Bioc 212 Tutorial 4

The multistep pathways of metabolism are efficient because they

• Locate all of the enzymes for a pathway in the same place within the cell

• Use the same substrate for all of the enzymes in the pathway

• Use the same enzyme for all of the substrates in the pathway

• Spread the enzymes for a pathway into several different organelles

The active site of an enzyme is the region that

• binds allosteric regulators of the enzyme.

• is involved in the catalytic reaction of the enzyme.

• binds noncompetitive inhibitors of the enzyme.

• is inhibited by the presence of a coenzyme or a cofactor

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

• by binding at the active site of the enzyme

• by changing the shape of the enzyme's active site

• by changing the free energy change of the reaction

• by acting as a coenzyme for the reaction

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

• denaturization of the enzyme

• allosteric inhibition

• competitive inhibition

• saturation of the enzyme activity

According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?

• The binding of the substrate depends on the shape of the active site.

• Some enzymes change their structure when activators bind to the enzyme.

• A competitive inhibitor can outcompete the substrate for the active site.

• The binding of the substrate changes the shape of the enzyme's active site.

What role do cofactors play in enzyme activity?

• They are products of the enzymatic reaction.

• They inhibit the enzyme's function.

• They enhance the enzyme's activity.

• They are substrates for the enzyme.

What effect does a competitive inhibitor have on the rate of an enzyme-catalyzed reaction?

• It increases the reaction rate by providing additional substrate.

• It decreases the reaction rate by binding to the active site.

• It changes the enzyme's structure permanently.

• It has no effect on the reaction rate.

Which of the following statements best describes the role of an enzyme's active site?

• It is the region that determines the enzyme's overall shape.

• It is the location where substrates are converted into products.

• It is where allosteric inhibitors bind to regulate enzyme activity.

• It is the site where cofactors are permanently attached.

How do temperature changes typically affect enzyme activity?

• Lower temperatures increase the reaction rate significantly.

• Temperature has no effect on enzyme activity.

• Enzymes become denatured at extreme temperatures, reducing activity.

• Higher temperatures always increase enzyme activity.

Every reaction in a metabolic pathway is

• reversible

• Catalyzed by a specific enzyme

• Controlled by the end product

• Either reversible or irreversible