DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ1.c

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ1.c
Level hl Paper 3 Time zone TZ1
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 2]
19M.3.hl.TZ1.c

This question is about antiviral drugs.

Anti-HIV drugs, such as zidovudine, often become less effective over time.

Explain the development of resistant virus strains in the presence of antiviral drugs.

[2]

Markscheme

viruses undergo «rapid» mutation  [✔]

mutation causes a change in viral protein
OR
drug no longer binds to virus  [✔]

 

Note: Accept “rapid reproduction «allows resistant viruses to multiply»”.

Examiners report

Most candidates scored the first marking point when explaining the development of resistant virus strains but almost no-one scored the second mark. Many candidates were confused between bacteria and viruses and gave explanations about bacterial resistance and natural selection.

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