Cell Membrane Flashcards
Where is the hydrophilic region of the membrane?
Phosphates i.e. Outer layer.
Where is the hydrophobic region of the membrane?
Fatty acids i.e. Inner layer.
Define integral membrane proteins.
Have hydrophobic regions of amino acids that penetrate it entirely cross the phospholipid bilayer.
Define transmembrane proteins.
Have a specific orientation showings different faces on the two sides of the membrane.
Define peripheral membrane proteins.
Lack hydrophobic regions and are not embedded in layer.
Define glycolipid.
A carbohydrate bound lipid.
Define glycoproteins.
Carbohydrates covalently bonded to proteins.
Name the three types of cell junctions found in animals.
- Tight junctions
- Desmosomes
- Gap junctions.
Define tight junctions.
Link adjacent epithelial cells.
Functions:
•restricts migration of membrane proteins and phospholipids from one region of cell to another.
•Prevents substances from moving though intercellular space.
Defoe Desmosomes.
Hold adjacent cells together by making use of adhesion proteins.
Define gap junctions.
Connections that facilitate the communication between cells. Made of specialised protein channels called connexons (made of proteins called connexins).
Define facilitated diffusion.
When substances must travel through proteins during diffusion in order to enter cell.
Define diffusion.
The process of random movement toward the state of equilibrium.
How does the lipid solubility of a molecule effect the rate of its diffusion?
As lipid solubility increases so does the rate of diffusion.
Define osmosis.
The diffusion of water across membranes.
