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Cell Membrane (plasmalemma)
components
phospholipid bilayer
similar to but missing polar group = triglycerides
three fatty acids + glycerol
storage of energy
main constituent of fats and oil
concise storage of energy
have a polar group at head, fatty acids at tail
interacts with water
fatty acids repelled by water
group together to form membranes in water on their own
two fatty acids + Phosphor
types (additions to phosphor = polar group)
phosphatidylcholine
choline added
phosphatidylserine
serine
phosphatidylinositol
inositol
phosphatidylethanolamine
ethanolamine
bilayer
two layers from grouped phopholipids
fatty acids of each layer point to each other
heads on one side in cell
heads on other side outside cell
other types of phospholipid
uses something other than glyerol backbone
sphingomyelins
kinks in the faty acids allow for movement in membraneÂ
2 types of fatty acids
saturated
unsaturated
with a kink
from double covalent bonds
cholesterol
used to add strength to membrane
creates additional liquidity by creating more space between phospholipids
only on exterior membranes
plasma membrane layers
exterior
phosphatidylcholine + sphingomyelins
interior
phosphatidylserine + phosphatidylinositol + phosphatidylethanolamine
internal packages (cytolemmas) for export have layers reversed around item to eject from cell
membrane proteins
integral
penetrate membrane
usually in alpha-helix form
functions
cell identity markers
carriers
used as transporters
transport channels
anchors
cell adhesion molecules
enzymes
surface for chemical reactions
peripheral
sits on or in membrane
attaches to either integral proteins or membrane
determines what function cell will perform in its environmentÂ
cytoskeleton = network of internal membrane proteins
Functions
separate
inside
outside
regulates movement of molecules in and out of cell
maintains electrochemical gradient
allows for action-potential / impulses
cell to cell interaction
Qualities
semipermeable
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