In starvation, brain utilizes glucose preferentially but not in liver becausea) Low km value of hexokinaseb) Low km glucokinasec) High km glucokinased) High blood flow
Correct Answer: ac
Description: Glucokinase has high Km value, i.e. low affinity for glucose. That means glucokinase acts only when glucose concentration is high (as in absorptive/fed state). It is dormant when glucose concentration is low (as in postabsorptive -fasting state). Liver contains glucokinase, therefore it cannot utilize glucose in starvation as glucose concentration is low and glucokinase is dormant. In fact, this is a welcome response as it spares glucose for the organs which are exclusively dependent on glucose for energy requirement, e.g. brain.
Hexokinase, on the other hand, has low Km value, i.e. high affinity for glucose. It can utilize glucose even in lower concentrations. The brain contains hexokinase, therefore it can utilize glucose in starvation.
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now