Observe the given diagram and answer the questions that follow :
(i) Give the name and type of reproduction shown in the above diagram.
(ii) Comment on the processes taking place in stage P.
(iii) Name an organism which reproduces by the above mentioned method.
(iv) Name the method that can be used to raise plants that have lost their capacity to produce seeds. List any two advantages of growing plants by such a method.
Generated by claude-sonnet-4-6 · 2026-06-15 06:42 · grounding rag
Model Answer
(i) The diagram shows Multiple Fission, a type of Asexual Reproduction.
(ii) In stage P, the nucleus of the cell (enclosed in a protective cyst) divides repeatedly by mitosis to form many daughter nuclei. Each daughter nucleus then gets surrounded by cytoplasm, eventually forming multiple daughter cells (spores) within the cyst wall. When conditions become favourable, the cyst breaks open and daughter cells are released.
(iii) Plasmodium (malarial parasite) reproduces by multiple fission.
(iv) Tissue Culture is the method used to raise plants that have lost the capacity to produce seeds (e.g., banana, orange, rose, jasmine).
Two advantages:
- Many plants can be grown from a single parent in disease-free conditions.
- All plants produced are genetically similar to the parent, preserving desirable characteristics.
Source: Chapter 7 — Vegetative Propagation (7.2.5), Spore Formation (7.2.6)
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Explanation
- Multiple fission vs. binary fission: In binary fission the nucleus divides once giving 2 daughter cells; in multiple fission the nucleus divides many times first (while enclosed in a cyst), giving many daughter cells simultaneously. Examiners expect this distinction.
- Stage P specifically refers to the repeated nuclear division phase inside the cyst — mention "cyst," "repeated nuclear division," and "daughter cells/spores" for full marks.
- Plasmodium is the textbook example of multiple fission (Exercise Q1 confirms Amoeba → binary fission; Yeast → budding).
- For part (iv), the textbook explicitly names tissue culture for plants like banana, orange, rose, jasmine that have lost seed capacity — use these exact examples if needed. The two advantages must come from the passage (disease-free + genetically similar to parent).