Biology in Focus Chapter 5.6 - Cell Communication

Paracrine Signaling

A form of cell-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior or differentiation of those cells. (Cell targets a nearby cell)

Synaptic Signaling

Occurs in animal nervous system in which an electrical signal moving along nerve cell triggers the secretion of neurotransmitter molecules carrying a chemical signal. The molecules diffuse across the synapse, triggering a response in the target cell.

Endocrine Signaling

Specialized cells release hormone molecules, which travel via the circulatory system to other aprts of the body, where they reach target cells that can recognize and respond to the hormones. (A cell targets a distant cell through the bloodstream)

Autrocrine Signaling

Cell targets itself.

Reception

Target cell's detection of a signlaing molecule coming from outside the cell.

Transduction

A series of steps that converts that signal to a form that can bring about a specific cellular response. Requires a sequence of changes in a series of different molecules.

Signal Transduction Pathway

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

Response

The change in a specific cellular activity brought about by a transduced signal from outside the cell.

Ligand

A molecule that binds specifically to another molecule, usually a larger one.

G Protein

A GTP-binding protein that relays signals from a plasma membrane signal receptor to other signal transduction proteins inside the cell.

G Protein-Coupled Receptor (GPCR)

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

Ligand-Gated Ion Channel

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

Transcription Factors

A regulatory protein that binds to DNA and affects transcription of specific genes.

Protein Kinase

An enzyme that transfers phosphate groups from ATP to a protein; thus phosphorylating the protein.

Protein Phosphatases

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

Phosphorylation

The transferring of phosphoryl group from a donor to the recipient molecule.

Dephosphorylation

The process of removing phosphate groups from an organic compound.

Second Messengers

A small, nonprotein, water-soluable molecule or ion, such as a calcium ion or cylic AMP, that relays a singal to a cell's interior in response to a signaling molecule bound by a signal receptor protein.

Cyclic AMP (cAMP)

A ring-shaped molecule made from ATP that is a common intracellular signlaing molecule in eukaryotic cells. It is also a regulator of some bacterial operons.

Local Regulators

Messenger molecules secreted by signaling cell.

Earl W Sutherland

Explained how animal hormone epinephrine stimulates the breakdown of the storage polysaccharide glycogen in livers cells and skeletal muscle cells.

Tyrosine Kinase

Receptor proteins with enzymatic activity. Several pathways. An enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions.

Quorum Sensing

Communication among microbes that triggers group response once particular population densities are reached.

Amplification

Increasing of signal > response.