DP Biology (first assessment 2025)

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Question 20N.1A.HL.TZ0.26

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.1A.HL.TZ0.26
Level HL Paper 1A Time zone TZ0
Command term Question number 26 Adapted from N/A
26.
[Maximum mark: 1]
20N.1A.HL.TZ0.26

The number of protein-coding genes in the human genome is estimated to be about 20 000, which is much less than the size of the proteome. What is one reason for this?

A. Exons are removed from RNA before translation.

B. There are more types of amino acids than nucleotides.

C. mRNA can be spliced after transcription.

D. Base substitutions occur during transcription.

[1]

Markscheme

C

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