| Date | November 2021 | Marks available | 1 | Reference code | 21N.1.HL:.tz0.27 |
| Level | Higher Level | Paper | Paper 1 | Time zone | time zone 0 |
| Command term | Question number | 27 | Adapted from | N/A |
Question
Why does the brain need a continuous supply of glucose?
A. Glucose stores in the brain are located behind the blood–brain barrier and are inaccessible to the brain cells.
B. Glucose is exchanged very slowly between the blood and the brain cells, so a continuous supply is needed.
C. The quantities of glycogen stored in the brain are not sufficient for the brain’s energy requirements.
D. High glucose levels in the brain impair its function.
Markscheme
C
Examiners report
This was a hard question for candidates possibly because of the complexity of the answers for each option. If they can focus on the fact that the brain is not a good storer of glucose, it would have assisted them with their selection.
