control IC pH Flashcards
what is pH?
log to the base 10 [H+] its a logarithmic scale so a small change in ph is big H+ change
what happens if pH goes from 7.1 to 7.4
[H+] = halved
what happens if pH from 7.8 to 7.5
[H+] = doubles
what at as a buffer in the cell ?
carboxyl group on proteins
difference between acidification and alkalisation
acidification - add H+
alkinisation - remove H+
Give examples of how intracellular pH can be measured.
using micro electrodes if the cell big enough - V1 is normal and V2 has a H+ gel so measure the Vm of everything but H+ so V1-V2 = H+ Vm = pH
or
in small cells use fluroscent indicator and light is proportional to pH
what is an Ionophore
substance that transports ions across a lipid membrane
what is a buffer and examples
minimises change in pH
COOH if pH is high it donates H+
NH2 if ph low it mops up H+ so NH3
Acid extrusion - what is, an example of an exchanger
reverses change of pH change
Na+/H+ excahnger caleed NHE1
if pH more acidic than stepping wanted it switches on and H+ transported out and Na+ in
what can affect the NHE1
calcium calmodulin changes the stepping so activatd more at acidic pH
What is acid loading, example of exchanger
Cl- into cell and HCO3- out of cell when too alkaline and example is AE3
What can inhibit the AE3
stilebene derivatives drugs inhibit the exchanger AE3 which does acid loading
when does pH reach its resting state
when acid loading and acid extrusion are equal and there is no net influx of ions
where can the AE1 be found
AE1 – predominantly in red blood cells, some in kidney
