Membrane Structure and Function

A comprehensive set of flashcards covering key terms and definitions related to membrane structure, function, and signaling pathways.

Fluidity of fatty acids

Enhanced by short chain length and unsaturation due to cis bonds.

Phospholipids

Major class of membrane lipids composed of fatty acids, an attachment site, a phosphate, and an alcohol.

Cholesterol

Lipid based on steroid nucleus, comprised of four linked hydrocarbon rings, that disrupts tight packing of fatty acid chains.

Amphipathic

Molecules that contain both hydrophobic and hydrophilic moieties, as seen in membrane lipids.

Micelle

Globular structure with polar heads on the outside and hydrophobic tails on the inside.

Lipid bilayer

Two sheets of lipids forming a permeability barrier, with hydrophilic heads facing the aqueous environment.

Integral membrane proteins

Proteins that interact extensively with hydrocarbon chains of membrane lipids, spanning the lipid bilayer.

Peripheral membrane proteins

Proteins that are bound to the membrane primarily by electrostatic and hydrogen-bond interactions.

Transmembrane helices prediction

Can be predicted by the hydropathy index which reflects the free-energy change for spans of amino acids.

Hydropathy plot

Graph plotting the hydropathy index against amino acid sequences, used to identify potential membrane-spanning helices.

Na+ - K+ ATPase

An enzyme that catalyzes the active transport of sodium and potassium ions across the membrane by hydrolyzing ATP.

ABC transporter

Transporters that include ATP-binding cassettes, facilitating molecule export in eukaryotes and import in prokaryotes.

Secondary active transport

Transport process where the movement of one molecule up a concentration gradient is coupled to the favorable flow of another.

Action potential

Electrical signal produced by the flow of ions across the plasma membrane of a neuron.

Ligand-gated ion channels

Channels that open in response to the binding of specific molecules, such as neurotransmitters.

Aquaporins

Channels that facilitate the rapid and specific movement of water across membranes.

Facilitated diffusion

Transport of polar molecules across a membrane down their concentration gradient, utilizing transport proteins.

G protein-coupled receptors

Seven-transmembrane-helix receptors that signal through G proteins when activated by ligands.

Calmodulin

A calcium-binding protein involved in various cellular processes, responding to changes in intracellular calcium levels.

Insulin signaling pathway

Pathway initiated by insulin that promotes glucose transport and metabolic regulation.