Lec 9/11 Flashcards
phospholipid structure
- polar head on surface, hydiphilic
- Fatty acyl tails inward, hydrophobic, form weak noncovalent bonds
- amphipathic(lipophilic/hydrophobic and hydrophilic)
unit membrane
- inner leaflet(inner surface Protoplasmic or P-face)
- outer leaflet(outer surface Ectoplasmic or E-face)
- 1:1 phospholipid to protein ratio
what are proteins on inner leaflet?
- phosphatidylserine(PS)
- phosphatidylethanolamine(PE)
what are proteins on outer leaflet?
- phosphatidylcholine(PC)
- phosphatidylglycerol(PG)
what is apoptosis?
- programmed cell death
- stimulus or signal to undergo programmed cell death (DNA fragmentation~180bp, followed by morphological changes to cell/membranes)
signs of apoptosis
cell shrinkage, fragmentation, engulfment/degradation, no inflammation, limited tissue damage
signs of necrosis
cell swelling, organelle rupture, membrane rupture, tissue damage, inflammation
what happen in a healthy cell
PS asymmetry, active “flippase” process, slight negative charge
what happen in an apoptosis cell?
PS asymmetry lost, lippase activity lower, PS externalized–> “eat me” signal
annexin assay
- protein binds to - charged phospholipid (PS)
- protein is couples to fluorophore (fluorescent)
- fluorescence can be visualized using microscopy
- apoptotic cells will be labled and glow or fluorescent
EX of amphipathic molecules
- phospholipids(fatty acyl tails increase membrane fluidity)
- glycolipids
- cholesterol(decreases membrane fluidity)
protein membrane components
- integral/transmembrane proteins (span membrane, ion channel, transport protein), multipass(signaling), more on P-face
- periferal proteins(mainly cytoplasmic face)
fluid mosaic model
- come mobility of integral proteins
- limited in polarized cells(apical, basolateral)-related to cellular function
glycocalyx-cell coat
- up to 50nm thick
- stains w/ lectins, Alcain blue (Ingrain blue)or ruthenium red
glycocalyx-carbohydrate chains
may be linked to transmembrane proteins, phospholipids