DP Chemistry (last assessment 2024)
Question 19M.3.hl.TZ2.9b
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.hl.TZ2.9b |
| Level | hl | Paper | 3 | Time zone | TZ2 |
| Command term | Explain | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
19M.3.hl.TZ2.9b
Proteins have structural or enzyme functions.
(b)
Explain why an increase in temperature reduces the rate of an enzyme-catalyzed reaction.
[2]
Markscheme
enzyme denatured/ loss of 3-D structure/conformational change
OR
«interactions responsible for» for tertiary/quaternary structures altered [✔]
shape of active site changes
OR
fewer substrate molecules fit into active sites [✔]
Examiners report
This question was well answered where most candidates received one mark for identifying that the enzyme will denature with an increase in temperature. However, many candidates did not continue with the explanation that the shape of the active site changes.
