Membranes Lecture Flashcards

Flashcards based on lecture notes about membranes.

Plasma Membrane

Asymmetric fluid mosaic with a hydrophobic core and hydrophilic sur

Integral Proteins

Proteins embedded in the membrane, often transmembrane.

Peripheral Proteins

Proteins loosely bound to the membrane.

Glycoproteins and Glycolipids

Carbohydrate chains found on the extracellular surface of the membrane.

Phospholipid Bilayer

The polar head groups face outward, and fatty acid chains are internal.

Phosphoglycerides

Lipids with varied polar head groups.

Sphingolipids

Lipids including sphingomyelin and glycolipids.

Outer Leaflet

Contains more phosphatidylcholine and sphingomyelin, also glycolipids.

Inner Leaflet

Contains more phosphatidylserine and phosphatidylethanolamine.

Unsaturated Fatty Acids

Fatty acids with cis double bonds that create kinks.

Flip-flop

Movement of a phospholipid from one leaflet to the other.

Flippases

Proteins that contribute to the synthesis of asymmetric membranes.

Cholesterol

Stiffens the membrane near the sterol ring but leaves the middle fluid.

Integral Membrane Proteins

Embedded in the bilayer and can only be removed with detergents; often transmembrane.

Peripheral Proteins

Not embedded in the membrane; can be solubilized with aqueous solvents.

Membrane Proteins Functions

Proteins that function as transporters, anchors, receptors, or enzymes.

Transmembrane Protein Segment

Segment with an alpha-helical structure composed of amino acids with nonpolar side chains.

Non-cytosolic (Outer) Surface

Oligosaccharide chains and disulfide bonds are on this surface.

Multi-pass Transmembrane Proteins

Proteins that pass through the membrane multiple times, with hydrophobic portions as alpha-helices or beta-pleated sheets.

Seven-spanning Domain Receptors

Hormone receptors linked to G proteins, having seven spanning domains.

Partially Embedded Proteins

Proteins embedded in the membrane but not spanning it entirely, like cyclooxygenase-1.

Lipid Anchors

Lipids attached to proteins after synthesis, anchoring them to the membrane.

Examples of Lipid Anchors

Fatty acids like myristate or palmitate and poly-prenyl groups like farnesyl.

Peripheral Proteins

Bound to the membrane by non-covalent interactions with other proteins.

Protein Translocation

Specific intracellular signals result in modification of cytosolic proteins which then associate with the membrane

Caveolae and Rafts

Membrane domains rich in cholesterol and sphingolipids.

Ordered Lipid State

Association of cholesterol leads to ordered lipid state domains.

Movement of membrane proteins

visualization of movement of membrane proteins by forming heterokaryons.

Restricted Protein Movement

Proteins linked to peripheral cytoplasmic proteins of the cytoskeleton, limiting lateral movement.

Tight Junctions

Restrict movement of plasma membrane proteins to specific membrane domains.

FRAP (Fluorescence Recovery After Photobleaching)

visualization of movement of proteins within a membrane

Glycocalyx

Cell coat rich in carbohydrates on glycoproteins and glycolipids.

Extracellular Matrix

Associated with the glycocalyx, made up of proteins, glycoproteins, and proteoglycans.