Lecture 2 Flashcards
Do animal cells have a lipid bilayer T/F
Ture
What do the lipid bilayers contain
Peripheral and integral proteins
What is the % Lipid:Protein Ratio
This ratio varies in the composition of membranes according to its function
The Composition of Cell Surfaces (are related to what?)
Is related to their permeability
What is greater in permeability integument or epithelial cells
The permeaof epithelial (ex. Gills) is greater than the integument (ex. Skin)
What does the low permeability of most integuments depend on (what is it composed of)
A thin layer of keratin, lipids, or wax
Are cellular membranes heterogeneous in composition? T/F
True
Are inner and outer layers of the membrane distinct? T/F
True
What are Lipid Rafts? (what do they accumulate? Are they rigid or fluid? What type of proteins do they recruit?)
- Regions that accumulate cholesterol and glycolipids
- These regions are more rigid
- They recruit specific proteins that are involved in signaling pathways
Where do Lipid Rafts Readily Move?
Through the plasma membrane
Cold Temperature impact on Membrane Fluidity
Make the phospholipid bilayer more and more rigid (gel state)
Warm Temperature impact on Membrane Fluidity
Make the phospholipid bilayer more fluid (liquid crystalline state)
Physiological Temperature effect of Membrane Fluidity
Cell membranse are in the liquid crystalline state
Membrane Lipids: Phospholipid (what type of molecules are they? What does the fluidity depend on)
- Are amphipathic molecules
- Membrane Fluidity depends in part of the level of saturation state of nonpolare tails
Interaction of Cholesterol with the Fatty Acid Tails
The more cholesterol the more disruption in the interaction between fatty acid tails, increasing membrane fluidity
