large charged unable to cross membrane. Use proteins as channels or transporters. Integral membrane proteins
Channels vs transporters?
channels move many ions at once... transporters one at a time
How does a channel work?
polar residues on inside let water and ions pass
how does a transporter work?
binds to molecule on one side of membrane and undergoes conformational change to release on opposite side of membrane
whats a uniporter?
transports one substance 1 direction
what is cotransporter?
2 different substances. symporter in same direction, antiporter in opposite
examples off small molecules for simple diffusion
o2, n2, ether, ethanol, benzene, co2, h20
what is cystinuria
autosomal recssive, defect in transport system responsible for uptake of cystine. makes kidney stones and renal cholic (waves in tummy)
autosomal recessive. defect in transporter for non-polar and neutral amino acids. Fail to thrive, tremor, eye problems
Ligand gated channel
neurotransmitter or hormone binds and opens it. Ions go down concentration gradient. NT or hormone leaves and channel closes
Voltage gated ion channel
found in neurons. opens when depolarization (more positive inside cell)
protien assisted, energy dependent, against concentration gradient
What makes active transport work energy wise
ATP hydrolysis makes conformational change
Na/K ATPase how many of each
3 Na out of cell, 2K in
secondary active transport
against gradient, energy dependent protein assisted.
where does secondary active transport get energy?
Not ATP hydrolysis. Like Na and Glucose. Na into cell on gradient through diffusion, glucose comes in with it. primary transport to reset Na to outside cell
Na Ca exchanger. Keeps low Ca in cells. 3 Na in, 1 Ca out. Uses energy stored in Na gradient
Bringing in Dietary Monosaccharides
works by facilitated diffusion and active transport.
Galactose and glucose in through apical membrane and what ion?
Glucose and galactose and fructose through basal side which transporter?
What does Glut 5 transport through apical side?
What are cardiotonic drugs?
Ouabain and digoxin act as cardiotonic (contraction inducing drugs)
How do cardiotonic drugs work?
Inhibit Na/K atpase, more Na inside cell as a result. No more concentration gradient to flow down. NCX slows down and Ca builds up. More Ca inside cell and SR, stronger excitation contraction of heart muscle with each action potential
What is CF?
Autosomal recessive, lungs, pancreas, intestines. Thick mucous in lungs as cells have more Cl and salt, Na enters cells because of negative potential in cells water follows. Lots of bacteria, scarring.
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