Cambridge International A Level · Marine Science (9693)

Gas exchange: Practice Questions

5 multiple-choice questions marked as you go, and 4 written questions with worked solutions. All on Gas exchange.

9 questions21 marksFree, no account

Question 1

1 mark

A hypothetical marine organism is shaped like a cube. If the length of each side is doubled, what happens to its surface area to volume ratio (SA:V)?

Question 2

1 mark

Which statement best explains the relationship between motility and gas exchange in a tuna compared to a grouper?

Question 3

1 mark

A skipjack tuna is an obligate ram ventilator. What is the physiological consequence if this fish is prevented from swimming forward?

Question 4

1 mark

Why are coral polyps able to meet their entire oxygen requirement through simple diffusion without the need for a specialized ventilation system?

Question 5

1 mark

The diagram illustrates the process of pumped ventilation in a grouper. During the inhalation phase, what are the states of the buccal cavity volume and the opercular valve?

Question 6

2 marks

Define the term ram ventilation and name one species of marine fish that relies on this method to maintain a constant flow of water over its gills.

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Question 7

4 marks

Explain how the metabolic demand of a highly motile marine predator, such as a tuna, determines its reliance on ram ventilation to maintain gas exchange efficiency.

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Question 8

5 marks

A cube-shaped marine organism has a side length of \( 3\text{ mm} \). Calculate its surface area to volume ratio (\( SA:V \)) and explain how this ratio limits the maximum size of organisms that can rely solely on simple diffusion for gas exchange.

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Question 9

5 marks

(a) Compare the gas exchange surface of a coral polyp with that of a grouper, explaining why the grouper requires both a specialized respiratory surface and a transport system to survive. \( [3] \)
(b) Highly active marine fish, such as the skipjack tuna, utilize ram ventilation. Suggest why these organisms would face physiological stress if they were forced into a habitat with very low water flow and limited swimming space. \( [2] \)

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