Biology 9700 · AS & A Level · Transport mechanisms

Transport mechanisms — practice question

Transport proteins move sugar molecules into cells.
(a)[2]

Explain why transport proteins are needed to move sugar molecules, such as glucose and fructose, into cells.

(b)[5]

Using the information in Fig. 5.1, explain how sucrose: • enters the companion cell • passes from the companion cell into the sieve tube element.

(c)[1]

Sucrose is transported through phloem sieve tubes to sinks. State two examples of sinks.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: sugars are hydrophilic, polar and water-soluble

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