DP Biology (first assessment 2025)

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Question 21N.1A.HL.TZ1.29

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Date November 2021 Marks available [Maximum mark: 1] Reference code 21N.1A.HL.TZ1.29
Level HL Paper 1A Time zone TZ1
Command term Question number 29 Adapted from N/A
29.
[Maximum mark: 1]
21N.1A.HL.TZ1.29

Some bacteria can synthesize the amino acid isoleucine from threonine, a process involving five enzymes (E1 to E5) and four intermediary products (P, Q, R and S). The production of isoleucine is controlled by end-product inhibition.

 

 

 

 

 

 

 

 

Which statement describes this end-product inhibition?

A. If isoleucine accumulates, it inhibits the production of P.

B. End-product inhibition causes a build-up of intermediary products.

C. Isoleucine inhibits E5, so no more isoleucine is produced.

D. Isoleucine affects the structure of threonine.

[1]

Markscheme

A

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