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9 Respiration occurs in cells - Edexcel - GCSE Biology - Question 9 - 2023 - Paper 2
Question 9
9 Respiration occurs in cells. (a) Why do cells respire? A to produce nitrogen B to release oxygen C to produce glucose D to release energy (b) An athlete runs ev... show full transcript
Worked Solution & Example Answer:9 Respiration occurs in cells - Edexcel - GCSE Biology - Question 9 - 2023 - Paper 2
Step 1
Step 2
(i) Explain why the breathing rate of the athlete increases when running.
Answer
The breathing rate of the athlete increases during running primarily to absorb more oxygen into the blood. This increase in oxygen allows for a higher rate of respiration, which is necessary to meet the elevated energy demands of the muscles during physical activity. Additionally, as more carbon dioxide is produced from cellular respiration, the body needs to remove this excess carbon dioxide from the blood, which also stimulates increased breathing.
Step 3
(ii) State two differences between aerobic respiration and anaerobic respiration.
Answer
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Aerobic respiration occurs in the presence of oxygen and produces a large amount of energy, along with carbon dioxide and water as byproducts. Anaerobic respiration, on the other hand, takes place in the absence of oxygen and results in a smaller amount of energy, along with lactic acid (in animals) or alcohol and carbon dioxide (in plants).
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The end products of aerobic respiration are carbon dioxide and water, while the end products of anaerobic respiration vary; they include lactic acid in animals and alcohol and carbon dioxide in yeast.