BIOCHEM QUIZ AND EXTRA QUESTIONS, UNIT 3

BIOCHEM QUIZ AND EXTRA QUESTIONS, UNIT 3Which property of enzymes is illustrated in the final step of the enzymatic cycle? ANSWERS: Enzymes are reusable. In the enzyme cycle, which step immediately follows induced fit? ANSWERS: Formation of the enzyme-product complex Which type of inhibition occurs when a particular drug binds to the active site of an enzyme? ANSWERS: Competitive Salivary amylase, an enzyme responsible for partial digestion of carbohydrates, has optimum activity at a pH value of 6.8. What is the impact on the activity if the pH is decreased to 4.0? ANSWERS: Significantly decrease Low levels of glutathione are associated with certain types of ovarian and breast cancers. In the synthesis of glutathione, glutathione accumulates in the cell, binding to an enzyme in the pathway and temporarily preventing the synthesis of glutathione. Which type of inhibition is described by this scenario? ANSWERS: Feedback Lipase is an enzyme with an optimum temperature of 98.6°F and an optimum pH of 7.0 in the duodenum in the human body. If a person is experiencing a fever of 99.8°F, what will increase the activity of the lipase enzyme? ANSWERS: Decrease in temperature The enzyme glucokinase only binds its substrate glucose and converts glucose into the product glucose-6-phosphate. Which property of enzymes is described by this scenario? ANSWERS: Specificity Low levels of glutathione are associated with neurological, immunological, and cardiovascular impairments. Two enzymatic reactions are involved in the synthesis of glutathione. In the second enzymatic reaction, glutathione synthetase converts glycine to glutathione. What would potentially decrease risks associated with low levels of glutathione? ANSWERS: Increasing the amount of glycine in the diet Which class of enzymes impacts protein function by temporarily removing a phosphate? ANSWERS: Phosphatase How does the activation energy of enzyme-catalyzed reactions compare to those of corresponding uncatalyzed reactions? ANSWERS: The activation energy of enzyme-catalyzed reactions are lower than the uncatalyzed reactionA final product of a four-step metabolic pathway serves as a noncompetitive inhibitor, binding to an enzyme in this pathway and temporarily turning off the pathway. Which enzyme is most likely to be targeted by the inhibitor? ANSWERS: The first enzyme in the pathway