Biology 5090 · O Level · Diffusion and osmosis

Diffusion and osmosis — practice question

Fig. 1 illustrates cells from a plant tissue that were placed on a slide in distilled water and examined with a microscope. Fig. 2 illustrates cells from the same plant tissue after they had been placed on a slide in concentrated salt solution.
(a)[4]

Explain why the cells in Fig. 2 appear this way.

(b(i))[2]

Identify the structures labelled P and Q in Fig. 2.

(b(ii))[1]

State what is present in location R in Fig. 2.

(b(iii))[3]

The concentrations of substances in structure Q are not the same as those in location R. Explain how the features of structure P lead to differences in the concentrations of substances in Q and R.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: membrane or P / cytoplasm or Q moving away from wall

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