Unit 4 - Cell Communication and Cell Cycle (copy)

Cell Communication

The ability of a cell to communicate with its environment and itself, essential for maintaining homeostasis and survival.

Ligand

A signaling molecule that binds to a receptor protein.

Receptor Protein

A protein that binds to a ligand to initiate a signaling pathway; can be on the cell membrane or inside the cell.

Direct Cell-to-Cell Signaling

Communication between cells that involves direct physical contact, facilitated by structures such as gap junctions or plasmodesmata.

Paracrine Signaling

A form of signaling where a cell releases a signal that induces changes in nearby cells, diffusing over short distances.

Endocrine Signaling

A type of signaling that involves the release of hormones into the extracellular fluid, which travel long distances to target cells.

Synaptic Signaling

Communication between a neuron and its target cell through the release of neurotransmitters at a chemical synapse.

Autocrine Signaling

A signaling process where a cell sends signals to itself by binding to its own receptors.

Signal Transduction Pathway

The process through which a ligand-bound receptor relays a message through a series of reactions to elicit a cellular response.

Phosphorylation

The addition of a phosphate group to a protein, which can activate or deactivate the protein and is catalyzed by kinases.

Kinases

Enzymes that catalyze the phosphorylation of specific proteins in the cell.

Phosphatases

Enzymes that catalyze the removal of phosphate groups from proteins.

Cellular Response

The change in a cell’s behavior or characteristics resulting from a signal transduction pathway.