DP Biology (last assessment 2024)

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Question 22N.2.SL.TZ0.3a

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Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.2.SL.TZ0.3a
Level SL Paper 2 Time zone TZ0
Command term Draw Question number a Adapted from N/A
a.
[Maximum mark: 1]
22N.2.SL.TZ0.3a

The diagram shows the molecular structure of the amino acid leucine.

(a)

Draw a circle on the diagram to enclose the carboxyl group.

[1]

Markscheme

No mark if C1 in chain is included.

Examiners report

The carboxyl group was not well known in (a). In b, the classic answers of insulin or glucagon were expected, but a disturbing number gave answers that were neither proteins nor hormones. In (c) most were able to gain a mark for the enzyme lactase, and either the products of digestion or the fact that the enzyme is immobilised. Weaker candidates tried to explain lactose intolerance instead of answering the question.

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