Neuronal Action Potentials and Protein Transport

These flashcards cover key vocabulary and concepts related to neuronal action potentials and protein transport within cell biology.

Na+ channels

Voltage-gated channels that inactivate rapidly after opening.

Inactivation gate

A structure that blocks the Na+ channel pore during inactivation.

Repolarization

The process of returning the membrane potential to its resting negative value.

K+ channels

Delayed channels that open to restore the cell’s resting potential.

Action potential propagation

The movement of an electrical signal along an axon.

Nodes of Ranvier

The gaps in the myelin sheath where Na+ channels are concentrated.

Saltatory conduction

The process of action potentials jumping from node to node along a myelinated axon.

Transmitter-gated ion channels

Channels that open in response to neurotransmitter binding, altering the postsynaptic membrane potential.

Synaptic cleft

The narrow gap between the presynaptic and postsynaptic cells.

Exocytosis

The process through which neurotransmitters are released into the synaptic cleft.

Calcium influx (Ca2+)

The entry of calcium ions that triggers neurotransmitter release.

Excitatory neurotransmitters

Chemicals that depolarize the postsynaptic membrane, promoting an action potential.

Inhibitory neurotransmitters

Chemicals that make it harder to depolarize the postsynaptic membrane.

Acetylcholine

A neurotransmitter that can have excitatory or inhibitory effects depending on its receptor.

Neuromuscular junction

The synapse between a motor neuron and a muscle cell.

Signal sequence

A peptide sequence that directs the transport of a protein to its correct cellular location.

Endoplasmic Reticulum (ER)

A membrane system involved in protein and lipid synthesis.

Rough ER

Regions of the ER associated with ribosomes engaged in protein synthesis.

Smooth ER

Regions of the ER lacking ribosomes, involved in lipid synthesis.

Vesicular transport

The movement of proteins among organelles using membrane-enclosed vesicles.

Translocators

Membrane proteins that facilitate the transport of molecules into the ER.

Polypeptide chain

A sequence of amino acids that folds into a protein.

SRP (Signal-Recognition Particle)

A complex that guides the ER signal sequence to the ER membrane.

Calcium release channels

Channels in the sarcoplasmic reticulum that release calcium during muscle contraction.

Gated transport

The movement of molecules through nuclear pore complexes between the nucleus and cytosol.

Polyribosome

A cluster of ribosomes translating the same mRNA molecule.

Sec61 complex

A translocator in the ER membrane that allows polypeptides to pass through.

Hydrophobic side chains

Amino acid residues that favorably interact with lipid environments, often in transmembrane proteins.