Cell Membrane structure Flashcards
What are the 3 major membrane lipids?
Phospholipids, glycolipids, sterols
What are the phospholipid molecules
1 molecule glycerol, 2 molecules fatty acid, 1 phosphate group
What are phosphatidylcholine?
Is a source of choline
Why is phosphatidylcholine function
In the brain, it acts as a precursor to acetylcholine helping brain function
In the liver, phosphatidylcholine is an ingredient in the bile complex that allows fat emulsification
What are phosphatidyethanolamine
Phospholipids that are building blocks of cell membrane
What are functions of phosphatidylethanoalamine
It converts to phosphatidylcholine,
Helps assembly or membrane proteins
May be needed to orient enzymes in the inner membrane
What is phosphtidylinositol
It is present in cell types but mostly im brain tissu
What are the functions of phosphatidylserine
It is found mostly in the cells of the brain and nerves and reinforces the stability and integrity of cell membrane
How are ceramides formed from spinghosine
Fatty acid + amino group of the spinghosine = ceramides
How is spinghomyelin formed
Ceramide+phosphocholine
What are functions of sphingolipids
Transmit signals and are important in cell recognition and protects the cell layer by forming a mechanically stable and chemically resistant plasma lipid bilayer
What is cholesterol
A membrane of steroids that are weakly amphipathic
How does cholesterol increase membrane packing
Interacts with phospholipid fatty acid chain which changes membrane fluidity
Makes the membrane and lipid layer more stable
Decreases its permeability to water soluble molecules
What do the physical characteristics of lipid layer depend on
Width of bilayer which is determined by the length of fatty acid
Nature or phosphate heads
What are physiological significances of
Lipid bilayer
Forms a base where other molecules attach to
It allows fat soluble lipid and small uncharged molecules to freely pass through
Big uncharged molecules and small charged molecules must have special means of transport
It is fluid, allows molecule to change shape while maintaining structural integrity
