Chapter 15: Cell Signaling

Animations

The following animations are available for this chapter:

15.1 Signaling by Secreted Molecules In endocrine signaling, hormones act on distant target cells; in paracrine signaling, a molecule released from a cell acts on nearby targets; and in autocrine signaling, a cell produces a signaling molecule to which it also responds.
15.2 Signal Transduction The largest family of cell surface receptors transmits signals inside the cell by activating G proteins, which bind GTP and then activate effector proteins.
15.3 Signal Amplification In a signal transduction cascade, each enzyme activated at a stage in the cascade may activate 100 molecules of the next enzyme, quickly amplifying the response to the receptor-bound ligand.

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