Fig. 1 shows the digestive system of a runner who eats a carbohydrate-rich meal before a race. Table 1 shows information from two snacks used by the runner....
Question 1 Report
Fig. 1 shows the digestive system of a runner who eats a carbohydrate-rich meal before a race. Table 1 shows information from two snacks used by the runner. The food is digested into small soluble molecules before it can enter the blood and be used for energy by body cells.
Table 1
| snack | carbohydrate / g per 100 g | energy / kJ per 100 g |
|---|---|---|
| banana | 23 | 390 |
| oat bar | 61 | 1610 |
(a) Name the organs labelled P and Q. [2]
(b) Which snack provides more energy per 100 g? [1]
(c) Describe how the small intestine is adapted for absorbing glucose into the blood. [2]
(d) Explain why glucose is needed by muscle cells during the race. [2]
Answer Details
(a) P is the stomach and Q is the small intestine. [2]
(b) The oat bar provides more energy per 100 g, \(1610\) kJ compared with \(390\) kJ for banana. [1]
(c) The small intestine has a large surface area because of villi. Its walls are thin and it has a good blood supply, allowing glucose to be absorbed rapidly into the blood. [2]
(d) Glucose is used in respiration in muscle cells. Respiration releases energy for muscle contraction during the race. [2]
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