CBSE Class 10 Biology How Do Organisms Reproduce Worksheet Set 15

This printable Class 10 Biology worksheet for How Do Organisms Reproduce has 22 short questions: 12 fill in the blanks and 10 very short questions, each with the answer, a one-line summary and a teacher's note. It revises hermaphrodites, budding, vegetative propagation, grafting, tissue culture, meiosis, the zygote, the female reproductive system, STDs, the testes, flower whorls and the agents of pollination.

Fill in the Blanks

Question 1. In many invertebrate organisms, both sexes are found in the same individual. This is called ..................
Answer:
Hermaphroditism (bisexuality). Earthworm and leech are examples.
In simple words: Hermaphrodites carry both male and female organs.

Teacher's Note:
1. Name an example such as earthworm.
2. Hermaphrodite is the organism; hermaphroditism is the condition.

Question 2. Budding is a common method of asexual reproduction in yeast and ..................
Answer:
Hydra.
In simple words: Yeast and Hydra both reproduce by budding.

Teacher's Note:
1. Remember: Hydra and yeast are the two budding examples.
2. Hydra also reproduces by regeneration.

Question 3. In ..............., vegetative propagation occurs by leaves.
Answer:
Bryophyllum. Buds in the notches of its leaves grow into new plants.
In simple words: Bryophyllum grows new plants from its leaf buds.

Teacher's Note:
1. Potato uses stem, sweet potato uses roots.
2. Bryophyllum is the leaf example.

Question 4. Surgically when fallopian tube is removed or ligated, it is called ...............
Answer:
Tubectomy. (In males the corresponding operation on the vas deferens is vasectomy.)
In simple words: Tubectomy blocks the oviducts of a woman.

Teacher's Note:
1. Do not mix up tubectomy and vasectomy.
2. Both are permanent surgical methods.

Question 5. An egg cell of a plant is contained in an ............ present in an ovary.
Answer:
Ovule. After fertilisation the ovule becomes the seed.
In simple words: The ovule is the chamber that holds the egg in the ovary.

Teacher's Note:
1. Ovary becomes fruit, ovule becomes seed.
2. The ovary may contain one or more ovules.

Question 6. Transfer of pollen from one flower to stigma of another flower of same species is termed ........................
Answer:
Cross-pollination.
In simple words: Pollen going to another plant's flower is cross-pollination.

Teacher's Note:
1. Self-pollination happens within one flower or one plant.
2. Wind, water and animals carry pollen.

Question 7. Ovaries are also responsible for the production of hormone called ........................
Answer:
Oestrogen (and progesterone).
In simple words: The ovaries make oestrogen and progesterone along with eggs.

Teacher's Note:
1. Testes make testosterone.
2. Oestrogen brings changes at puberty in girls.

Question 8. Plants raised by vegetative propagation bear early ............ and ....................
Answer:
Flowers and fruits.
In simple words: Plants grown from cuttings flower and fruit sooner than plants grown from seeds.

Teacher's Note:
1. This is one advantage of vegetative propagation.
2. Another advantage: seedless plants can be grown.

Question 9. Future shoot hidden in a seed is called ..................
Answer:
Plumule. (The future root is the radicle.)
In simple words: Plumule becomes the shoot; radicle becomes the root.

Teacher's Note:
1. Plumule is the shoot; radicle is the root.
2. Both are parts of the embryo.

Question 10. The gametes are formed in most of the multicellular organisms by a process of cell division called ...............
Answer:
Meiosis (reduction division), which halves the number of chromosomes.
In simple words: Meiosis makes gametes with half the chromosomes.

Teacher's Note:
1. Meiosis keeps the chromosome number constant over generations.
2. The zygote restores the full number.

Question 11. The two parts tied together during grafting are called ........ and ............
Answer:
Stock (the rooted plant) and scion (the cut piece of another plant without roots).
In simple words: In grafting a scion is attached to a rooted stock.

Teacher's Note:
1. Stock gives roots; scion gives the shoot.
2. Grafting combines the good qualities of two plants.

Question 12. Simply break up into smaller pieces upon maturation is found in ..................
Answer:
Spirogyra. This is fragmentation.
In simple words: Spirogyra breaks into pieces and each piece grows.

Teacher's Note:
1. Fragmentation is seen in multicellular filamentous organisms.
2. It is an asexual method.

Very Short Answer Questions

Question 13. What is tissue culture?
Answer:
Tissue culture is a technique in which new plants are grown from cells or tissues taken from the growing tip of a plant and placed in an artificial nutrient medium. The cells form a mass called callus, which is shifted to a medium with hormones for growth and differentiation, and the small plants are then planted in soil.
In simple words: Plants are grown from a few cells in a nutrient medium.

Teacher's Note:
1. Mention the growing tip and callus.
2. It is used for ornamental plants.

Question 14. How the zygote is formed?
Answer:
The zygote is formed when the male gamete (sperm) fuses with the female gamete (egg or ovum) in fertilisation. It is a single, diploid cell.
In simple words: Sperm plus egg make the zygote.

Teacher's Note:
1. Name the process: fertilisation.
2. The zygote divides to form the embryo.

Question 15. Name the parts of female reproductive system.
Answer:
The parts are the ovaries, oviducts (fallopian tubes), uterus, cervix and vagina.
In simple words: Ovary, oviduct, uterus, cervix and vagina make the female reproductive system.

Teacher's Note:
1. Learn them in order of the path of the egg.
2. Ovaries are the primary sex organs.

Question 16. Name any two sexually transmitted diseases.
Answer:
Gonorrhoea and syphilis (bacterial); AIDS and genital warts (viral) are other examples.
In simple words: Gonorrhoea and syphilis are two common STDs.

Teacher's Note:
1. Know two bacterial and two viral examples.
2. STDs spread through sexual contact.

Question 17. What is caused if the testes in human males fail to descend into the scrotal sacs?
Answer:
The production of sperms by the testes needs a temperature slightly lower than the normal body temperature, and the scrotal sacs provide it. If the testes do not descend into the scrotal sacs, enough sperms cannot be formed.
In simple words: Testes inside the body are too warm to make enough sperms.

Teacher's Note:
1. Link the answer to the lower temperature of the scrotum.
2. This can cause infertility.

Question 18. What is the function of sepals?
Answer:
The sepals protect the flower in the bud condition and support the other floral parts in the open flower.
In simple words: Sepals are the green guards of the flower bud.

Teacher's Note:
1. Sepals form the outermost whorl, the calyx.
2. Petals attract insects.

Question 19. Name the two animals in which asexual reproduction takes place.
Answer:
Amoeba (binary fission) and Hydra (budding). Planaria (regeneration) is another example.
In simple words: Amoeba and Hydra reproduce without gametes.

Teacher's Note:
1. Name the mode with each animal.
2. Asexual means one parent, no gametes.

Question 20. Give the names of different whorls of a flower.
Answer:
Accessory whorls: calyx (sepals) and corolla (petals). Essential (reproductive) whorls: androecium (stamens, the male part) and gynoecium (carpels or pistil, the female part).
In simple words: A flower has four whorls: calyx, corolla, androecium and gynoecium.

Teacher's Note:
1. Name them from the outside to the inside.
2. Stamens and carpels are the reproductive parts.

Question 21. Name any two such animals in which external fertilization takes place.
Answer:
Frog and fishes. Their gametes are released into water, where the male and female gametes fuse outside the body.
In simple words: Frogs and fishes shed gametes in water, so fertilisation is outside the body.

Teacher's Note:
1. External fertilisation happens in water.
2. Mammals have internal fertilisation.

Question 22. Name the different agents of pollination.
Answer:
The agents of pollination are wind, water, insects and other animals (such as birds).
In simple words: Wind, water and animals carry pollen.

Teacher's Note:
1. Insect pollinated flowers are coloured and scented.
2. Wind pollinated flowers make a lot of pollen.