BSC2010: Chapter 9 Vocabulary Words

cell communication

the process through which cells can detect and respond to signals in their environment

signal

an agent that can influence the properties of cells

receptor

protein that detects a signal molecule and performs an action in response

cellular response

adaptation at the cellular level that involves a cell responding to signals in its environment

cell-to-cell communication

a form of cell communication that occurs between two different cells

direct intercellular signaling

signals pass through a cell junction from the cytosol of one cell to adjacent cells

contact-dependent signaling

membrane-bound signals bind to receptors on adjacent cells

autocrine signaling

cells respond to signaling substances that they themselves secrete

paracrine signaling

Signal released from a cell has an effect on neighboring cells.

endocrine signaling

Specialized cells release hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body.

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

receptor activation

The "turning on" of a receptor, which often occurs when a signaling molecule binds to a receptor on a responding cell.

signal transduction

the transmission of molecular signals from a cell's exterior to its interior

signal transduction pathway

A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response.

cell surface receptors

receptors found in the plasma membrane

enzyme-linked receptors

transmembrane proteins that bind a signal and directly catalyze a reaction inside the cell

protein kinases

transfer phosphates from ATP to protein, a process called phosphorylation

G-protein coupled receptors

A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. Also called a G protein-linked receptor.

G proteins

Proteins that are activated by exchanging bound GDP for bound GTP (and thus also known as GTP-binding proteins).

ligand-gated ion channel

A transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions.

intracellular receptors

receptors located inside the cell rather than on its cell membrane

Receptor Tyrosine Kinases (RTKs)

Best known group of enzyme-linked receptors

-Steps:

1) Hormone binds to RTK

2) RTK forms a dimer and is phosphorylated by ATP

3) Proteins build a bridge between Ras and RTK

4) Ras triggers phosphorylation of another protein

5) Phosphorylation cascade amplifies

growth factor

broad group of proteins that stimulate cell division

protein kinase cascade

a pathway in which one protein kinase activates the next, and so on

second messenger

A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signal received by a signal receptor protein.

adenylyl cyclase

An enzyme that converts ATP to cyclic AMP in response to a chemical signal.

cyclic AMP (cAMP)

Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons.

Protein Kinase A (PKA)

a protein kinase activated by the second messenger cAMP

phosphodiesterase

enzyme that degrades cAMP, producing AMP, to terminate signaling

protein phosphatases

An enzyme that removes phosphate groups from proteins, often functioning to reverse the effect of a protein kinase.