DP Biology (first assessment 2025)

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Question 22N.2.HL.TZ0.4b

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Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.2.HL.TZ0.4b
Level HL Paper 2 Time zone TZ0
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 1]
22N.2.HL.TZ0.4b
(b)

Outline how nucleosomes affect the transcription of DNA.

[1]

Markscheme
  1. (nucleosomes can) promote AND inhibit transcription of genes/expression of genes;
  2. (nucleosomes can) prevent transcription by (tight) condensation/supercoiling/packing of DNA;
  3. (nucleosomes can) allow/prevent binding of RNA polymerase/transcription factors;
  4. tagging/acetylation/methylation of nucleosomes/histones can promote/inhibit transcription;
  5. movement of histones/nucleosomes (along DNA) can affect which genes are transcribed;

‘Affects transcription’ is in the question — no mark.

Examiners report

Many candidates knew something of the role of nucleosomes in regulating DNA transcription. A wide range of answers was accepted for the single mark.

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