Final answer:
The molecule that relays messages from a cell to induce a cellular response is a signaling molecule, also known as a ligand. These ligands can be hormones, proteins, or ions, and their binding to specific receptors on target cells triggers various signaling pathways that result in the intended cellular response. The process involves reception, signal transduction, and the cellular response.
Step-by-step explanation:
The molecule that relays messages from a cell to help induce a cellular response is known as a signaling molecule or ligand. These molecules are produced by signaling cells and upon binding to their specific receptors on the target cells, they initiate a chain of events that leads to the desired response within those cells. Ligands can be diverse, ranging from small proteins to ions like calcium.
Different types of cellular signaling include paracrine, endocrine, autocrine, and direct signaling through gap junctions. In paracrine signaling, the ligands act on nearby cells, whereas in endocrine signaling, hormones are transported through the bloodstream to distant target cells. Autocrine signals affect the cells that produce them or nearby cells of the same type, and direct signaling via gap junctions allows the passage of signaling molecules between adjacent cells.
The process of cellular signaling generally involves three stages: reception of the signal by the receptor, signal transduction where the reception of an extracellular ligand leads to an intracellular signal, and the cellular response. A well-studied example of this process is when the hormone epinephrine binds to its target cells, causing them to convert glycogen to glucose, providing energy for the body in response to stress or exercise.