Enzyme Activity in Cells Quiz

Which of the following factors does NOT affect enzyme activity?

• Temperature

• pH level

• Substrate concentration

• Color of the enzyme

What is meant by enzyme-substrate specificity?

• An enzyme can catalyze any reaction.

• An enzyme can only catalyze reactions with specific substrates.

• Substrates can select any enzyme for their reaction.

• Enzymes increase the activation energy of reactions.

Which of the following is an example of enzyme inhibition?

• An increase in substrate concentration speeding up the reaction.

• A decrease in temperature slowing down the reaction.

• A molecule binding to the enzyme and decreasing its activity.

• An increase in enzyme concentration speeding up the reaction.

How does temperature affect enzyme activity?

• Enzyme activity decreases with an increase in temperature.

• Enzyme activity increases with an increase in temperature, up to a point, then decreases.

• Temperature has no effect on enzyme activity.

• Enzyme activity is constant regardless of temperature changes.

What happens to enzyme activity at very high substrate concentrations?

• It stops completely.

• It decreases.

• It remains constant.

• It increases indefinitely.

What is the role of a cofactor in enzyme activity?

• It decreases the activation energy of the reaction.

• It increases the activation energy of the reaction.

• It is necessary for the enzyme's activity.

• It has no role in enzyme activity.

Which of the following best describes competitive inhibition?

• An inhibitor binds to the active site, preventing the substrate from binding.

• An inhibitor binds to a site other than the active site, changing the enzyme's shape.

• The substrate outcompetes the inhibitor for the active site.

• The enzyme changes shape to better accommodate the substrate.

How does pH affect enzyme activity?

• Enzyme activity increases with pH indefinitely.

• Enzyme activity decreases with a decrease in pH.

• Each enzyme has an optimal pH at which its activity is highest.

• pH has no effect on enzyme activity.

What effect does an increase in enzyme concentration have on the reaction rate, assuming substrate is in excess?

• The reaction rate decreases.

• The reaction rate remains constant.

• The reaction rate increases.

• The reaction rate initially increases, then decreases.