Unit 2 - Plasma Membranes Flashcards
Compartmentalisation is
The formation of separate membrane bound areas in a cell
Compartmentalisation is needed as
Metabolism includes many and often incompatible reactions. So this enables specific environments for cellular reactions to happen
The plasma membrane is
The cell surface membrane that separates the cell from its external environment
What are membranes formed from
A phospholipid belayer
Describe the fluid mosaic model
Fluid - The phospholipids are free to move within the layer, which gives the membrane flexibility
Mosaic - the proteins embedded in the bilayer are all shapes and sizes and positions
Glycolipids in a bilayer…
Act as a recognition site eg for cholera toxins
Glycoproteins are
Branching, carbohydrate portion of a protein which acts as a recognition site for chemicals like hormones
Cholesterol function
Stability and flexibility
and regulates fluidity of membranes
Intrinsic proteins are
Embedded through both layers of the membrane (whole span of bilayer)
They have a hydrophobic r group externally, which interact with the also hydrophobic core of membrane - keeping it in place
Two types of intrinsic proteins are
Carrier, channel
What do channel proteins do?
Provide a hydrophilic channel, for PASSIVE movement
Water being polar cannot otherwise travel through the membrane
What do carrier proteins dp?
Have an important role in passive and active transport
Are glycoproteins intrinsic or extrinsic
intrinsic
what do glycoproteins have attached to them
carbohydrate chains of varying lengths and shapes
what are two things glycoproteins do
role in cell adhesion, receptors for chemical signals
