Biology 9700 · AS & A Level · Testing for biological molecules

Testing for biological molecules — practice question

Glycogen and cellulose are polymers. Fig. 2.1 illustrates small, representative sections of a glycogen molecule and a cellulose molecule.
(a)[3]

Describe three visible ways, shown in Fig. 2.1, in which the glycogen molecule is different from the cellulose molecule.

(b)[3]

Glycogen occurs as granules in mammalian liver and muscle cells. Fig. 2.2 shows a diagram of part of a glycogen molecule taken from a glycogen granule. Explain how the structure of glycogen is linked to its function in cells.

(c)[3]

Explain how the arrangement of cellulose molecules in plant cell walls is linked to their function.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Glycogen is branched whereas cellulose is unbranched

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