The Rate of an Enzyme-Catalyzed Reaction Initially Increases with an Increase

question 11

Multiple Choice

The rate of an enzyme-catalyzed reaction initially increases with an increase in the substrate concentration,but eventually reaches a maximum value,even though the concentration of substrate continues to increase.Which of the following best explains why?

• A)As substrate concentration increases,the substrates preferentially bind with each other instead of the active site of the enzyme,and no additional catalysis occurs.
• B)As substrate concentration increases,the active sites of all the enzyme molecules become occupied with substrate molecules,and no additional binding can occur.
• C)An increase in substrate concentration eventually increases the temperature of the reaction mixture,and the enzyme becomes denatured.
• D)An increase in substrate concentration allows for greater competition between substrate and inhibitor binding,and enzyme activity ceases.
• E)When substrate concentrations become too high,local variations of pH occur that cause the enzyme to become denatured.

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Definitions:

Profitability Index

A financial metric that measures the profitability of an investment, calculated as the present value of future cash flows divided by the initial investment cost.

Net Present Value

Net Present Value (NPV) is the difference between the present value of cash inflows and the present value of cash outflows over a period of time, used to evaluate the profitability of an investment.

Payback

The period of time required for the return on an investment to "repay" the original investment cost.

Discounted Payback

A capital budgeting method that calculates the time required to recoup an investment based on discounted cash flows.