I have narrowed the following questions to 2 possible answers. I would really ap
ID: 166757 • Letter: I
Question
I have narrowed the following questions to 2 possible answers. I would really appreciate an expert’s help on which one is correct. Thank you.
1) After a 24 hour fast, which of the following is the major metabolic pathway providing oxidizable substrate for skeletal muscle?
Lipolysis
B.Gluconeogensis
C.Ketone body synthesis
Glycogenolysis
(I’m thinking B or C?)
2) Which of the following does NOT increase lipolysis?
Epinephrine
Growth Hormone
C.Insulin Like Growth Factor (IGF1)
D.Thyroid hormone
(I’m thinking C or D?)
3) Which of the following statements is consistent with protein catabolism in the fed state?
A. Glutaminase activity in the liver will be low
B. Amino acids will be used as a substrate for gluconeogenesis
C. The conversion of alpha-ketoglutarate to glutamate will be favored in the liver
D. High levels of arginine will stimulate the activity of urea synthesis
(I’m thinking A or C?)
4) A seven-year-old girl is recently diagnosed with type I diabetes. Laboratory testing shows elevated urine glucose and key tones. Blood glucose levels for 250 mg/dL (normal range 90-120 mg/dL). The increase in blood glucose in this individual is primarily due to increased activity of which of the following enzymes?
A. Glycogen synthase
B. HMG COA synthase
C. Hormone sensitive lipase
D. Fructose 1,6 bisphosphatase
(I’m thinking B or D)
Explanation / Answer
1) C. Ketone body synthesis
The inability to use glycogen or blood glucose makes phosphofructokinase-deficient muscle heavily dependent on fatty acids and ketone bodies as oxidative fuels.
2) C. Insulin Like Growth Factor (IGF1)
IGF1 lowers lipolysis
3) A. Glutaminase activity in the liver will be low
Catabolic pathways are involved in the breakdown of larger molecules, commonly involves oxidative reactions, are exothermic, produces reducing equivalents via the respiratory chain, ATP.
C. The conversion of alpha-ketoglutarate to glutamate will be favored in the liver is the metabolic process
4) B. HMG COA synthase
HMG-CoA is an intermediate in both cholesterol synthesis and ketogenesis. This reaction is over-activated in patients with diabetes mellitus type 1 if left untreated, due to prolonged insulin deficiency and the exhaustion of substrates for gluconeogenesis and the TCA cycle. This results in shunting of excess acetyl-CoA into the ketone synthesis pathway through HMG-CoA synthase, leading to the development of diabetic ketoacidosis.
Fructose 1,6-bisphosphatase plays a major role treating type 2 diabetes.