DP Biology (first assessment 2025)

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Question 19M.2.SL.TZ1.7a

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Date May 2019 Marks available [Maximum mark: 4] Reference code 19M.2.SL.TZ1.7a
Level SL Paper 2 Time zone TZ1
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 4]
19M.2.SL.TZ1.7a
(a)

Outline the stages in the production of mRNA by transcription.

[4]

Markscheme

a. DNA is unwound/strands are separated «by RNA polymerase» ✔

b. new nucleotides attached to template strand «by RNA polymerase» ✔

c. complementary base pairing/base pairing with an example
OR
adenine with thymine/uracil with adenine/cytosine with guanine/guanine with cytosine ✔

d. mRNA detaches from template ✔

e. DNA rewinds ✔

Examiners report

Almost all students had a clear idea of complementary base pairing and that A pairs with U in RNA. However, this question revealed weakness in the understanding of transcription and the ability to distinguish transcription from DNA replication and RNA translation. Often times candidates had hybrid answers containing information from at least two, but sometimes all three processes. Many candidates were able to gain a couple of the easier marks in 7a on transcription despite having a poor understanding of the process.

Syllabus sections