DP Biology (first assessment 2025)
Question 21N.2.SL.TZ0.2a
Date | November 2021 | Marks available | [Maximum mark: 1] | Reference code | 21N.2.SL.TZ0.2a |
Level | SL | Paper | 2 | Time zone | TZ0 |
Command term | Label | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 1]
21N.2.SL.TZ0.2a
(a)
The figure shows a tripeptide.
Label one peptide bond in this molecule.
[1]
Markscheme
circle/bracket around peptide bond / arrow pointing to peptide bond / peptide bond labelled;
Allow either peptide bond
Allow if adjacent C=O and NH groups are included in the circle/bracket, but do not allow if other parts of the molecule are included
Examiners report
However, in part 2b, many did not describe the functions of the named proteins correctly. Common mistakes were assuming that all hormones are proteins, with many incorrectly giving oestrogen, testosterone and thyroxin for example. Examples were anticipated from the list of proteins found in section 2.4 of the guide.
