Unit 2 - Membrane Structure/Lipids - Feb 22 Flashcards
Lipid Bilayer
structural basis for virtually all cellular membranes
Fluid-Mosaic Model depicts
integral membrane proteins floating around, ALL cellular membranes have LOTS of proteins in them
Carbohydrate Chains
modify proteins (glycoproteins) (& some lipids-glycolipids) of the plasma membrane on the extracellular side
Lipid Bilayers are selectively-
permeable - size and charge affect the rate of diffusion across a membrane
Molecules from high permeability to low permeability
- Hydrophobic molecules (O2, CO2, N2)
- Small uncharged polar molecules (H2O)
- Large uncharged polar molecules (glucose, sucrose)
- Ions (Cl-, K+, Na+)
Phospholipid Polar Group (aka head group)
most chemically variable portion and determine unique functions to the lipid
Phospholipid fatty acid tails
can vary by their length and how many kinks (C-C double bonds) they have
3 Parts of Phospholipid Structure
Polar Group/Head consists of
-Phosphate Group
-Glycerol
-hydrophilic
Fatty Acid Chain
-hydrophobic
Amphipathic
having a hydrophilic and hydrophobic part
Liposome
a lipid bilayer sphere
Micelles
a spherical structure formed by a single layer of lipids
Saturated vs Unsaturated Fatty Acid H-C Tails
Saturated: hydrocarbons completely packed with hydrogen and have no C=C double bonds
Unsaturated: missing some hydrogens and have some C=C bonds (kink in chain)
No unsaturated fatty acids = _ permeability
vs many unsaturated fatty acids = _ permeability
lower; higher
Cells regulate their membranes by adjusting
the lipid content of membranes
Higher/lower temperature = _ fluidity
more; less
