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IB Biology SL C3.1.11 Melatonin and Sleep Questions

Explore how darkness stimulates pineal melatonin, how light suppresses secretion and how circadian rhythms regulate sleep timing in IB Biology SL C3.1.11.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Identify the pineal gland as the source of melatonin and explain that darkness or reduced light increases its secretion.
  • Explain or interpret how melatonin modulates circadian sleep timing, including jet-lag or screen-light effects.

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Study C3.1.11—Melatonin and sleep conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Biology SL C3.1.11 Melatonin and Sleep Questions question 1

[Maximum number: 2]

(a) 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.
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Question (a)

(a)

State where melatonin is produced in the body.

[ 1 ]

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 ]
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