| Date | May 2009 | Marks available | 1 | Reference code | 09M.1.HL.TZ1.26 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 26 | Adapted from | N/A |
Question
Which best describes the tertiary structure of a protein?
A. The interaction of polypeptide subunits and prosthetic groups
B. Interactions forming hydrogen bonds between the amino acids
C. The sequence of amino acids in the polypeptide chain
D. The structure formed from interactions between the amino acid side groups
Markscheme
D
Examiners report
This question had a high discrimination index, showing that it did not show difficulty for good candidates. Even if hydrogen bonds are very important in the tertiary structure of proteins, it is the interactions between the side groups of amino acids that determines the tertiary structure.
