What is a cell membrane?
- Surrounds the cell to form a barrier
What are the functions of a cell membrane?
- Form a boundary
- Form a barrier
- Transportation
- Selective permeability
What is the fluid mosaic model?
The fluid mosaic model is used to describe the structure and functions of cell membranes.
Describe how the fluidity of cell membranes is affected.
- influenced by the number of double bonds present in cholesterol.
Explain lateral diffusion.
- Rapid diffusion of orientated lipids and globular proteins
What is transverse diffusion?
- spontaneous rotation of lipids from one face of the cell membrane to the other
(very slow)
Describe how cholesterol disrupts fatty acyl chains
- cholesterol disrupts the interactions between fatty acyl chains.
How do phospholipid interactions affect the cell membrane?
- The interactions may concentrate within specific regions of the membrane
- Moderation of membrane fluidity
What do cell membranes consist of?
- Proteins
- Lipids
What are Beta Strands?
- Channel Proteins in the cell membrane
How are Beta strands bonded?
Hydrogen bonds
What do Beta strands do?
- Curl up to creates pores (Porin)
How thick is the cell membrane?
- 2 molecules thick
60-100 (funny A with a circle above it)
Where are Alpha helices found?
- Embedded in the cell membrane
Describe the structure of a phospholipid bilayer
- 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.
Where are integral proteins found?
In the hydrocarbon region of fatty acids in the bilayer
What are Alpha Helices and Beta strands?
Integral proteins
What are peripheral proteins?
Proteins that are attached to the surface of the membrane which bind by interacting with the polar heads of lipids
Where is Prostaglandin H2 Synthase found?
- Bound to the outer membrane by alpha helices
however this is classed as integral as it is partially embedded
