DP Chemistry (last assessment 2024)
Question 17N.3.hl.TZ0.11b.i
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.3.hl.TZ0.11b.i |
| Level | hl | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | b.i | Adapted from | N/A |
b.i.
[Maximum mark: 2]
17N.3.hl.TZ0.11b.i
An enzyme catalyses the conversion of succinate to fumarate ions in a cell, as part of the process of respiration.
The rate of the reaction was monitored and the following graph was plotted.
(b.i)
The malonate ion acts as an inhibitor for the enzyme.
Suggest, on the molecular level, how the malonate ion is able to inhibit the enzyme.
[2]
Markscheme
similar shape/size/structure «as succinate ion/substrate»
competes for the active site «with the succinate ion/substrate»
Accept “competitive inhibitor” for M2.
Award [1 max] if non-competitive inhibition is correctly described.
