1Describe the Lipid Bilayer:
All lipid molecules in the membrane are amphipathic.
2The phospholipid bilayer is most impermeable to what?
Charged molecules like ions, large polar molecules.
3What passes easily through a phospholipid bilayer?
Small nonpolar molecules
4Why are uncharged polar heads of the phospholipid bilayer favorable in its environment?
They can form electrostatic interactions/Hbonds with water molecules.
5What is Lateral Diffusion?
Lipids move around within the bilayer (lateral diffusion) - lipids move from one side to another, intracellular to extracellular. Also called "flip-flop".
6Lipid molecules spontaneously aggregate to bury their hydrophobic tails. What are the 2 different forms?
Spherical micelles (tails inward) cone shaped. Bilayers (tails sandwiched between hydrophillic heads) cylinder shaped.
7How are new phospholipids synthesized? What is the importance of new phospholipids?
Enzymes on the cytosolic layer of the ER. Newly made phospholipids help replace and create a new lipid bilyer.
8What family of enzymes help create a new lipid bilayer:
Phospholipids translocators, They catalyze the "flip-flop" of phospholipids.
9The _____ of a membrane depends on its _____ and _____.
Fluidity, Composition, Temperature. Fluidity is a property of the membrane that has to be closely regulated due to membrane transport.
10The temperature at which membranes solidify depend on...
- Length of hydrocarbon fatty acid.
- Number of double bonds
- Shorter bonds or ones with double bonds have a lower phase transition or solidify at a lower temperature.
11Do you need saturated or unsaturated hydrocarbon chains for fluid membranes?
Unsaturated
12What other kinds of lipids make up membranes? What
Cholesterol, enhances the permeability barrier.
13What kind of phospholipid determines what kind of phospholipid is in the membrane?
Phosphatidylcholine
14What phospholipid has a net negative charge?
Phosphatidylserine
15What are the 4 different phospholipids:
Phosphatidylethanolamine, Phosphatidylserine, Phosphatidylcholine, Sphingomyelin
16What is the Lipid Raft?
A thicker region in the PL bilayer. Good for cell signaling, brings receptors togethers, they bring together membrane proteins. Transport protein.
17Explain Transmembrane proteins?
Amphipathic, Single pass tm proteins are Receptors, Multipass tm proteins are Carrier proteins. Composed of Alpha helix
18Peripheral proteins
These proteins support and maintain shape of the membrane
19What kind of charge does the cell carry?
Negative charge inside, positive charge outside.
20What molecules are most permeable to the membrane?
Relatively permeable to non polar molecules.
21Antiport
If 2 solutes are moved in opposite direction
22Simple diffusion
Movement of solutes through lipid bilayer with no aid
23Symport
If 2 solutes are moved in the same direction
24Coupled transport
If one solute is dependent on the transport of the second solute.
25What is more abundant outside the cell?
Sodium
26Explain sodium potassium pump
Sodium wants to go inside the cell because the cell is naturally negative, the sodium potassium pump then pumps the sodium out, and potassium in(ATP hydrolysis). Glucose depends on the sodium concentration gradient. Couple transport.
27What do sodium potassium pumps do?
Drives nutrients transport and regulated cytosilic pH
28What are the ATPases P type, F type, ABC type, V type:
ATP driven pump, Generates ATP, Binds ATP for the transport process, Vacuole pump.
29What causes resistances to drugs?
ABC type transport rids body of drug molecules, the body will continuosly create ABC transport.
30Gap junctions
Links adjacent cells together and allow communication and nutrients to be shared.