Acid-Base Buffering Flashcards
(15 cards)
What is the purpose of a buffer
Help maintain the acid-base balance for physiological functioning
At 25 degrees Celsius, the concentration of pure water
55.5M
Normal blood pH
7.4
Define acids and bases
Acid is a proton donor; base is a proton acceptor
Define Ka (ionization/dissociation constant) of a an acid
The tendency of the acid to lose a proton and form a conjugate base
Explain the relationship between acid strength and pKa
The stronger the acid, the lower the pKa
Explain short term relief of GERD
Tums (CaCO3) neutralizes the acid in the stomach, end product is CO2 and water; comes out as a burp
Explain long term relief of GERD
Omeprazole is a proton pump inhibitor
Explain the neutralization zone on titration curve- meaning and what it looks like
This is when the acid is getting neutralized and is a flat zone on the curve
How do you tell whether an acid is weak or strong on its titration curve?
Where it’s neutralization (flat) zone is
What is special about the midpoint of a titration curve?
At the midpoint, the pKa is equal to the pH; [HA] = [A-]
What determines if a buffer is efficient or not?
The buffering zone needs to be closer to the physiological pH in order to be an efficient biological buffer
Explain Protein Buffer System
Proteins embedded with histidine side chains can act as weak acids or bases, the Histidine side chain pKa is 6.8 which is near 7.4
Explain Phosphate Buffer System; and where does it occur?
Occurs in cytoplasm; pKa of 6.8
Explain Bicarbonate Buffer system
Normally, bicarbonate has a pKa of 3.8 but carbonic anhydrase catalyzes a reaction with CO2, this has a pKa of 6.1
