IB Biology HL 3.3.10 Osmoregulation by collecting ducts Question Bank
Practise IB Biology HL 3.3.10 by applying osmoregulation by collecting ducts concepts to exam-style questions.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- identify the relevant biological structure, process or evidence
- apply the correct biological mechanism to the question
- evaluate the result using data, adaptation or ecological reasoning
D3.3.10 (HL)—Osmoregulation by collecting ducts question 1
[Maximum number: 4]
Feedback mechanisms are used in living organisms both to promote and respond to change.
Outline the role of ADH in osmoregulation.
a. ADH (secreted by pituitary) if body/blood is dehydrated/hypertonic/has high solute concentration;
b. more aquaporins / aquaporins open (in collecting duct);
c. collecting duct more permeable to water/reabsorbs more water (from filtrate/urine);
d. water reabsorbed by osmosis/water reabsorbed because medulla is hypertonic;
e. (reabsorbed) water passes (from filtrate) to blood / blood solute concentration reduced;
f. less water lost in urine / smaller volume of (more concentrated) urine;
g. negative feedback / less/no ADH secreted when blood solute concentration returns to normal;
Marking guidance:
Do not accept answers suggesting that ADH has a different effect when body fluids are hypotonic.
[4 max]
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