Membrane Flashcards
Three primary functions of membranes
- keep toxic substances out fo the cell
- contain receptors and channels that allow specific molecules to pass between organelles and between the cell and outside environment
- separate vital metabolic processes conducted within organelles
what are lipids
hydrophobic molecules insoluble in water but soluble in organic solvents
role of phospholipids
major component of cell membranes
cholestrol
dispersed between phospholipids and stops membranes becoming stiff by preventing phospholipids packing together to closely
glycolipids
cell recognition
4 cell membrane protein roles
- structural
- receptors
- transport proteins
- glycoproteins
where are proteins mostly found in a membrane
in the inner mitochondrial membrane
where are lipids most commonly found in a membrane
in the myelin
where are carbohydrates most commonly found in a membrane
RBC
what three things does the aggregation of phospholipids depend on
- length of fatty acid chain
- temperature
- degree of saturation of C=C or C-C bonds
what is the most abundant phospholipid in cell membranes
phosphatidylcholine, choline is bound to the phosphate head of the molecule
What is the structure of phosphatidylethanolamine?
ethanolamine attatched at the phosphate head
structure of phsophatidylethanolamine?
small head group size, easier for proteins to be positioned within the membrane
What does a amino acid serine bound to a phosphate head form?
phosphatidylserine
where are phosphatidylserine found
on the outer membrane surface of dying cells signals macrophages to digest them
what is the least common varient fo phospholipid?
phosphatidylinositol, inositol bound to the phosphate group particularly abundant in the brain
example of a membrane phospholipid that is synthesised from glycerol
sphinomyelins
what is a sphinomyelin formed of?
phosphocholine head group, a sphingosine and a fatty acid
how are glycolipids formed?
lipids with a carbohydrate attatched by a glycosidic bond
which membranes are thicker? Those formed by sphinogomyelin bilayers or glycerophospholipids ?
Sphinomyelin bilayers
