BIO130 Chapter 18

plasma membrane

When activated, part of the receptor migrates from the ________ to the nucleus, where it regulates the transcription of specific genes.

GPCRs

________ activate trimeric GTP- binding proteins called G proteins; these act as molecular switches, transmitting the signal onward for a short period before switching themselves off by hydrolyzing their bound GTP to GDP.

IP3

________ opens Ca2+ channels in the membrane of the endoplasmic reticulum, releasing a flood of free Ca2+ ions into the cytosol.

Cells

________ in multicellular organisms communicate through a large variety of extracellular chemical signals.

RTKs

Some ________ stimulate cell growth and cell survival by activating PI 3- kinase, which phosphorylates specific inositol phospholipids in the cytosolic leaflet of the plasma membrane lipid bilayer.

receptor protein

Each ________ recognizes a particular signal molecule.

extracellular signal molecule

For a(n) ________ to influence a target cell it must interact with a receptor protein on or in a target cell.

cell surface

Plants, like animals, use enzyme- coupled ________ receptors to recognize the extracellular signal molecules that control their growth and development; these receptors often act by relieving the transcriptional repression of specific genes.

G

________ proteins directly regulate ion channels or enzymes in the plasma membrane.

GPCRs

________ and enzyme- coupled receptors respond to extracellular signals by activating one or more intracellular signaling pathways, which, in turn, activate effector proteins that alter the behavior of the cell.

There are three main classes of cell-surface receptors

(1) ion-channel-coupled receptors, (2) G-protein-coupled receptors (GPCRs), and (3) enzyme-coupled receptors