Transport Systems Flashcards
Name 3 classes of transport systems
Uniport
Symport
Antiport
Differences between Uni, Sym and anti
Uni - One
Sym - Two in same direction
Anti - Two but in opposite directions
Examples for
1) Channel
2) Uniporter
3) Antiporter
4) Primary active transport
5) Secondary active transport
1) Aquaporins
2) Glut 1 transporter
3) Chloride- Bicarbonate exchanger
4) Sodium Potassium ATPase
5) Sodium Glucose Symporter
Channels mediate facilitated diffusion of substances down their what?
Concentration or electrochemical gradient
Channels discriminate substances based on what
Size and charge of the solute
The solute in channels, interacts with what on its way through?
With amino acid residues lining the tunnel on its way through
Aquaporins are what
Hydrophilic transmembrane channels for the passage of water
Uniporters do what
Accelerate a reaction that is already thermodynamically favoured
What are the 3 main features that distinguish uniport transport from passive diffusion?
1) Rate of facilitated diffusion is much higher than passive
2) Transport is specific
3) Transport occurs via a limited number of uniporters as they are saturable
Rate of uniport transport shows same characteristics of what
M&M kinetics
A bicarbonate transporter is an antiporter that does not change what?
The electrochemical potential across the membrane
Antiporter is what
Anion exchange protein (AE1 or Band 3)
What is active transport?
Movement of susbtances against their electrochemical gradient
Difference between primary and secondary active transport?
Primary - Movement of one ion
Secondary - Couples the movement of one ion uphill alongside another ion downhill
What does Na+/K+ ATPase do
Maintains intracellular Na+ K+ concentrations
