AP BIOLOGY

Detailed explanation-1: -In order to detect a signal (that is, to be a target cell), a neighbor cell must have the right receptor for that signal. When a signaling molecule binds to its receptor, it alters the shape or activity of the receptor, triggering a change inside of the cell.

Detailed explanation-2: -Regardless of the nature of the signal, the target cell responds by means of a specific protein called a receptor, which specifically binds the signal molecule and then initiates a response in the target cell.

Detailed explanation-3: -The initiation of a signaling pathway results in a cellular response to changes in the external environment. This response can take many different forms, including protein synthesis, a change in cell metabolism, cell division and growth, or even cell death.

Detailed explanation-4: -The response of a particular cell to a signal depends on its particular collection of signal receptor proteins, relay proteins, and proteins needed to carry out the response.

Detailed explanation-5: -It is very important that not all cells respond to the same signals. Each receptor is unique to a particular signalling molecule and only a cell that has that particular receptor will be able to receive that message, which works like a key and a keyhole model.