Exam 8: Energy, Enzymes, and Metabolism

Ascorbic acid, found in citrus fruits, acts as an inhibitor to catecholase, the enzyme responsible for the browning reaction in fruits such as apples, peaches, and pears. One explanation for the inhibiting function of ascorbic acid could be its similarity, in terms of size and shape, to catechol, the substrate of the browning reaction. If this explanation is correct, then this inhibition is most likely an example of _______ inhibition.

Which of the following effectors of enzyme activity is least likely to be of importance in cells?

The binding of a substrate to an enzyme

To be metabolized, glucose must be converted to glucose 6-phosphate. However, at equilibrium, a mixture of glucose and phosphate at concentrations that exist in cells would contain little glucose 6-phosphate. How do cells circumvent this problem?

Which of the following parameters determines how far and in what direction a reaction will proceed?

Negative feedback in a sequence of chemical reactions involves a chemical that appears _______ in the sequence and _______ reaction.

In an enzyme-catalyzed reaction,

A competitive inhibitor of the activity of an enzyme

In a chemical reaction, transition-state species have free energies that are

Use a graph to explain how temperature affects enzyme activity.

Zinc ions that bind to enzymes are called _______.

If the temperature of an enzyme-catalyzed reaction is increased from 40°C to 70°C, the rate of the reaction

A prosthetic group of an enzyme

Cells cannot create energy because _______ cannot be created or destroyed.

Chemical equilibrium

If the $\Delta$ G of a spontaneous reaction is negative, indicating that the reaction releases free energy, the reaction is _______.

Before ATP is split into ADP and P_i, it holds what type of energy?

Which statement about the feedback inhibition of enzymes is not true?

The ability of an enzyme to change shape when it binds to its substrate is called

Enzymes are sensitive to