(a) Write one function each of the following, in a seed:

(i) Seed coat (ii) Cotyledon (iii) Radicle (iv) Plumule

OR

(b) Write the main steps to culture yeast in the laboratory.

Q: (a) Write one function each of the following, in a seed: (i) Seed coat (ii) Cotyledon (iii) Radicle (iv) Plumule OR (b) Write the main steps to culture yeast in the laboratory.

**(a) Functions of seed parts:** | Part | Function | |---|---| | (i) Seed coat | A tough, protective outer covering that protects the embryo inside the seed from injury and desiccation until conditions favour germination. | | (ii) Cotyledon | Stores the food reserves that nourish the developing embryo/seedling during germination, before it can photosynthesise on its own. | | (iii) Radicle | The embryonic root; it grows downward on germination to form the root system, anchoring the seedling and absorbing water and minerals. | | (iv) Plumule | The embryonic shoot; it grows upward on germination to form the stem and leaves of the new plant. | **OR** **(b) Main steps to culture yeast in the laboratory** (based on Activity 7.1): 1. Dissolve about 10 g of sugar in 100 mL of water to prepare a sugar solution (this provides food for the yeast). 2. Take 20 mL of this sugar solution in a test tube and add a pinch of yeast granules to it. 3. Plug the mouth of the test tube with cotton (to allow air exchange while keeping contaminants out) and place it in a warm location. 4. After 1–2 hours, place a small drop of the yeast culture on a slide, cover it with a coverslip, and observe under a microscope — budding yeast cells (small outgrowths separating from the parent cell) can be seen, showing that the yeast has grown and reproduced by budding.

How do Organisms Reproduce?

Sexual Reproduction in Flowering Plants / Fission — Yeast Culture (internal choice)

Official Answer

(a) Functions of seed parts:

Part	Function
(i) Seed coat	A tough, protective outer covering that protects the embryo inside the seed from injury and desiccation until conditions favour germination.
(ii) Cotyledon	Stores the food reserves that nourish the developing embryo/seedling during germination, before it can photosynthesise on its own.
(iii) Radicle	The embryonic root; it grows downward on germination to form the root system, anchoring the seedling and absorbing water and minerals.
(iv) Plumule	The embryonic shoot; it grows upward on germination to form the stem and leaves of the new plant.

(b) Main steps to culture yeast in the laboratory (based on Activity 7.1):

Dissolve about 10 g of sugar in 100 mL of water to prepare a sugar solution (this provides food for the yeast).
Take 20 mL of this sugar solution in a test tube and add a pinch of yeast granules to it.
Plug the mouth of the test tube with cotton (to allow air exchange while keeping contaminants out) and place it in a warm location.
After 1–2 hours, place a small drop of the yeast culture on a slide, cover it with a coverslip, and observe under a microscope — budding yeast cells (small outgrowths separating from the parent cell) can be seen, showing that the yeast has grown and reproduced by budding.

seed coatcotyledonradicleplumulegerminationyeastbuddingsugar solution

Marking Scheme

1(a) 1/2 mark for each correctly stated function of seed coat, cotyledon, radicle, and plumule (total 2 marks)
2OR (b) 2 marks for correctly sequenced steps: sugar solution preparation, adding yeast, incubating warmly with cotton plug, and microscopic observation of budding

Hint

For (a), think of each seed part's single defining job during germination; for (b), recall Activity 7.1's sugar-solution + yeast granules setup.

Quick Oral Answer

A seed's coat protects the embryo, the cotyledon stores its food, the radicle becomes the root, and the plumule becomes the shoot on germination; alternatively, yeast is cultured by growing it in a warm sugar solution, where it reproduces by budding, visible under a microscope.

Analysis & Explanation

This is a direct 2-mark VSA question grounded in the chapter's discussion of seed germination (Section 7.3.2, Activity 7.7, Fig. 7.9) with an internal choice testing Activity 7.1 (fission/budding in yeast, Section 7.2.1).

Part (a) draws on the chapter's statement that "the seed contains the future plant or embryo which develops into a seedling under appropriate conditions" — each seed part listed (seed coat, cotyledon, radicle, plumule) has a distinct, examinable function that must be stated precisely for full marks (1/2 mark per correct pair, or all four condensed appropriately within the 2-mark allocation).

Part (b) is drawn verbatim from Activity 7.1 in the textbook, which the chapter uses to illustrate how yeast reproduces by budding — a form of asexual reproduction distinct from binary and multiple fission described in Section 7.2.1. Students should be able to reproduce the practical steps in correct order.

Common Mistakes

1Confusing radicle (root) and plumule (shoot) directions of growth
2Saying seed coat 'stores food' (that is the cotyledon's function, not the seed coat's)
3For (b), omitting the cotton plug step or the warm-place incubation, both needed for successful yeast growth

Interesting Facts

Bengal gram (chana) seeds, as used in Activity 7.7, are commonly used in Indian classrooms to directly observe seed coat, cotyledons, radicle and plumule after soaking overnight.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2025?

This question carries 2 marks in the CBSE Class 10 Science 2025 examination.

Which chapter does this question come from in Science?

This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Sexual Reproduction in Flowering Plants / Fission — Yeast Culture (internal choice)" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2025 paper?

This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2025 paper.