Cell Surface Membrane Flashcards
What does the cell surface membrane consist of
A phospholipid bi layer Intrinsic and extrinsic protein Cholesterol Glycoproteins Glycolipids
How is the cell surface membrane described
By the fluid mosaic model
Function of the cell surface membrane
- Site of chemical reactions
- Site of cell communication
- A barrier between the cell and its outside environment
What is the phospholipid bi layer
Is a double layer of phospholipids, with the hydrophilic head facing out and the hydrophobic tail facing inwards. The membrane is fluid. Its width is 7nm.
What are intrinsic proteins
Are proteins that are embedded in the membrane. These include channel and carrier proteins as well as glycoproteins.
What are glycoproteins
Are proteins with an attached carbohydrate chain. They are receptors as they have a specific shape that is complementary to the trigger molecule.
Role of glycoproteins
- They act as a receptor for cell signalling
- They stabilise the membrane by forming hydrogen bonds with water.
- Act as a binding site for hormones, drugs and neurotransmitters
Role of cholesterol
It regulates fluidity of the membrane by stopping phospholipid clumping together and reduces permeability.
What is cell signalling
A complex system of intracellular communication which may cause a response in the cell, or to communicate between cells
Role of channel proteins
Allow passive movement of polar molecules.
What are extrinsic protein
Proteins that are outside the cell
What are glycolipids
Are lipids with carbohydrate chains attached. They are antigens.
How do molecules pass through the membrane
Non polar molecules diffuse across while polar molecules require proteins
Factors that effect membrane structure
Temperature- gain me KE so there is more movement and more fluidity
Solvent- solvents can dissolve membranes distrusting cells for example alcohol
