Advanced Placement (AP) Biology Practice Exam

What is the function of a chemical inhibitor in relation to enzymes?

1. To increase enzyme activity

2. To stabilize enzyme structure

3. To enhance the reaction rate

4. To decrease enzyme activity

The correct answer is: To decrease enzyme activity

The function of a chemical inhibitor in relation to enzymes is to decrease enzyme activity. Chemical inhibitors work by binding to an enzyme and interfering with its ability to catalyze reactions. There are several ways this can occur, such as competing with the substrate for the active site or binding to another part of the enzyme to change its shape (a process known as allosteric inhibition). By doing so, they effectively lower the rate at which the enzyme can convert substrates into products, hence decreasing overall enzyme activity. Effective enzyme regulation is important in various biological processes, as it ensures that metabolic pathways can be controlled according to the needs of the cell. For example, inhibitors can regulate the activity of enzymes in response to changes in substrate concentration, product levels, or other metabolic signals. This regulatory mechanism allows for fine-tuning of metabolic processes and can also be important in drug design, where inhibitors can be used therapeutically to target specific enzymes involved in diseases.