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A person is undergoing prolonged fasting. His urine will be found to contain abnormal quantities of -
A
Fats
B
Amino acids
C
Ketones
D
Glucose
Detailed Solution
During prolonged fasting the carbohydrate stores (glycogen) of the body are soon used up.
The body then breaks down large amounts of stored fat for energy.
The oxidation of fatty acids produces a large amount of acetyl CoA, which cannot all be oxidised in the Krebs cycle because oxaloacetate is in short supply.
The excess acetyl CoA is converted in the liver into ketone bodies (acetoacetic acid, $\beta$-hydroxybutyric acid and acetone).
Their level in the blood rises (ketosis), and they are excreted in the urine (ketonuria).
Glucose does not appear in the urine, because the blood glucose is low.
So the urine will contain abnormal quantities of ketones.
The body then breaks down large amounts of stored fat for energy.
The oxidation of fatty acids produces a large amount of acetyl CoA, which cannot all be oxidised in the Krebs cycle because oxaloacetate is in short supply.
The excess acetyl CoA is converted in the liver into ketone bodies (acetoacetic acid, $\beta$-hydroxybutyric acid and acetone).
Their level in the blood rises (ketosis), and they are excreted in the urine (ketonuria).
Glucose does not appear in the urine, because the blood glucose is low.
So the urine will contain abnormal quantities of ketones.