AAMC FL Practice Exam

What is the function of an agonist in biological systems?

1. To block receptor responses

2. To inhibit the action of neurotransmitters

3. To stimulate a reaction by binding to a receptor

4. To create an inactive signal at the receptor

The correct answer is: To stimulate a reaction by binding to a receptor

An agonist functions by binding to a receptor in biological systems and stimulating a physiological response. When an agonist attaches to its specific receptor, it mimics the action of a naturally occurring substance, such as a hormone or neurotransmitter, activating the receptor and leading to a specific biological effect. This can involve a variety of responses, including changes in cell signaling pathways, activation of enzymes, or modulation of ion channel activity, ultimately influencing the behavior of the target cells or tissues. Understanding the role of agonists is critical in the fields of pharmacology and biochemistry, as they are often used in drug development to enhance or induce desired effects in the body, such as pain relief or improved heart function. This contrasts with other agents, like antagonists, which block receptor responses, inhibit neurotransmitter actions, or create inactive signals, all of which serve to diminish or prevent biological reactions.