Class 10 Science: How do Organisms Reproduce? important questions

How do Organisms Reproduce? is a chapter of Class 10 Science for the Andhra Pradesh State Board. These 12 questions are marked Very Important, Important or Practice, and each answer has been checked by our team. Use them to revise, not as a prediction of what will come in the exam.

1. Very Important · 8 marks

   1. What are the different modes of asexual reproduction in plants and simple organisms?

   1) Fission: a single cell divides into two (binary fission, e.g. Amoeba) or many (multiple fission, e.g. Plasmodium). 2) Budding: a small outgrowth forms and grows into a new individual (e.g. yeast, Hydra). 3) Fragmentation: the body breaks into pieces and each piece grows into a new organism (e.g. Spirogyra). 4) Regeneration: a lost part grows back, or a part grows into a whole organism (e.g. Planaria). 5) Spore formation: spores in sporangia spread and grow into new individuals (e.g. Rhizopus). 6) Vegetative propagation: new plants grow from roots, stems or leaves (e.g. Bryophyllum leaves, potato tubers, rose cuttings, grafting in mango). 7) Tissue culture: new plants are grown from a few cells in a nutrient medium (e.g. orchids, banana).

2. Practice · 1 marks

   2. Write a slogan to stop female foeticide.

   "Save the girl child: a daughter is a blessing, not a burden."

3. Important · 4 marks

   3. Describe a labelled diagram of fertilisation in a flower.

   Show a pistil with the stigma at the top, the style, and the ovary at the base containing an ovule. A pollen grain lands on the stigma and grows a pollen tube down through the style into the ovary. The tube enters the ovule, and the male germ cell fuses with the female germ cell (egg). Labels: pollen grain, stigma, pollen tube, style, ovary, ovule, female germ cell. The fused cell, the zygote, grows into the embryo; the ovule becomes the seed and the ovary becomes the fruit.

4. Important · 4 marks

   4. Give your friend some suggestions to raise awareness about reproductive health.

   1) Maintain personal hygiene. 2) Learn about the changes during puberty from parents, teachers or doctors, not from rumours. 3) Understand sexually transmitted diseases, such as HIV/AIDS, and how to prevent them. 4) Know that early marriage and early pregnancy harm health. 5) Have regular medical check-ups and seek help when needed. 6) Respect girls and boys equally and oppose female foeticide.

5. Important · 2 marks

   5. Vegetative propagation: by leaf, e.g. Bryophyllum; by root, e.g. sweet potato and dahlia. a) Give an example of a plant that propagates vegetatively by its root. b) Which part of Bryophyllum is involved in vegetative propagation?

   a) Sweet potato (or dahlia). b) The leaf: buds form in the notches along the leaf margin, and they grow into new plants.

6. Important · 2 marks

   6. Write two slogans to raise awareness about AIDS.

   1) "Awareness is the best protection: know about AIDS, stop AIDS." 2) "Safe choices today, a healthy life tomorrow."

7. Important · 4 marks

   7. Describe a neat labelled diagram of the human female reproductive system.

   Show the two ovaries, one on each side; an oviduct (fallopian tube) running from each ovary to the uterus; the uterus, a muscular bag in the middle; the cervix, the narrow lower end of the uterus; and the vagina, opening to the outside. Labels: ovary, oviduct (fallopian tube), uterus, cervix, vagina.

8. Very Important · 8 marks

   8. Write an activity to observe asexual reproduction in yeast.

   1) Dissolve about 10 g of sugar in 100 mL of water. 2) Add a pinch of yeast granules and keep the solution in a warm place for 1–2 hours. 3) Put a drop of it on a slide, cover it with a coverslip and observe under a microscope. Observation: small outgrowths (buds) form on the yeast cells; some buds have their own buds, forming chains. Conclusion: yeast reproduces asexually by budding.

9. Practice · 1 marks

   9. Expand HIV.

   Human Immunodeficiency Virus: the virus that causes AIDS.

10. Practice · 1 marks

    10. Radha added yeast to sugar solution, covered it with a glass plate and kept it in a refrigerator. After a few hours she saw no reproduction. What should she change? A) Heat the sugar solution before observing. B) Heat the solution and keep it in a refrigerator. C) Keep the container in a warm place. D) Keep the container open.

    C) Keep it in a warm place. Yeast grows and buds well in warmth; the cold of a refrigerator slows its activity.

11. Important · 4 marks

    11. Describe a diagram of a flower with its parts labelled.

    Draw a flower in section on its stalk. Outer whorl: green sepals. Next: coloured petals. Stamens (male part): each has a thin filament with an anther at the tip, which holds pollen grains. Pistil (female part) in the centre: the stigma at the top, the style (a tube) below it, and the swollen ovary at the base containing ovules. Labels: sepal, petal, stamen (anther, filament), pistil (stigma, style, ovary), ovule.

12. Very Important · 8 marks

    12. Describe the procedure to observe spores of Rhizopus (bread mould). Mention the precautions.

    1) Moisten a slice of bread and keep it in a cool, moist, dark place for 3–4 days. 2) A white cottony mass (mould) grows on it, which later shows black dots. 3) With a needle, place a small bit of the mould on a slide in a drop of water, cover it with a coverslip and observe under a microscope. Observation: thread-like hyphae, and round sporangia at the tips of some threads, containing many spores. Precautions: wear gloves and a mask; do not inhale the spores; do not touch your face; wash your hands after the activity; dispose of the mouldy bread safely.