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The Cell MembraneThe Cell Membrane
FOS 3Infectious Disease Unit
FOS 3Infectious Disease Unit
Composition of Cell Membrane
Composition of Cell Membrane
Cell Membranes are NOT all identical, but have FOUR common parts: Lipid Bilayer Transmembrane Protein
Network of supporting fibers
Glycoproteins
Cell Membranes are NOT all identical, but have FOUR common parts: Lipid Bilayer Transmembrane Protein
Network of supporting fibers
Glycoproteins
Lipid Foundation- Phospholipid BilayerLipid Foundation-
Phospholipid BilayerConsist of a:
Glycerol backbone
2 Fatty Acid tails (nonpolar/
hydrophobic)Phosphate Head (polar/hydrophilic)
Consist of a:Glycerol backbone
2 Fatty Acid tails (nonpolar/
hydrophobic)Phosphate Head (polar/hydrophilic)
Lipid Foundation- Phospholipids
Lipid Foundation- Phospholipids
Fatty Acid side is NONPOLARNonsoluble in water
Phosphate side is POLARSoluble in water
Fatty Acid side is NONPOLARNonsoluble in water
Phosphate side is POLARSoluble in water
Lipid BilayerLipid Bilayer
Creates barrier to water soluble molecules
Lipid bilayer is fluid, yet stable.
Creates barrier to water soluble molecules
Lipid bilayer is fluid, yet stable.
Fluid Mosaic ModelFluid Mosaic Model
History of the Fluid
Mosaic Model
History of the Fluid
Mosaic Model
If you want more information of this go
to:http://www1.umn.edu/ships/9-2/membrane.htm
If you want more information of this go
to:http://www1.umn.edu/ships/9-2/membrane.htm
Controls the fluidity of the Cell MembraneControls the fluidity of the Cell Membrane
TemperatureLength of tails and kinks in tails
Cholesterol
TemperatureLength of tails and kinks in tails
Cholesterol
Cholesterol in Cell Membrane
Cholesterol in Cell Membrane
The phospholipid bilayer also contains cholesterol molecules. This gives the layer greater strength, more flexibility, less fluid and less permeable to ions and monosaccharides.
The phospholipid bilayer also contains cholesterol molecules. This gives the layer greater strength, more flexibility, less fluid and less permeable to ions and monosaccharides.
How do things get through if there is a
barrier?
How do things get through if there is a
barrier?Simple diffusion.Through “kinks” in the fatty acid tailsClosely aligned tails have C-C (single bonds)
C=C (double/triple bonds) cause “kinks”
Simple diffusion.Through “kinks” in the fatty acid tailsClosely aligned tails have C-C (single bonds)
C=C (double/triple bonds) cause “kinks”
Protein Functions in the Membrane
Protein Functions in the Membrane
Transmembrane ID MarkersReceptorsChannelsCarrierCytoskeleton attachment and support
Transmembrane ID MarkersReceptorsChannelsCarrierCytoskeleton attachment and support
Transmembrane Proteins extend across lipid
bilayer
Transmembrane Proteins extend across lipid
bilayerThese proteins can have both a polar and a nonpolar region.
These proteins can have both a polar and a nonpolar region.
Proteins act as Cell Identification MarkersProteins act as Cell
Identification MarkersGlycolipids and glycoproteinsCell ID MarkersThis is particularly important in the immune system
Glycolipids and glycoproteinsCell ID MarkersThis is particularly important in the immune system
Major Histocompatibility
Complex
Major Histocompatibility
ComplexUnique to every individualExcept identical twins
Consists of proteins that attach to exterior cells and antigens
Allows T-Cells in the immune system to recognize and attack foreign cells
Glycolipids also differentiate between tissues of same individualA, B, AB and O blood group markers.
Unique to every individualExcept identical twins
Consists of proteins that attach to exterior cells and antigens
Allows T-Cells in the immune system to recognize and attack foreign cells
Glycolipids also differentiate between tissues of same individualA, B, AB and O blood group markers.
Cell Surface ReceptorsCell Surface Receptors
Channel ProteinsChannel Proteins
Carrier ProteinsCarrier Proteins
They do not extend through the membrane
They bond and drag molecules through the lipid bilayer and release them on the opposite side.
They do not extend through the membrane
They bond and drag molecules through the lipid bilayer and release them on the opposite side.
Proteins used to attach CytoskeletonProteins used to
attach CytoskeletonReceptor proteins help to attach the cytoskeleton inside the cell.
Receptor proteins help to attach the cytoskeleton inside the cell.
Membrane Protein Functions
Membrane Protein Functions
Receptor
Membrane Protein Functions
Membrane Protein Functions
