Question 1

Paper 2Easy6 marks

A student exposes equal samples of the same enzyme to different conditions for 10 minutes. The student then measures the activity of each sample at pH 7 and 25 °C.

Conditions during exposureRelative enzyme activity afterwards (% of untreated control)
pH 7, 25 °C (untreated control)100
pH 7, 80 °C8
pH 2, 25 °C12
(a)

State three features of polypeptide chains that allow a wide variety of polypeptides to exist.

[3]
(b)

Use the results in the table.

(i)

Identify the exposure condition that resulted in the lowest enzyme activity.

[1]
(ii)

State the term for the change in protein structure that can be caused by high temperature or extreme pH, and state one effect of this change on enzyme function.

[2]

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