L03 - CELL SURFACE MEMBRANE Flashcards
1
Q
What is the purpose of the CSM?
A
- Separates the extracellular and intracellular environments (compartmentalisation)
- Controls which substances are allowed in and out of the cell
- Protects the cell
2
Q
What is compartmentalisation?
A
- Where the CSM maintains a different internal environment to the extracellular environment
3
Q
Describe the structure of the CSM
A
- Phospholipid bilayer - phospholipids and cholesterol
- Embedded proteins
- fluid mosaic
- selectively permeable
4
Q
Amphipathic definition
A
Phospholipids have both a hydrophilic and hydrophobic region
5
Q
What are the names of the 4 different phospholipid types in the bilayer?
A
- Phosphatidylchlorine
- Phosphatidylserine
-Phosphatidylethanolamine
-Sphingomyelin
6
Q
Types of lipids in the bilayer
A
- Phospholipids
- Intracellular signal transduction lipids - rapidly generated and rapidly generate signals; rapidly degraded when signal has gone
7
Q
What two things does cholesterol effect, and what one thing does it not effect?
A
Effects:
- Permeability
- Rigidity
Does not effect:
- Fluidity
8
Q
What factors effect simple diffusion? (3)
A
- Concentration gradient
- Charge and how hydrophobic molecule is
- Size of the molecule
9
Q
Which molecules are membranes highly impermeable to?
A
IONS
10
Q
Which two types of proteins are involved with facilitated diffusion?
A
- Channel proteins - discriminate based on size and charge
- Uniporter carrier proteins - has binding site for specific solutes highly selective
11
Q
How do uniporter carrier proteins work? (3 steps)
A
- Protein open on the outside of the cell and allows solutes to bind inside channel
- Solutes fill binding space
- Channel has conformational change and release molecules on other side of membrane
12
Q
Electrochemical gradient definition
A
Combination of both the concentration gradient and the membrane potential
