Edexcel IGCSE Biology 2 41b Gas Exchange in Respiration and Photosynthesis Questions

Compare oxygen and carbon dioxide exchange in respiration and photosynthesis, then apply diffusion and ventilation to inhaled air, exhaled air and lung disease.

Exam points

Explain how oxygen diffuses into the blood and carbon dioxide diffuses out of the blood at the lungs.
Relate differences between inhaled and exhaled oxygen and carbon dioxide to diffusion and respiration.
Explain how reduced ventilation or blocked airways can reduce gas exchange, oxygen supply and aerobic respiration, causing breathlessness.

[Maximum number: 2]

The diagram shows parts of the human respiratory system with some structures labelled.

Figure for Question Edexcel IGCSE Biology 2 41b Gas Exchange in Respiration and Photosynthesis Questions question 1 — Edexcel IGCSE Biology

A scientist compared the rate at which oxygen is used during exercise by a person who is a non-smoker with a person who is a smoker.

The rate is measured in $\mathrm{cm}^{3}$ per minute for each kilogram of body mass.
The table shows the scientist's results.

Table for Question Edexcel IGCSE Biology 2 41b Gas Exchange in Respiration and Photosynthesis Questions question 1 — Edexcel IGCSE Biology

Calculate the volume of oxygen used in 30 minutes by a non-smoker with a mass of 70 kg .
volume =…… $\mathrm{cm}^{3}$

$35 \times 70 \times 30=73500\left(\mathrm{~cm}^{3}\right)$

One mark for $\times 35$ or $\times 70$ or $\times 30$ or 2450 or 1050 or 2100

Accept 74000 or 73000 for two marks

Correct answer gains both marks

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Edexcel IGCSE Biology 2 41b Gas Exchange in Respiration and Photosynthesis Questions question 1