Membrane Structure Flashcards
membrane lipids include _
glycerophospholipids, cholesterol, and sphingolipids
biological membrane key properties
two-dimensional fluid and low permeability to water-soluble molecules and ions
low solubility is key to _
ATP generation, synaptic transmission, senses
cell membrane composition
lipids (42%), proteins (55%), cholesterol (3%)
triacylglycerol vs. glycerolphospholipids
fatty acids are hydrophobic but glycerolphospholipids have a polar head group
glycerol phospholipids
have a polar head group and two hydrophobic fatty acid tails –> leads to lipid bilayer
phosphatidylcholine is most abundant in _
mitochondrion and ER
phosphatidylcholine is least abundant in _
myelin and RBC membrane
phosphatidylserine
low amounts in most membranes
phosphatidylethanolamine is most abundant in _
mitochondrion
general structure of glycerophospholipids
glycerol backbone + saturated fatty acid tail + unsaturated fatty acid tail + polar head group
sphingolipid structure
sphingosine back bone + fatty acid + polar head group
four major phospholipids in cell membranes
phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, sphingomyelin
phosphatidylinositols
not abundant but important for creating DAG and IP3 for cell signaling and assigning membrane identities
DAG
activated PKC
IP3
releases intracellular Ca+2 stores
membrane identities
different PI’s in different stages of endosome to signal which molecules are going to fuse
glycolipids are most abundant in _
myelin (in brain)
cholesterol is most abundant in _
liver PM, RBC PM, and myelin
lateral diffusion
very rapid
unsaturation _
increases fluidity
cholesterol _
decreases fluidity
floppase
transports from inside to outside
flippase
transports from outside to inside
