Membrane Physiology Flashcards
The cell membrane is made up of what kinds of molecules?
Phospholipids and associated proteins - About 47% and 50% (3% carbohydrates)
The phospholipid bilayer is formed by
two leaflets, where the phospholipids are arranged with hydrophobic fatty acid tails in the centre, and the polar, hydrophilic ends facing outwards towards the extracellular and intracellular aqueous environments
What other lipid molecule is intercalated in the bilayer?
Cholesterol
What is the concept of membrane asymmetry?
The two leaflets of the PL bilayer are composed of different phospholipids, and associated with different proteins and carbohydrates (EC).
What is the concept of membrane fluidity and why is it important?
The phospholipids are not fixed - they have lateral movement, creating a fluid structure. Membrane fluidity allows exocytosis, endocytosis and membrane synthesis.
What factors affect membrane fluidity?
Temperature, amount of cholesterol, and degree of FA saturation
What kinds of molecules can diffuse across the cell membrane?
Small molecules and lipid-soluble molecules
What is a lipid raft?
A subdomain of the plasma membrane containing higher concentrations of cholesterol and PLs with longer FA tails, which house proteins
Membranes have two broad types of proteins
1) Integral (transmembrane) proteins
2) Peripheral proteins (which are loosely i.e. non-covalently attached to IC or EC side of membrane)
What are the types of integral proteins?
Channels Carrier proteins Enzymes Cytoskeleton-ECM Linkers Receptors
What are some of the functions of peripheral proteins?
Cytoskeleton components
Second messenger system
