Flashcards in Membrane Structure Deck (10):
Molecular Components of a Membrane
Lipids: form 5nm bilayer, prevent hydrophilic diffusion
Proteins: scattered throughout, transporters and signalers
Carbohydrates: extracellular, function in immune, development, protein folding, virus/toxin binding
Dependent on temperature and composition, highly dynamic with lipids switching places 10^7 times/min and diffusing several mm/sec
Parts of a phospholipid
Two hydrophobic fatty acyl chains (16-18 Cs long) attached to a glycerol phosphate backbone via hydroxyl group. Polar head group consists of glycerol, phosphate, and interchangeable group.
Types of phospholipids (4)
Parts of Sphingolipid
Sphingosine pairs with fatty acyl chain via amide linkages to form a ceramide. Ceramides have different head groups for different functions.
Polar head group attached to rigid steroid ring attached to hydrocarbon tail. Intercalates between lipids and decreases fluidity.
Different thicknesses of membranes
Dependent on cholesterol content. Thickness increases with cholesterol content. ER
Negative phospholipids (serine and inositol) usually intracellular.
PhosCholine, Shpingolipids, and glycolipids extracellular
Cholesterol even distribution
Types of membrane associated proteins (3)
Transmembrane: alpha helices, beta sheets, single or multi-pass
Covalent non-trans: anchored cytosolic by amphipathic alpha helix,through covalent attachment to membrane components
Non-covalent: associate w/ membrane through protein-protein interactions