Biology 9700 · AS & A Level · Transport mechanisms

Transport mechanisms — practice question

Many organisms use the enzyme sucrase to carry out hydrolysis of sucrose. Fig. 3.1 presents a diagram of the enzyme together with its substrate.
(a(i))[1]

State the names of the products formed when sucrose is hydrolysed.

(a(ii))[4]

With reference to Fig. 3.1, describe the mechanism by which the enzyme converts the substrate into products.

(a(iii))[1]

Copper ions ($\text{Cu}^{2+}$) inhibit the enzyme sucrase. State which type of inhibition occurs.

(b(i))[2]

Suggest the role played by sucrose in the unloading of sucrose at sinks.

(b(ii))[3]

Plant sink organs convert excess products of sucrose hydrolysis into storage molecules, such as starch. Explain why these hydrolysis products themselves cannot be stored in plant tissue.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: glucose, fructose

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