| Date | May 2011 | Marks available | 1 | Reference code | 11M.1.HL.TZ1.38 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 38 | Adapted from | N/A |
Question
During urine production, what happens if the water content of the blood is too low?
A. Membrane channels are produced in the cells of the collecting duct.
B. The pituitary gland stops secreting ADH.
C. The collecting duct becomes less permeable to water.
D. Large volumes of dilute urine are formed.
Markscheme
A
Examiners report
This was surprisingly the hardest question by difficulty index showing that candidates didn't know this topic. While there were concerns about the wording of answer A, the other three choices were the opposite of what happens in this situation given.
