WGU BIOCHEM Unit 3 Quiz 2022

WGU BIOCHEM Unit 3 Quiz 2022 1. Which property of enzymes is illustrated in the final step of the enzymatic cycle? a. Enzymes increase the reaction rate for a reaction. b. Enzymes lower the activation energy for a reaction. c. Enzymes are reusable. d. Enzymes are specific. Answer: C. In the final step of the enzymatic cycle, the product is released and the enzyme is able to bind to a new substrate and begin the cycle again. 2. In the enzyme cycle, which step immediately follows induced fit? a. Formation of the enzyme-substrate complex b. Release of the product and enzyme complex c. Formation of the enzyme-molecule complex d. Formation of the enzyme-product complex Answer: D. The induced fit refers to the conformational change that the enzyme undergoes when it binds to the substrate to form the enzyme-substrate complex. Therefore, the enzymatic cycle step that occurs after the induced fit is the formation of the enzyme-product complex. 3. Which type of inhibition occurs when a particular drug binds to the active site of an enzyme? a. Noncompetitive b. Irreversible c. Competitive d. Uncompetitive Answer: C. Competitive inhibitors compete with the substrate to bind to the active site of the enzyme. 4. 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? a. Significantly increase b. Slightly decrease c. Slightly increase d. Significantly decrease Answer: D. A drop in pH from 6.8 to 4.0 is a significant change in pH. Recall that the hydrogen bonds and ionic bonds that hold protein structures together can be broken by changes in pH. The disruption in protein structure due to this pH change will also significantly decrease amylase activity.