Cambridge International A Level · Marine Science (9693)

Osmoregulation: Practice Questions

5 multiple-choice questions marked as you go, and 3 written questions with worked solutions. All on Osmoregulation.

8 questions16 marksFree, no account

Question 1

1 mark

Which of the following statements about euryhaline organisms is correct?

Question 2

1 mark

Identify the physiological adaptation that allows salmon to function as euryhaline osmoregulators during their migration from the ocean to fresh water.

Question 3

1 mark

If a stenohaline marine invertebrate is placed in a solution with a water potential of \(\Psi = -100\) kPa, while its internal fluids are \(\Psi = -2500\) kPa, what is the most likely immediate outcome?

Question 4

1 mark

In the context of osmoregulation, what is the primary function of specialized chloride cells in the gills of a tuna?

Question 5

1 mark

In the context of osmoregulation, why is it necessary for a marine bony fish (an osmoregulator) to actively pump ions out of its body?

Question 6

2 marks

State the main difference between the internal osmotic concentration of a marine mussel and the concentration of the surrounding sea water.

Write your answer out first, then check it against the worked solution.

Question 7

4 marks

Compare the strategies used by osmoconformers and osmoregulators to manage internal salinity, and provide a named example for each group.

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Question 8

5 marks

A salmon moves from an area of high salinity to a river. Explain how the direction of ion movement across its gill filaments must change to prevent a loss of internal homeostasis.

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