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27 terms

plasma membrane lipid bilayer

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plasma membrane
encloses the cell, defines the cell boundaries, maintains the essential difference between the cytosol and the extracellular environment
other membranes
nucleus, endoplasmic recticulum, golgi apparatus, mitochondra, lysosomes, peroxisomes
lipid bilayer
provides the basic structure of the membrane, serves as a relatively impermeable barrier
50%
lipid molecules are __ of most animal cell membrane
amphiphilic
hydrophilic and hydrophobic
phospholipid
most abundant membrane lipids, have a polar head group and two hydrocarbon tails
unsaturated
one phospholipid tail has cis double bonds
saturated
one phospholipid tail does not have double bonds
phosphoglycerides
the main phospholipids in most animal cell membranes are
phosphoglycerides
have three carbon glycerol backbone, two long chain fatty acids, third carbon attached to phosphate group
phosphate group heads
Phosphatidylethanolamine, Phosphatidylserine
Phosphatidylcholine
phosphatidylethanolamine
Phosphatidylserine
Phosphatidylcholine
sphingomyelin
sphingosine
sphingomyelin
built from sphingosine, long acyl chain with an amino group and two hydroxyl groups at one end of the molecule
cholesterol
polar head group, rigid steroid ring structure, nonpolar hydrocarbon tail
glycolipids
sugar containing lipids, located on the non-cytosolic monolayer of the lipid bilayer, made from sphingosine, sugars addded in the lumen of golgi, cell recognition process
galactocerebroside
galactose sugar attached
Gm1 ganglioside
5 sugars attached
sialic acid
six carbon cyclic ring attached
lateral diffusion
___rarely flip flop, flexion rotation occurs
lipid componets of bilayer
convert extracellular signals into intracellular signals, cytosolic side of the bilayer is negatively charged
phospholipases
activated by extracellular signals to cleave specific phospholipid molecules serving as signal mediators
phosphatidylserine
signals next cell to phagocytose and digest the dead cells, phospholipid translocator is inactivated,
scramblase
transfers phospholipids nonspecifically in both directions between the two monolayers is activated