Biology 9700 · AS & A Level · Transport mechanisms

Transport mechanisms — practice question

Fig. 5.1 shows an electron micrograph of a transverse section of part of a plant stem.
(a)[1]

Name structure A shown in the micrograph.

(b(i))[1]

Name one assimilate carried by these cells.

(b(ii))[2]

Give one example of a source and one example of a sink.

(c)[5]

Describe how the assimilate you named in (b)(i) is moved from the source to the sink.

(d)[1]

Aphids have mouthparts adapted for piercing the plant cells that carry assimilates. Suggest why aphids feed specifically from these cells.

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