:
1. Planaria uses regeneration, Hydra uses budding.
2. Fragmentation is asexual.

Question 8. Vegetative propagation by leaves occurs in sweet potato.
Answer:
False. In sweet potato, vegetative propagation takes place by roots. Bryophyllum is propagated by leaves.
In simple words: Sweet potato uses roots; Bryophyllum uses leaves.

Teacher's Note:
1. Match the plant with its part: potato (stem), sweet potato (root), Bryophyllum (leaf).
2. Write the corrected statement.

Question 9. Transfer of male gametes to the stigma of flower is called pollination.
Answer:
True. Pollination is the transfer of pollen grains, which carry the male gametes, from the anther to the stigma.
In simple words: Moving pollen from anther to stigma is pollination.

Teacher's Note:
1. Fertilisation is the fusion of gametes, not the transfer of pollen.
2. Pollination comes first.

Question 10. In mammals including man, fertilization takes place externally.
Answer:
False. In mammals, including human beings, fertilisation is internal; it takes place inside the female body, in the fallopian tube.
In simple words: Fertilisation happens inside the body in humans.

Teacher's Note:
1. External fertilisation occurs in fish and frogs.
2. Give the site: fallopian tube.

Question 11. In human-beings, male can produce sperms upto the age of 45-50 years.
Answer:
False. A man can produce sperms throughout his life after puberty. It is in women that the release of eggs stops at about 45 to 50 years (menopause).
In simple words: Men keep making sperms; women stop ovulating at menopause.

Teacher's Note:
1. Compare with menopause in women.
2. Give the corrected statement.

Question 12. In fission, many bacteria and protozoa simply divide into two or more daughter cells.
Answer:
True. Fission is the splitting of a single-celled organism into two (binary) or many (multiple) daughter cells.
In simple words: Single-celled organisms multiply by splitting.

Teacher's Note:
1. Binary fission gives two cells.
2. Multiple fission gives many cells.

Question 13. Plants that produce asexually do not produce flowers.
Answer:
False. Many plants that are propagated vegetatively, for example rose and jasmine, still bear flowers and reproduce sexually through seeds also.
In simple words: Asexually propagated plants can still flower.

Teacher's Note:
1. Vegetative propagation does not prevent flowering.
2. Plants raised this way flower earlier.

Question 14. Placenta is the name of a vital connection between mother and embryo.
Answer:
True. The placenta connects the embryo to the uterine wall and supplies nutrition and oxygen and removes wastes.
In simple words: The placenta links the baby and the mother.

Teacher's Note:
1. Name the umbilical cord as the link to the foetus.
2. The placenta is embedded in the uterine wall.

Question 15. The male germ cell produced by pollen grain contains half the amount of DNA as compared to the other body cells of the plant.
Answer:
True. Gametes are formed by meiosis, so they carry half the DNA and half the chromosomes of the body cells.
In simple words: Gametes carry half the DNA of body cells.

Teacher's Note:
1. Fertilisation restores the full amount.
2. This keeps DNA from doubling every generation.

Question 16. Vegetative propagation produces plants that are genetically similar to the parent plant.
Answer:
True. Only one parent is involved and no gametes fuse, so the plants are genetically similar (clones) to the parent.
In simple words: Plants from cuttings are copies of the parent.

Teacher's Note:
1. This is both an advantage and a disadvantage.
2. Variation is absent.

Question 17. Regeneration is the same as reproduction.
Answer:
False. Regeneration is the ability to regrow lost body parts and most organisms cannot reproduce by being cut up. Only in a few animals such as Planaria does regeneration give new individuals.
In simple words: Regeneration repairs the body; reproduction makes new individuals.

Teacher's Note:
1. Most organisms do not depend on being cut up to reproduce.
2. Planaria is a special case.

Question 18. Before cell division, copying of DNA is not essential.
Answer:
False. Before a cell divides, its DNA is copied so that each daughter cell receives a copy.
In simple words: Each new cell needs its own copy of the DNA.

Teacher's Note:
1. Use the words DNA replication.
2. Without a copy a daughter cell would lack DNA.

Question 19. Sexually transmitted diseases can be prevented by using condoms.
Answer:
True. A condom is a barrier that prevents the exchange of body fluids, so it protects against many STDs, including HIV.
In simple words: A condom helps prevent STDs.

Teacher's Note:
1. Condoms also prevent pregnancy.
2. Copper-T and oral pills do not protect against STDs.

Question 20. Sexual reproduction does not lead to variation in a population.
Answer:
False. Sexual reproduction mixes the DNA of two parents, so the offspring show variations.
In simple words: Mixing the DNA of two parents gives variation.

Teacher's Note:
1. Variation is the basis of evolution.
2. Asexual reproduction gives little variation.

Question 21. The ovary of a flower grows into a fruit.
Answer:
True. After fertilisation the ovary grows and ripens into the fruit, and the ovules become seeds.
In simple words: Ovary becomes fruit and ovule becomes seed.

Teacher's Note:
1. Say what happens to the ovule too.
2. Petals and sepals fall off.

Match the Following

Question 22. Match the following. Column A: (A) Animals which give birth to young one (B) Animal which produces bud (C) An animal which shows regeneration (D) Provides nutrition to the developing embryo from the mother (E) The pollen transferred from one flower to another flower of other plant (F) The process in which embryo develops into seedling (G) Fertilised egg in humans gets implanted in (H) When egg in humans is not fertilised, what happens? Column B: (p) Hydra (q) Planaria (r) Placenta (s) Cross-pollination (t) Germination (u) Viviparous (v) Menstruation (w) Uterus.
Answer:
(A) matches (u) Viviparous.
(B) matches (p) Hydra.
(C) matches (q) Planaria.
(D) matches (r) Placenta.
(E) matches (s) Cross-pollination.
(F) matches (t) Germination.
(G) matches (w) Uterus.
(H) matches (v) Menstruation.
In simple words: A to u, B to p, C to q, D to r, E to s, F to t, G to w, H to v.

Teacher's Note:
1. Match the easy pairs first and cross them out.
2. Each item of Column B is used once.

Quick Recall Questions

Question 23. Write the names of any three methods of artificial vegetative reproduction.
Answer:
Cutting, layering and grafting (tissue culture is another method).
In simple words: Cutting, layering and grafting are the common artificial methods.

Teacher's Note:
1. Give a plant example for each.
2. Rose is grown by cutting.

Question 24. Write the full form of: (i) STD (ii) AIDS (iii) IUCD.
Answer:
(i) STD: Sexually Transmitted Disease.
(ii) AIDS: Acquired Immuno Deficiency Syndrome.
(iii) IUCD: Intra Uterine Contraceptive Device.
In simple words: STD, AIDS and IUCD are short forms used in reproductive health.

Teacher's Note:
1. Learn these three full forms.
2. HIV stands for Human Immunodeficiency Virus.