2.4.1 Cell Structure and Function (Structured Question 1 & 2)


Question 1:
Diagram below shows a plant cell as seen under an electron microscope.

(a)(i)
On the diagram, label the structures A, B, C and D. (2 marks)
(a)(ii) State the function of structure A and structure D. (2 marks)
(b) Explain the role of C to maintain cell turgidity. (2 marks)
(c) Every somatic cell which contains structure B has a potential to form a complete new organism.
(i) Name the technique used to produce new plants in large quantities. (1 mark)
(ii) By using one suitable part of the plant, explain the technique in (c)(i). (4 marks)



Answer:
(a)(i)
A: Chloroplast
B: Nucleus
C: Vacuole
D: Golgi apparatus

(a)(ii)
A: Absorbs light energy for photosynthesis.
D: Collects chemical produced and pack them in a membrane to form secretory granules.

(b)
– Maintain the osmotic concentration of the cell sap.
– If the cell is flaccid, more water will enter the cell by osmosis.

(c)(i)
Culture tissue / Cloning

(c)(ii)
– Use shoot / root / meristem issue
– Wash and treat with the sterilizing agent hydrogen peroxide.
– The tissue or explant is cultured in a nutrient medium, at a suitable temperature and pH value.
– Cells divide by mitosis to form a callus.
– The callus differentiates to form a clone.


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