Lecture 1 Flashcards
diffusion
net movement of molecule down concentration graident
requirements for diffusion through plasma membrane
small, no charge, non polar (aka hydrophobic, lipophilic)
4 factors influencing diffusion rate
magnitude of concentration, permeability, temperature, surface area
hypokalemia and effect on concentration gradient?
- low K+
- greater gradient pulling K+ out of cell
passive vs active transport
- passive: no energy required, moves down concentration gradient
- active: ATP energy required
simple diffusion
no channels, nonpolar moelcules go down concentration gradient
facilitated diffusion
transporter protein has binding site and changes conformation moving molecule down gradient
ex: GLUT
channel factiliated difusion
no binding site, ions pass through channel down gradient
carrier mediated transport definition
transmembrane protein wiht specific binding site
ex: GLUT
3 requirements of carrier mediated transport
1) specificity of bind site
2) competition (ex galactose and glucose)
3) saturation - there exists a transport maximum
primary active transport
- ATP directly used by protein to transport up gradient
- ex: Na+/K+, Na+ out and K+ in
secondary active transport
- ATP indirectly used
- Na+ goes down gradient into cell and brings glucose along
cotransport aka symport
- secondary active transport where both molecules move in the same direction
countertransport aka antiport
- secondary active transport where molecules move in opposite direction
absorption/reabsorption in GI and kidney tract - 3 examples of transport
1) primary active transport Na+/K+ channel moves Na+ to blod
2) facilitated diffusion of glucose from cell to blood
3) secondary active transport of glucose into cell using Na+ graident
