Question

Question: If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?

1. Additional substrate will be formed.
2. The reaction will change from endergonic to exergonic.
3. The free energy of the system will change.
4. Nothing; the reaction will stay at equilibrium.

Short answer

1. The option "Additional substrate will be formed" is false.
2. The option "The reaction will change from endergonic to exergonic" is false.
3. The option "The free energy of the system will change" is false.
4. The option "Nothing; the reaction will stay at equilibrium" is true.

Step-by-step solution

Meaning of enzymes

Enzymes are biocatalysts produced by living organisms. They are known as agents of life as they accelerate chemical reactions. These function in aqueous solution under mild pH and temperature conditions.

Explanation of option (A)

Substrates are molecules that bind to the enzymes' active site during catalysis and lead to the formation of the product.

Thus, the addition of enzymes would not lead to the formation of the excess substrate. This is because substrates for enzymes are added at the beginning of the reaction along with enzymes to obtain the desired product.

Therefore, the given option is false.

Explanation of option (B)

Endergonic reactions are catalyzed by enzymes by linking them to exergonic processes. Enzymes accelerate the rate of reaction but adding enzymes will not change the reaction from endergonic to exergonic.

Therefore, the given option is false.

Explanation of option (C)

Free energy refers to the amount of energy associated with a system.The free energy change of a reaction is denoted as ΔG. Enzymes lower the activation energy and speed up the reaction, but they do not affect the free energy of a reaction.

Thus, adding an enzyme would not change the system's free energy as it remains the same.

Therefore, the given option is false.

Explanation of option (D)

At equilibrium of a chemical reaction, the substrate concentration is equal to the concentration of the product. This means the rate of forward and backward reactions would be the same.However, enzymes cannot affect the equilibrium state of a reaction.

The equilibrium only depends on the initial concentration of substrates, and adding enzymes would not affect the equilibrium state of the reaction.

Thus, the reaction will stay at equilibrium.

Therefore, the given option is true.