Cambridge IGCSE · Sciences - Co-ordinated (Double) (0654)

Gas exchange in humans: Practice Questions

5 multiple-choice questions marked as you go, and 2 written questions with worked solutions. All on Gas exchange in humans.

7 questions16 marksFree, no account

Question 1

1 mark

When carbon dioxide is bubbled through a test tube containing limewater, what observation is expected if the gas is present?

Question 2

1 mark

Which feature of the alveoli helps to maintain a steep concentration gradient for the diffusion of oxygen into the blood?

Question 3

1 mark

During expiration (breathing out) in a human, what is the state of the external intercostal muscles and the diaphragm?

Question 4

1 mark

A student investigates the composition of air by exhaling into a test-tube containing a specific indicator. Which observation and conclusion regarding expired air would be correct?

Question 5

1 mark

Which statement best explains the link between physical activity and the depth of breathing in humans?

Question 6

5 marks

Explain the physiological mechanism that links vigorous physical activity to an increase in both the rate and depth of breathing in humans, starting from the accumulation of a specific waste gas in the blood.

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

Question 7

6 marks

Explain how the brain responds to an increased concentration of carbon dioxide (\(CO_2\)) in the blood during vigorous exercise to modify the depth and rate of breathing.

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

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