AP BIOLOGY

Detailed explanation-1: -The process by which a cell responds to substances outside the cell through signaling molecules found on the surface of and inside the cell.

Detailed explanation-2: -Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events, most commonly protein phosphorylation catalyzed by protein kinases, which ultimately results in a cellular response.

Detailed explanation-3: -A signal-transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response. Signal transduction pathways convert signals on a cell’s surface into cellular responses.