Gas exchange happens in the alveoli in the lungs. Figure 7 shows an alveolus and a capillary. (a) (i) Name the gas used in respiration that moves from the alveolus into the capillary. (ii) Name the gas produced by respiration that moves from the capillary into the alveolus. (iii) The capillary wall is only one cell thick. Explain how gases move from the alveolus to the capillary.

GCSE Edexcel Biology Combined Science Diffusion, Osmosis, and Active Transport: Gas exchange happens in the alve

Gas exchange happens in the alveoli in the lungs - Edexcel - GCSE Biology Combined Science - Question 4 - 2023 - Paper 2

Question 4

Gas exchange happens in the alveoli in the lungs. Figure 7 shows an alveolus and a capillary. (a) (i) Name the gas used in respiration that moves from the alveolus... show full transcript

Worked Solution & Example Answer:Gas exchange happens in the alveoli in the lungs - Edexcel - GCSE Biology Combined Science - Question 4 - 2023 - Paper 2

Step 1

Name the gas used in respiration that moves from the alveolus into the capillary.

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Answer

The gas used in respiration that moves from the alveolus into the capillary is oxygen (O₂).

Step 2

Name the gas produced by respiration that moves from the capillary into the alveolus.

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Answer

The gas produced by respiration that moves from the capillary into the alveolus is carbon dioxide (CO₂).

Step 3

Explain how gases move from the alveolus to the capillary.

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Answer

Gases move from the alveolus to the capillary primarily by diffusion.

By diffusion: This process occurs as gases naturally spread from areas of higher concentration to areas of lower concentration.
Down a concentration gradient: The oxygen concentration is typically higher in the alveolus than in the blood within the capillary; thus, oxygen diffuses into the blood. Conversely, carbon dioxide concentration is higher in the blood, promoting its diffusion into the alveolus.
Through a membrane: This movement occurs across the thin alveolar wall, which serves as a semipermeable membrane, allowing easy passage for these gases.

Gas exchange happens in the alveoli in the lungs - Edexcel - GCSE Biology Combined Science - Question 4 - 2023 - Paper 2

Worked Solution & Example Answer:Gas exchange happens in the alveoli in the lungs - Edexcel - GCSE Biology Combined Science - Question 4 - 2023 - Paper 2

Name the gas used in respiration that moves from the alveolus into the capillary.

Name the gas produced by respiration that moves from the capillary into the alveolus.

Explain how gases move from the alveolus to the capillary.

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