Chapter 6.1.1 (Exam 1) The Fluid Mosaic Model Flashcards
Biological Membranes Are Lipid-Protein Bilayers
What is the fluid mosaic model?
The fluid mosaic model describes the general structure of biological membranes
What are biological membranes composed of?
Proteins
Phospholipids
Cholesterol
What role does cholesterol play in a biological membrane?
Membrane integrity and fluidity
How do phospholipids in a biological membrane vary?
Fatty acid chain length
Degree of saturation
Phosphate groups
The membrane interior is somewhat fluid, allowing lateral movement of molecules. What does this membrane fluidity depend on?
Lipid composition
Temperature
How does membrane fluidity depend on lipid composition?
Cholesterol and long chain saturated fatty acids pack tightly –> less-fluid membrane
Unsaturated, shorter-chain fatty acids have bends (and less cholesterol) and pack less densely –> more fluid membrane
How does membrane fluidity depend on temperature?
Membrane fluidity increases as temperature goes up and vice versa
Membranes also contain proteins. What are the three types of membrane proteins?
Integral
Peripheral
Anchored
What does the number of proteins in a membrane depend on?
The function of the membrane
What are integral membrane proteins?
Integral membrane proteins are at least partly embedded in the bilayer
What is one specific type of integral membrane protein?
Transmembrane proteins extend all the way through the phospholipid bilayer, with one or more transmembrane domains
The domains on the inner and outer sides can have more transmembrane domains
What are peripheral membrane proteins?
Peripheral membrane proteins lack hydrophobic portions and do not penetrate the bilayer
What are anchored membrane proteins?
Anchored membrane proteins are covalently attached to fatty acids or other lipids
