AP Biology : Understand the effect of environment of the enzyme

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understand The Effect Of Environment Of The Enzyme

Which of the following factors has an effect on the rate at which enzymes catalyze a reaction?

Possible Answers:

pH of environment

Temperature of environment

All of these factors have an effect on the rate at which enzymes catalyze a reaction

Concentration of substrate and enzyme

Correct answer:

All of these factors have an effect on the rate at which enzymes catalyze a reaction

Explanation:

The temperature and pH of the environment, as well as the concentration of the substrate and enzyme, all affect the rate at which an enzyme catalyzes a reaction. As a result, enzymes have optimal conditions in which they can work at peak efficiency.

Example Question #2 : Understand The Effect Of Environment Of The Enzyme

Consider the reaction:

This reaction is catalyzed by an enzyme called carbonic anhydrase. Which of the following will result from increasing the concentration of carbonic anhydrase?

Possible Answers:

It will increase the equilibrium constant

It will cause reaction to go slower

It will have no effect on the equilibrium constant

It will decrease the equilibrium constant

Correct answer:

It will have no effect on the equilibrium constant

Explanation:

Enzymes are catalysts that help a reaction proceed faster. Increasing the concentration of carbonic anhydrase will not cause the reaction to go slower. Recall that catalysts (in this case carbonic anhydrase) do not alter the equilibrium of a reaction. They simply speed up the process so that equilibrium can be achieved more quickly. Increasing or decreasing the equilibrium constant means that there is a change in the equilibrium state of the reaction.

The equilibrium constant can only be affected by temperature changes or pressure changes, if there is a gas involved in the reaction. Catalysts affect the rate constant, which is dependent on activation energy. By decreasing activation energy, catalysts can increase the rate constant and allow a reaction to proceed faster.

Example Question #3 : Understand The Effect Of Environment Of The Enzyme

In non-physiological reactions an increase in temperature will increase the reaction rate; however, in physiological reactions there is an optimum temperature at which an enzyme operates. Increasing the temperature beyond this will not increase enzyme activity or reaction rate. What explains this phenomenon?

Possible Answers:

Increasing the temperature will increase the activation energy

High temperatures will change the shape and functionality of proteins

Increasing the temperature will decrease the activation energy

Heat will shift the equilibrium to the left, favoring the reactant side

Correct answer:

High temperatures will change the shape and functionality of proteins

Explanation:

There is an optimum temperature at which an enzyme is most effective. Decreasing or increasing the temperature from the optimum will lead to denaturation of proteins, which will affect their functionality. Most protein structure is dependent on non-covalent intermolecular forces, such as hydrogen bonding and hydrophobic interactions. Heat can disrupt these forces, causing the protein to lose its structure, which leads to a loss of functionality.

You can eliminate the answer choices about activation energy because changing temperature will have no effect on the activation energy. Adding heat could shift the equilibrium to the right or left, depending on whether the reaction is exothermic or endothermic.

Example Question #4 : Understand The Effect Of Environment Of The Enzyme

Which of the following characteristics affects the function of an enzyme?

Possible Answers:

All of these

Temperature

Substrate concentration

None of these

pH

Correct answer:

All of these

Explanation:

Temperature, pH, and substrate concentration all affect the function of an enzyme; therefore, the correct answer is all of these.

Example Question #5 : Understand The Effect Of Environment Of The Enzyme

Which of the following statements about enzymes is correct?

Possible Answers:

They are consumed in the reaction

They function under a narrow pH range

They are used to create ATP

They always require a coenzyme

They are polymers of carbohydrates

Correct answer:

They function under a narrow pH range

Explanation:

The correct answer to this question is they function under a narrow pH range.

Enzymes do indeed function under a narrow pH range. A narrow pH range is needed because enzymes speed up reactions by lowering the activation energy and in order to do this very specific conditions must be met. Coenzymes are not always needed and they are certainly not consumed in a reaction. Enzymes also are proteins so they are polymers of amino acids, not carbohydrates. Also enzymes have no part in the creation of ATP.

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