Lipids in Cell Membranes Flashcards
What is a lipid?
A molecule that has a low solubility in water
Example of lipids?
Phospholipids
Fats
Sterols
Some vitamins
What are the functions of lipids?
Sources of energy
Form membranes
Participate in cell signalling
What are the two parts of fatty acids?
Carboxyl group with long hydrocarbon chain
What is albumin?
Carrier of fatty acids
What length of fatty acids can be absorbed into the blood stream?
Short and medium
What are the different classifications of fatty acids in double bonds ratio?
Saturated 16:0
Unsaturated 18:1
Polyunsaturated 20:4
What are double bonds numbered as?
Delta
What are some disorders caused by inherited disorders in lipid pathway?
Gaucher’s
Niemann Pick
Tay-Sachs
What are the three different types of lipids found in membranes?
Glycerophospholipids
Sphingolipids
Cholesterol
What are the different head groups found on phospholipids?
Choline
Ethanolamine
Serine
Inositol
What phospholipid head is important in cell signalling?
Inositol
What core does glycolipids have?
Sphingolipids
What happens to membranes?
Turn spherical because of favourable energy position
Why are membranes important?
Compartmentalisation
Highly selective barriers
Have sensors to response to internal and external conditions
What two type of proteins are found in the fluid mosaic model?
Peripheral and integral
How does the structure of phospholipid effect the fluid mosaic model?
Unsaturated hydrocarbon tend to move fluid and faster than the saturated ones
What is the structure of cholesterol?
Polar head. rigid planar steroid ring with a nonpolar hydrocarbon tail
What happens when cholesterol is present in he membrane?
It stiffens
How is asymmetry generated?
Phospholipid synthesized in ER from fatty acids in the cytosol
Release new phospholipids into the outer leaflet of the ER bilayer
Lipids are then transferred to other side by flippases
How does the new membrane reach the plasma membrane?
Synthesized in ER then sent to Golgi
Transported by vesicles along to plasma membrane by motor proteins
Then budding and pinching to join plasma membrane
What are the function of lipid rafts?
Lots of glycoproteins close together for vesicle trafficking and cell signalling
What are the different types of membrane proteins?
Transmembrane
Membrane associated
Lipid-linked
Protein attached
Example of membrane associated proteins
Pleckstrin homology domains
100 amino acid region found in many proteins that binds to certain types of phospholipids
Example of lipid-linked protein
GPI- anchors
Glycosylphosphatidylinositol
Example of protein-attached proteins
Beta 2 adrenergic receptor with G protein signalling
Used for signal transduction
Mediates flight or fight response
