Pearson Edexcel IGCSE · Biology

Gas exchange: Practice Questions

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

9 questions28 marksFree, no account

Question 1

1 mark

Which of the following correctly describes the location and function of the bronchi in the human gas exchange system?

Question 2

1 mark

How does tar in cigarette smoke specifically affect the lungs?

Question 3

1 mark

A scientist uses hydrogen-carbonate indicator to monitor a leaf in a sealed container. During the peak of a sunny day, what color change would be observed and why?

Question 4

1 mark

Which part of the human thorax is responsible for connecting the trachea to the bronchioles?

Question 5

1 mark

During inhalation, which of the following coordinated movements occurs in the human thorax?

Question 6

4 marks

Describe two structural adaptations of the alveoli that facilitate a high rate of gas exchange, and explain how each adaptation achieves this.

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Question 7

6 marks

A leaf is kept in a sealed tube containing hydrogen-carbonate indicator. Explain why the indicator turns purple in bright sunlight but changes to yellow if the tube is placed in complete darkness, referring to the net exchange of \(CO_2\).

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Question 8

5 marks

A student investigates the net gas exchange of a leaf using hydrogen-carbonate indicator. The indicator is orange-red at atmospheric levels of carbon dioxide (\( 0.04\% \)).

(a) Explain why the indicator turns yellow when the leaf is kept in the dark for 24 hours. [2]

(b) Describe how the intensity of light affects the balance between the rate of photosynthesis and the rate of respiration, and explain the significance of the compensation point. [3]

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Question 9

8 marks

The human thorax is a specialized chamber for ventilation and the protection of the respiratory organs.
(a) Describe how the coordinated movement of the diaphragm and external intercostal muscles leads to an increase in the volume of the thorax during inhalation, and explain the effect this has on air movement into the lungs. [3]
(b) The trachea and bronchi are lined with ciliated epithelial cells and goblet cells. Describe how these cells work together to protect the lungs from dust and pathogens. [2]
(c) Smoking is a major risk factor for coronary heart disease. Explain how components in tobacco smoke, such as nicotine and carbon monoxide, contribute to the narrowing or blockage of coronary arteries. [3]

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