Advanced Placement (AP) Biology Practice Exam

What is the role of autocrine signals?

1. To stimulate neighboring cells.

2. To act on the secreting cell itself.

3. To communicate over long distances.

4. To inhibit local cell activity.

The correct answer is: To act on the secreting cell itself.

Autocrine signals play a crucial role in cellular communication by acting on the secreting cell itself. This means that when a cell produces a signaling molecule, it can bind to receptors on its own surface and initiate a response, effectively allowing it to regulate its own activity, growth, or function. This form of signaling is important in various physiological processes, including immune responses and cellular development, as it allows cells to respond to their own secretions and adjust their behavior accordingly. In contrast to other forms of signaling such as paracrine signalling, where signals affect nearby cells, or endocrine signaling, which involves hormones that act over long distances, autocrine signaling is focused and localized. Understanding this mechanism is essential for grasping how cells maintain homeostasis and coordinate their activities in tissues.