Cell Membranes and Lupus

Lupus

autoimmune disease associated with antibodies against nuclear proteins, alternates between flare-ups and periods of remission`

lipid bilayer (phosopholipids, cholesterol) and proteins

membrane composition:

hydrophobic fatty acyl chain tail, hydrophilic glycerol/phosphate/alcohol head

phospholipid structure

amphipathic

molecule that contains both hydrophobic and hydrophilic regions

peripheral, lipid-anchored, integral/transmembrane)

proteins associated with lipid bilayer

fluid mosaic model

describes the way proteins are embedded in semi-fluid lipid bilayer

4 nm, 1-100nm, 10 microns

cell membrane thickness, protein size, cell diameter

transmembrane helices

non-polar side groups face out towards fatty acid tails, leaving polar backbone protected, found in integral transmembrane proteins

transport barrier

lipid bilayer forms a ___ ___

1. compartmentalizes/localizes function

2. regulates transport

3. binds ligands by receptors and transduces signals

4. cell-cell/substrate binding through adhesion receptors

membrane functions

unsaturated

lipid molecule that contains one or more double bonds between its carbon atoms, loosely packed

omega

nth carbon after which you find the first double-bond

cholesterol, low, high

___ keeps membranes fluid at __ temps, reduces fluidity at __ temps

lipid rafts

cholesterol-rich nanodomains in plasma membrane

glycolipids, have carbohydrate (sugar) attached to them, act as antennae for signaling and structural shield

found on surface of all plasma membranes