A Level Biology Practice Exam

What is the role of an inhibitor in enzyme reactions?

1. To enhance the rate of the reaction

2. To prevent or reduce the rate of enzyme activity

3. To stabilize the enzyme structure

4. To transport substrates to the enzyme

The correct answer is: To prevent or reduce the rate of enzyme activity

The role of an inhibitor in enzyme reactions is indeed to prevent or reduce the rate of enzyme activity. Inhibitors can bind to the enzyme or the enzyme-substrate complex, resulting in decreased enzymatic function. This can occur in several ways, such as competitive inhibition, where the inhibitor competes with the substrate for the active site, or non-competitive inhibition, where the inhibitor binds to a different part of the enzyme, altering its shape and functionality. Inhibitors are crucial for regulating metabolic pathways in biological systems, ensuring that enzyme activity is finely tuned based on cellular needs. This regulation can affect overall metabolic processes, allowing cells to respond to changing environments or internal conditions effectively.