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bioch. q - raheem
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03-08-2011, 07:17 PM
Which of the following statements about the enzymes, glucokinase and/or hexokinase is correct? a) Glucokinase has a high affinity for glucose. b) Hexokinase has a high affinity for glucose. c) Hexokinase has a higher Km for glucose than has glucokinase. d) Glucokinase has a lower Km for glucose than has hexokinase
03-08-2011, 07:20 PM
GOOD
Which of the following statements about the enzymes, glucokinase and/or hexokinase is correct? Your Answer: b) Hexokinase has a high affinity for glucose. Feedback: Glucokinase is found in the liver (and pancreas), and hexokinase is found in most other tissues. They are isoenzymes. Both enzymes form glucose-6-phosphate from glucose; glucokinase has a low affinity for glucose and functions when the intracellular concentration of glucose in the liver is high (such as after a meal). The liver is not dependent on glucose for energy as it can use fatty acids. It stores glucose as glycogen, and when these stores are filled, converts it to fat. Hexokinase has a high affinity for glucose so can function even when glucose levels are low. It is present in brain and other tissues. Depending on the tissue, glucose-6-phosphate can either provide energy via glycolysis or it can be converted to glucose-1-phosphate for the synthesis of glycogen. Page reference: Page 167 |
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