AP BIOLOGY

Detailed explanation-1: -Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors). The message carried by a ligand is often relayed through a chain of chemical messengers inside the cell.

Detailed explanation-2: -Among the intracellular signaling proteins are kinases, phosphatases, GTP-binding proteins, and many other proteins with which they interact. At the end of each intracellular signaling pathway are target proteins, which are altered when the pathway is active and change the behavior of the cell.

Detailed explanation-3: -Signals Pass From Protein to Protein Signals most often move through the cell by passing from protein to protein, each protein modifying the next in some way. Collectively, the proteins that relay a signal to its destination make up a signaling pathway. A signaling pathway can have few or many steps.

Detailed explanation-4: -The transfer of information from one cell to another. Cells signal each other by direct contact with each other or by the release of a substance from one cell that is taken up by another cell. Cell-to-cell signaling is important for cells to grow and work normally.