Date | May 2022 | Marks available | 1 | Reference code | 22M.1.SL.TZ1.24 |
Level | Standard level | Paper | Paper 1 | Time zone | Time zone 1 |
Command term | Question number | 24 | Adapted from | N/A |
Question
Which process describes starch metabolism in humans?
A. Starch is digested by amylase in the mouth, stomach and small intestine.
B. Amylase digests starch into monomers of sucrose.
C. Glucose produced by the digestion of starch can be stored as glycogen.
D. Optimal activity of amylase occurs in the stomach at pH 2.
Markscheme
C
Examiners report
This question was not the hardest, but it discriminated rather poorly, implying that some of the stronger candidates answered incorrectly. The program does not specify much about starch digestion, other that it occurs in the small intestine with enzymes secreted by the pancreas, but it was still possible to identify the correct answer based on expected knowledge. The most popular answer was A, which implies incorrectly that starch is digested in the stomach. It is understandable that candidates might have thought this answer was correct, but they should have carried on to the read the other three. Answer C was undoubtedly correct — glucose from digestion of starch can be stored as glycogen. The logical conclusion is that A cannot be correct.