CBSE Class 10 Science Asexual Reproduction Worksheet Set 05

Answer: Asexual reproduction involves a single parent and no fusion of gametes. The offspring are therefore genetically and morphologically identical to the parent.

Teacher's Note:
1. Clones share the same DNA copy as the parent.
2. Small variations arise only from minor copying errors.

Answer: A unicellular organism reproduces by dividing into two, so the parent body continues as the daughter cells and there is no dead parent. A multicellular organism has specialised cells and organs that age, and the body as a whole dies.

Teacher's Note:
1. Immortal here means no natural death by ageing.
2. Unicellular organisms can still be killed by harmful conditions.

Answer: Banana is propagated vegetatively. New plantlets (suckers) arise from buds on the underground stem, and they are separated and planted as new plants.

Teacher's Note:
1. Vegetative propagation uses roots, stems or leaves.
2. It keeps the good qualities of the parent plant.

Answer: (b) (i), (iii) and (iv). Asexual: banana (vegetative propagation), yeast (budding) and Amoeba (fission); a dog reproduces sexually.

Teacher's Note:
1. Dogs reproduce sexually.
2. Yeast, Amoeba and banana can all form new individuals from a single parent.

Answer: (b) hyphae. Hyphae are the thread-like structures that bear sporangia in Rhizopus.

Teacher's Note:
1. Hyphae are the thread-like body parts of fungi.
2. Sporangia produce the spores that spread the fungus.

Answer: An individual survives through nutrition and respiration, and reproduction does not help it survive. Reproduction passes on DNA to the next generation, which keeps the population of the species stable over time.

Teacher's Note:
1. Individuals die but the species continues through its offspring.
2. Reproduction also creates the variation that helps a species adapt.

Answer: Yes. The cell divides to form two new individuals, so the number of organisms increases.

Teacher's Note:
1. Reproduction means creating new individuals like the parent.
2. Amoeba is a good example.

Answer: Sugar gives yeast the energy needed to multiply, while water has no food. Bread mould needs moisture as well as food, and a dry slice has food but no moisture.

Teacher's Note:
1. Living things need both energy and suitable conditions to grow.
2. Spores stay dormant until conditions suit them.

Answer: In binary fission the parent cell divides into two equal daughter cells (example: Amoeba). In multiple fission the nucleus divides many times and the cell then splits into many daughter cells at once (example: Plasmodium).

Teacher's Note:
1. Both are forms of asexual reproduction in unicellular organisms.
2. Multiple fission takes place under unfavourable conditions in many protozoa.

Answer: In fragmentation a simple multicellular organism breaks into pieces and each piece grows into a complete organism (example: Spirogyra). Regeneration is the ability of specialised cells to grow back lost body parts, and in Planaria or Hydra a cut piece can form a complete organism.

Teacher's Note:
1. Fragmentation is a way of reproducing.
2. Regeneration can repair the body or make a new organism.

Answer: Regeneration is the ability of an organism to form a complete new individual from a cut or broken body part. Planaria and Hydra can do this.

Teacher's Note:
1. Specialised cells dedicated to regrowth are involved.
2. Regeneration is not the same as reproduction in all animals.

Answer: Complex organisms have cells organised into tissues, organs and organ systems. Such a high degree of organisation cannot be rebuilt from a cut body part.

Teacher's Note:
1. Specialised cells do not easily turn back into other types.
2. Simple organisms have fewer cell types.

Answer: Tissue culture is the growing of new plants from a small piece of plant tissue placed in a nutrient medium under sterile conditions. Orchids and chrysanthemum are examples.

Teacher's Note:
1. Plants from tissue culture are identical to the parent.
2. Many plants can be produced in a short time.

Answer: (a) X is yeast and Y is Hydra.
(b) Fermentation.
(c) Hydra is multicellular and yeast is unicellular.

Teacher's Note:
1. Yeast belongs to the fungi.
2. Hydra has tentacles and can also regenerate.

Answer: (a) Bryophyllum.
(b) Buds.
(c) Begonia.

Teacher's Note:
1. Leaf buds fall to the soil and grow into plantlets.
2. This is a natural method of vegetative propagation.

Answer: (a) Stem tuber.
(b) Potato.
(c) Eyes (buds).
(d) No, a cut piece with at least one eye will grow into a new plant.

Teacher's Note:
1. Eyes contain buds that sprout under suitable conditions.
2. This is vegetative propagation.

Answer: (a) A is Leishmania, B is Plasmodium, C is Amoeba, D is Paramecium.
(b) Female Anopheles mosquito.
(c) A: binary fission. B: multiple fission.

Teacher's Note:
1. Leishmania has a whip-like flagellum.
2. Amoeba and Paramecium live in pond water.