Factors Affecting Enzyme Activity

Which of the following does not affect enzyme activity?

• temperature

• pH

• substrate concentration

• sugar

Which refers to a molecule upon which an enzyme acts?

• cofactor

• coenzyme

• substrate

• substance

What will happen when enzyme is denatured?

• A proton is added or removed from the enzyme.

• It reaches its temperature at which it exhibits maximum activity.

• A substance binds to it which slows or stops its normal catalytic function.

• It changes shape and the active site no longer matches the shape of the substrate molecule.

The graph shows the effect of altering a factor on the rate of an enzyme controlled reaction. What should be on the x-axis?

• pH

• enzyme concentration

• substrate concentration

• temperature

TRUE OR FALSE. The enzyme activity gradually lowers as the temperature rises more than the optimal temperature.

• True

• False

TRUE OR FALSE. The greater the enzyme concentration, the lesser the reaction rate.

• True

• False

This graph shows the enzyme activity when substrate concentration is increased. What is the reason of this enzyme activity pattern?

• There is no available substrate.

• The active site changes its shape, thus, preventing the substrate from binding.

• High substrate concentration affects the temperature at which enzymes work best.

• Enzymes are all occupied, the incoming substrate molecules must wait for an active empty site.

TRUE OR FALSE. All enzymes have a certain pH range at which they work best.

• True

• False

Why an increased in temperature (up to the optimum temperature) increases the enzyme reaction?

• Because kinetic energy of molecules decreases.

• Because kinetic energy of molecules increases.

• Because denaturation of enzymes occurs.

• Because inhibitors are eliminated at this condition.

In a reaction controlled by an enzyme, which of the following graphs shows the effect of substrate concentration on the rate of the reaction?

• A

• B

• C

• D