Sahitha International Science Academy
Edexcel General Science Biology
LET’S REVISE 07
GAS EXCHANGE
1. The structures below are found in the human bronchial tree.
1. Alveoli
2. Trachea
3. Bronchioles
4. Bronchi
Which of the following shows the route taken by air after it is breathed in through the
mouth?
a. 2
3
4
1
b. 1
4
3
2
c. 2
4
3
1
d. 4
1
2
3
2. Which of the following is not a feature of an efficient gas exchange surface?
A. thick walls
B. moist lining
C. close proximity to blood capillaries
D. Large surface area
3. Which row in the table shows the correct percentage of oxygen in atmospheric air and
exhaled air?
Atmospheric air / %
Exhaled air / %
A
78
21
B
21
16
C
16
4
D
4
0.04
1|Page
Sahitha Karapitiya (BSc UG)
SCIENCE From Quantum To Cosmos
Sahitha International Science Academy
Edexcel General Science Biology
4. Copy and complete the table, which shows what happens in the thorax during ventilation
of the lungs. Two boxes have been completed for you.
Action during inhalation
external intercostal muscles
internal
intercostal muscles
Action during exhalation
contract
ribs
move down and in
diaphragm
volume of thorax
pressure in thorax
volume of air in lungs
5. A student wrote the following about the lungs.
The student does not have a good understanding of the workings of the lungs. Re-write their
description, using correct biological words and ideas.
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Sahitha Karapitiya (BSc UG)
SCIENCE From Quantum To Cosmos
Sahitha International Science Academy
Edexcel General Science Biology
6. Sometimes, people injured in an accident such as a car crash suffer from a pneumothorax.
This is an injury where the chest wall is punctured, allowing air to enter the pleural cavity
(see Figure a). A patient was brought to the emergency department of a hospital, suffering
from a pneumothorax on the left side of his chest. His left lung had collapsed, but he was
able to breathe normally with his right lung.
(Figure a)
a. Explain why a pneumothorax caused the left lung to collapse.
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Sahitha Karapitiya (BSc UG)
SCIENCE From Quantum To Cosmos
Sahitha International Science Academy
Edexcel General Science Biology
b. Explain why the right lung was not affected.
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c. If a patient's lung is injured or infected, a surgeon can sometimes 'reset' it by
performing an operation called an artificial pneumothorax. What do you think might
be involved in this operation?
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4|Page
Sahitha Karapitiya (BSc UG)
SCIENCE From Quantum To Cosmos