The diagram shows capillaries carrying blood through muscle - Edexcel - GCSE Biology - Question 2 - 2017 - Paper 1
Question 2
The diagram shows capillaries carrying blood through muscle.
(a) Complete the sentence by putting a cross (X) in the box next to your answer.
The blood vessel that... show full transcript
Worked Solution & Example Answer:The diagram shows capillaries carrying blood through muscle - Edexcel - GCSE Biology - Question 2 - 2017 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The blood vessel that transports oxygenated blood from the heart is the
☐ C pulmonary vein.
Step 2
Explain how the concentration gradient is maintained between the blood and muscles.
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Answer
The concentration gradient is maintained as oxygen is used in the muscles for cellular respiration, lowering its concentration in the muscle tissues. This creates a higher concentration of oxygen in the blood flowing through the capillaries, thus allowing oxygen to diffuse from the blood into the muscles. Additionally, carbon dioxide produced during respiration increases in the muscle cells, maintaining the gradient as it diffuses back into the bloodstream where its concentration is lower.
Step 3
Complete the word equation for aerobic respiration.
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Answer
GLUCOSE + oxygen → carbon dioxide + WATER
Step 4
Describe the relationship between cardiac output and running speed.
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Answer
As running speed increases, cardiac output increases. This is typically linear up to speeds of 12 to 16 km per hour, after which the increase in cardiac output becomes slower.
Step 5
Explain why this runner gets muscle cramp when he runs at speeds over 24 km per hour.
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Answer
The runner likely experiences muscle cramps at high speeds due to anaerobic respiration, which leads to the build-up of lactic acid in the muscles when the oxygen supply is insufficient. This can cause discomfort and cramping as a result of muscle fatigue.
