EXAM I ANSWER KEY BIOCHEMISTRY 462B - SPRING 2007 Question 1.(8 points) Describe the difference between mass action ratio Qand equilibrium constant Keq. How are they related to each other mathematically through free energy change? Qrefers to the actual ratio of product and substrate concentrations in a cell while Keqrefers to the ratio of product and substrate concentrations at equilibrium. ±G=²RTlnKeq+RTlnQQuestion 2.(12 points) What are the effects of the following events on the rates of glycogen synthesis and glycogen degradation? Describe the effects as increase, decrease, or no effect. Glycogen Glycogen Synthesis Degradation (A) Increase in intracellular Ca2+levels (B) Increase in circulating insulin (C) Decrease in blood glucose levels (D) Increase in circulating epinephrine (E) Increase in cAMP levels (F) Increase in AMP levels Synthesis Degradation (A) Increase in intracellular Ca2+levels No effect Increase (B) Increase in circulating insulin Increase Decrease (C) Decrease in blood glucose levels Decrease Increase (D) Increase in circulating epinephrine Decrease Increase (E) Increase in cAMP levels Decrease Increase (F) Increase in AMP levels Decrease or no effect* Increase * AMP-activated protein kinase will decrease glycogen synthesis Question 3.(8 points) What are the regulatory enzymes (or steps) in glycolysis? What is the common trait that sets apart the reactions they catalyze from the other reactions in glycolysis?
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