Chapter 6 Post-Lec Assessment

What is activation energy (ΔG°‡)?

• The energy needed to maintain a reaction.

• The energy released during a reaction.

• The minimum energy required for a chemical reaction to occur.

• The energy required to break bonds in products.

How do catalysts affect activation energy?

• They increase activation energy.

• They have no effect on activation energy.

• They lower activation energy.

• They change the products of the reaction.

What is the Michaelis constant (Kₘ)?

• The energy required for the reaction to occur.

• The maximum reaction rate.

• The substrate concentration at which the reaction rate is half of Vmax.

• The rate constant for the formation of the enzyme-substrate complex.

What happens in zero-order kinetics?

• The reaction rate depends on substrate concentration.

• The reaction rate increases with substrate concentration.

• The reaction rate is constant and independent of substrate concentration.

• The enzyme is not saturated with substrate.

What is a competitive inhibitor?

• An inhibitor that permanently inactivates the enzyme.

• An inhibitor that binds to the allosteric site.

• An inhibitor that binds only to the enzyme-substrate complex.

• An inhibitor that binds to the active site of the enzyme.

What effect does a noncompetitive inhibitor have on Vmax?

• Vmax becomes zero.

• Vmax increases.

• Vmax decreases.

• Vmax remains the same.

What is the significance of the turnover number (kcat)?

• It indicates how quickly an enzyme can convert substrate to product.

• It measures the maximum substrate concentration.

• It determines the type of enzyme used.

• It shows the energy change in a reaction.

Which model describes the enzyme-substrate binding as a perfect fit?

• Transition state model.

• Induced fit model.

• Michaelis-Menten model.

• Lock-and-key model.

What is the effect of an uncompetitive inhibitor on Km?

• Km increases.

• Km decreases.

• Km remains the same.

• Km becomes zero.

Which enzyme name indicates that it catalyzes a reaction involving the transfer of a phosphate group?

• Kinase

• Oxidase

• Hydrolase

• Ligase