DP Chemistry (last assessment 2024)

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Question 18M.3.sl.TZ1.13c.ii

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Date May 2018 Marks available [Maximum mark: 2] Reference code 18M.3.sl.TZ1.13c.ii
Level sl Paper 3 Time zone TZ1
Command term Describe Question number c.ii Adapted from N/A
c.ii.
[Maximum mark: 2]
18M.3.sl.TZ1.13c.ii

Many drugs, including aspirin, penicillin, codeine and taxol, have been modified from compounds that occur naturally.

(c.ii)

Describe how penicillin combats bacterial infections.

[2]

Markscheme

Any two of:

ring is «sterically» strained

OR

ring breaks up/opens/reacts «easily»

OR

amide/amido group «in ring» is «highly» reactive

 

«irreversibly» binds/bonds to enzyme/transpeptidase

OR

inhibits enzyme/transpeptidase «in bacteria» that produces cell walls

OR

prevents cross-linking of bacterial cell walls

 

cells absorb water AND burst

OR

cells cannot reproduce

 

Award [1 max] for “interferes with cell wall production”.

Do not accept “cell membrane” instead of “cell wall”.

[2 marks]

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