DP Chemistry (last assessment 2024)
Question 17N.3.hl.TZ0.11a
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.3.hl.TZ0.11a |
| Level | hl | Paper | 3 | Time zone | TZ0 |
| Command term | Determine | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
17N.3.hl.TZ0.11a
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.
(a)
Determine the value of the Michaelis constant, Km, by annotating the graph.
[2]
Markscheme
Km labelled on x-axis as the [succinate ion] at ½Vmax
OR
horizontal line at ½Vmax AND vertical line down to x-axis
«Km ＝» 6.5 x 10–3 «mol dm–3»
Annotation of graph required for M1.
Accept any specific value in the range 6.0 x 10–3 to 7.5 x 10–3 «mol dm–3».
