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Flashcards in Control of intracellular pH Deck (11)
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How do you measure pH using electrodes

Two electrodes are used
Electrode 1 is a normal microelectrode measuring Vm
Electrode 2 has a small amount of proline - a H+ sensitive resin in the tip
This measures the Vm for everything apart from proton movement
1-2 gives the change in voltage due to protons which is = to the change in pH
Calibration of electrodes using pH standards
y = mx + c
y = Voltage, X = pH


How do you measure pH using fluorescent indicators

Cell is loaded with an inactive form of a charged molecule
Naturally occurring enzymes cleave the inactive form
Indicator excited with specific wavelength of light and the amount of light emitted at a second wavelength is measured
Fluorescence is pH dependant


Define a buffer

A system that modulates the effects of acid or alkali load by reversibly consuming or releasing protons


What channel is involved in acid loading and how does it work

Cl-/HCO3- exchanger
Inward movement of chloride ions and the removal of bicarbonate from inside the cell - this leaves behind a proton inside the cell causing acidification


What chemical inhibits AE1



What channel is involved in acid extrusion

Na/H exchanger - Relies on the function of Na/KATPase to create a concentration gradient for Na to move into the cell.


What is allosteric modification present in NHE1

Protons other than the one being transported bind to the channel at an allosteric site and produce a conformational change in the channel making it more active than before


How do CaM and PKC modulate NHE1

They change the set point of the channel making the exchanger more active at more alkali levels
They bind on the long C-terminus


How many transmembrane domains does NHE1 have



What is a role of NHE1

Found on the basolateral membrane of epithelial cells - linked to cell vol control


When is resting pH achieved

When the rate of acid extrusion is equal to that of acid loading