BMAT Q5: Enzymes and pH

The browning of fruit involves enzymes.
The time taken for slices of

apple kept in different solutions to turn brown is shown in the table. The effect of pH and sodium chloride concentration was investigated. All other variables were kept constant.
apple slice
sodium chloride concentration / mol dm–3
time taken for the apple to brown
/ minutes
1 3.0 2 5.0 3 7.0 4 9.0 5 7.0
0.0 22 0.0 10 0.0 6 0.0 6 0.5 15
A student used the data to make the following statements about these enzyme-catalysed reactions.
Which of these statements is/are correct?
1 The enzymes involved in browning are denatured in weakly alkaline conditions.
2 The optimum pH for the enzymes is pH 7.0.
3 The enzymes are activated by sodium chloride.
A none of them
B 1only
C 2only
D 3only
E 1and2only
F 1and3only
G 2and3only
H 1,2and3


i think you have access to the summer course, ari made an explanation video, also you can see the answer to this question in ari’s students if you scroll down a bit