IB Biology HL 3.1.11 Melatonin and circadian rhythms Question Bank
Practise IB Biology HL 3.1.11 by analysing hormonal control of circadian rhythms and jet-lag evidence.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Analyse how melatonin secretion controls circadian timing and sleep-wake cycles.
- Evaluate hormonal and environmental causes of disrupted circadian rhythms.
C3.1.11—Melatonin and sleep question 1
[Maximum number: 2]
Melatonin helps to control circadian rhythms in the body. The graph shows the mean levels of melatonin in the body in day and night workers over 24 hours.
Question (a)
(a)
State where melatonin is produced in the body.
[ 1 ]
pineal gland;
"Brain" not sufficient
Question (b)
(b)
Deduce, with a reason, what time of day would be a good time to take melatonin if you have travelled over several different time zones and are jet-lagged on your arrival.
[ 1 ]
Time of day: around 18:00 (locally); OR time that is in the range of local standard bed time;
Reason: need to re-establish the increase that occurs after 18:00 hours / reestablish circadian rhythm / OWTTE;
OWTTE
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