Cell Membranes Flashcards
1
Q
What is a cell membrane?
A
- Surrounds the cell to form a barrier
2
Q
What are the functions of a cell membrane?
A
- Form a boundary
- Form a barrier
- Transportation
- Selective permeability
3
Q
What is the fluid mosaic model?
A
The fluid mosaic model is used to describe the structure and functions of cell membranes.
4
Q
Describe how the fluidity of cell membranes is affected.
A
- influenced by the number of double bonds present in cholesterol.
5
Q
Explain lateral diffusion.
A
- Rapid diffusion of orientated lipids and globular proteins
6
Q
What is transverse diffusion?
A
- spontaneous rotation of lipids from one face of the cell membrane to the other
(very slow)
7
Q
Describe how cholesterol disrupts fatty acyl chains
A
- cholesterol disrupts the interactions between fatty acyl chains.
8
Q
How do phospholipid interactions affect the cell membrane?
A
- The interactions may concentrate within specific regions of the membrane
- Moderation of membrane fluidity
9
Q
What do cell membranes consist of?
A
- Proteins
- Lipids
10
Q
What are Beta Strands?
A
- Channel Proteins in the cell membrane
11
Q
How are Beta strands bonded?
A
Hydrogen bonds
12
Q
What do Beta strands do?
A
- Curl up to creates pores (Porin)
13
Q
How thick is the cell membrane?
A
- 2 molecules thick
60-100 (funny A with a circle above it)
14
Q
Where are Alpha helices found?
A
- Embedded in the cell membrane
15
Q
Describe the structure of a phospholipid bilayer
A
- Fatty acids which have a Hydrophilic head and hydrophobic tail attached to a sugar.
- The sugar is then attached to a phosphate which is then attached to an alcohol.
