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

Testing for biological molecules — practice question

Fig. 1.1 shows a transmission electron micrograph of cells taken from a plant leaf.
(a(i))[3]

Name the structures X, Y and Z in the cell.

(a(ii))[2]

State two ways in which an animal cell's structure differs from that of plant cells such as those in Fig. 1.1.

(b(i))[2]

Cell structure Y in Fig. 1.1 contains a large starch granule (grain). Name the chemical reagent used to test for starch and state the colour change seen if starch is present.

(b(ii))[4]

Starch granules contain amylose and amylopectin. Describe the similarities and differences between the structure of amylose and the structure of amylopectin.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: X is the nucleus.

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