Transport Flashcards
Osmosis
Diffusion of water.
Bulk flow
Response of liquids or gases to differential pressures.
Passive Transport
Simple diffusion through lipid bilayer.
Through spanning proteins.
Does not take energy.
Ligand Gated Channel
Ligand binds to protein to open the channel.
Mechanically gated
Sense membrane pressure to open with increases pressure.
Facilitated diffusion
Uniporter carrier.
Net flux of glucose down gradient.
Conformational change allows the molecule through.
Stoichiometric ratio because each conformational change takes a certain number with it.
Active Transport
Requires an energy source.
Primary active transport
Uses ATP to go against gradient.
This is a direct use of ATP
Secondary active transport
Energy source is the concentration gradient.
Co-transporter (Na,Glucose Co-transporter) Na goes down the gradient and takes glucose with it.
Secondary active transport exchangers
Energy source is the bicarbonate gradient.
Important in respiration.
Anion exchanger 1: flux of Cl and HCO3 in opposite direction. HCO3 always goes down the gradient.
Endocytosis
Engulf extra cellular particles to take them into the cell.
Phagocytosis-immune system.
Also a way of removing spanning proteins from the cell membrane.
Exocytosis
Release of substances from a cell by merging vesicles with cell membrane.
How you get messengers out.
Also a way of inserting membrane proteins into the cell.
Glucose transporter 4
Found in fat and muscle cells.
The number of receptor is dictated by the amount of insulin. More insulin causes exocytosis while less insulin causes endocytosis.
Aquaporin 2
Controls water flow.
Found in epithelial including the ducts of the kidney.
Exocytosis is controlled by v2r receptor which binds vasopressin to activate and favor exocytosis.
