Question

Describe and explain the effect of a gradual increase in temperature on an enzyme-controlled reaction. Refer to the lock and key hypothesis.

A) As temperature increases, enzyme activity generally increases until a point (optimal temperature) where it starts to denature. The lock and key hypothesis explains the specificity of enzymes to their substrates.
B) As temperature increases, enzyme activity decreases. The lock and key hypothesis explains the flexibility of enzymes.
C) As temperature increases, enzyme activity remains constant. The lock and key hypothesis doesn't apply.
D) None of the above.

Answer 1

As temperature increases, enzyme-catalyzed reaction rates increase up to an optimum temperature, beyond which the enzymes denature due to structural changes, resulting in a decrease in reaction rate.

Step-by-step explanation:

The effect of a gradual increase in temperature on an enzyme-controlled reaction can be described as follows: initially, as the temperature increases, the rate of the enzyme-catalyzed reaction increases too. This is because the kinetic energy of molecules increases, leading to more frequent and effective collisions between enzymes and substrates. This concept aligns with the lock and key hypothesis, which states that enzymes are highly specific to their substrates, much like a lock is to its key. However, beyond a certain point, known as the optimum temperature, any further increase in temperature starts to degrade the enzyme's structure, leading to denaturation. This structural change reduces the enzyme's activity as it can no longer bind to the substrate effectively, ultimately leading to a decrease in reaction rate.