Cell Communication Flashcards

Flashcards covering vocabulary related to cell communication, signal transduction, and receptors.

Cellular Communication

Allows cells to "talk" to one another and coordinate their activities, often using chemical signals.

Ligand

A signal molecule that binds with a receptor molecule, resulting in a reaction within the cell.

Intracellular Receptors

Receptor molecules located inside the cell, in the cytosol; ligands must be hydrophobic to cross the cell membrane.

Extracellular Receptors

Receptors located on or in the cell membrane; ligands are hydrophilic and bind to receptors on the membrane, causing a chain reaction (signal transduction) inside the cell.

Direct Signaling

Occurs between cells that are in direct contact with one another

Direct Signaling (Mechanism)

Chemicals travel back and forth from one cell to the next via gap junctions or plasmodesmata

Local Signaling

Cells are separated by a short distance

Paracrine Signaling

Chemicals are released by one cell and travel through the extracellular space to bind with other cells; numerous cells can respond to the message.

Synaptic Signaling

Occurs between the tips of nerve cells (neurons) and the cells they connect to; uses neurotransmitters like serotonin, melatonin, dopamine, oxytocin.

Endocrine Signaling

Works well over long distances; chemicals called hormones are released by an organ into the blood and circulate until they bind to receptors on the target organs.

Signal Transduction

A series of steps by which a signal on a cell's surface is converted into a specific response.

Reception

Signal molecule (ligand) binds to a molecule on the membrane (receptor).

Transduction

The message is passed along from one molecule to the next, often involving messengers and secondary messengers.

Response

Machinery of the cell produces some action (e.g., enzymes activate/deactivate, cytoskeleton changes shape, genes activate/deactivate).

Receptor Tyrosine Kinases (RTKs)

Consists of a receptor embedded in the membrane connected to a kinase protein.

Kinase

Enzyme that transfers phosphate groups (phosphorylates or dephosphorylates other molecules).

Function of RTKs

Binding of a single ligand to a single receptor can stimulate many pathways inside the cell; a single signal has many effects

G Protein-Coupled Receptors (GPCRs)

Involve a receptor, a G protein, an adenylyl cyclase (another enzyme), and cAMP.

Functions of GPCRs

60% of medications used today influence G protein pathways

Cyclic AMP (cAMP)

Acts as a secondary messenger and can cause many responses in the cell

Ligand-Gated Ion Channels

Some membrane channels have to be stimulated in order to open and close and allow things to flow across the plasma membrane