Biocell Lecture 3 Flashcards
Where are glycolipids found?
They are found exclusively in the non cytoplasmic (exoplasmic) part of the lipid bilayer
Where are lipids with choline found?
Lipids with choline are found in the outer half of the lipid bilayer.( exoplasmic)
Where are phospholipids molecules found?
Phospholipidmolecutes that contain a terminal primary amino group are found in the inner half (cytosolic layer)
What does fluidity of a lipid bilayer depend on?
Temperature and composition
What does fluidity of a bilayer increase with?
Short fatty acid chains and unsaturated chains
When can proteins move laterally in a bilayerV
When they are not attached
The plasma membrane is weak alone. What does it have to reinforce its structure?
Two components. Glycocalyx and the cytoskeleton.
Glycocalyx:
50nm thick
External part of the cell and consists of mainly carbohydrates. This forms the glycocalyx or cell coat.
It’s function is to protect the cell surface from mechanical or chemical damages
Oligosaccharide chains help mediate cell to cell adhesion events and also mediates cell recognition events.
What does cytosolic side of the lipid bilayer mean? What proteins are included?
Cytosolic means the oner half of the lipid bilayer.
Proteins included are actin ankirin and spectrum.
What does the cytoskeleton do!
It reinforces the membranes of eukaryotic cells. Determines the cell shape, involved in cell surface activities. It is 5-9nm thick
Functions of plasma membrane
Transport
Cell signalling
Cellular adhesion
Lipid bilayer provides the most basic structure of membrane. Relatively impermeable barrier to water soluble molecules.
Protein molecules dissolved in lipid bilayer mediate most other functions of cell membrane.
Explain cell junctions
Cells in tissues are linked to either each other or to the extra cellular matrix by specialised sites called JUNCTIONS.
3 types: - anchoring
Communicating
Occluding
THEY HAVE A SPECIAL FEATURE CALLED CELLULAR ADHESIAN MOLECULES. CAMS.
These are transmembrane proteins that realise the connection.
