DP Biology (first assessment 2025)

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Question 20N.1A.SL.TZ0.27

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.1A.SL.TZ0.27
Level SL Paper 1A Time zone TZ0
Command term Question number 27 Adapted from N/A
27.
[Maximum mark: 1]
20N.1A.SL.TZ0.27

Which are two proteins that assist in the unwinding and separation of DNA strands during replication?

A. Helicase and DNA polymerase III

B. DNA gyrase and DNA polymerase I

C. Helicase and DNA primase

D. Single-strand binding protein and DNA gyrase

[1]

Markscheme

D

Examiners report

For reasons that are hard to explain, this question had one of the highest ever discrimination indices at 0.72, with about half of candidates answering correctly.

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