Biology 9700 · AS & A Level · Transport mechanisms

Transport mechanisms — practice question

(a)[3]

Explain what the description ‘an inevitable consequence of gas exchange in leaves’ means.

(b)[3]

Explain the role of hydrogen bonding in the transport of water in the xylem.

(c)[4]

Use Fig. 4.2A to compare the transpiration rates of emergent, canopy and suppressed trees over $14$ hours in the forest.

(d)[4]

Transpiration rate is affected by conditions that differ a lot from place to place inside forests. Use the information in Fig. 4.1 and Fig. 4.2 to suggest why emergent and suppressed trees have different transpiration rates.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: Stomata need to open for carbon dioxide uptake

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