Chapter 2: Water/Acid-base/Buffers/Weak Interactions Flashcards
What is the Henderson-Hasselbach equation? What does it help us understand/calculate?
pH = pKa + log ([A-]/[HA])
Helps understand buffer action and acid-base balance in the blood and tissues. Helps calculate pH given pKa and molar ratio of proton donor and acceptor. Helps calculate pKa given pH and molar ratio of proton donor and acceptor. Helps calculate molar ratio of proton donor and acceptor given pH and pKa.
What are two especially important biological buffer systems and why are they important?
The phosphate and bicarbonate systems. The phosphate buffer system is maximally effective around its pKa of 6.86. It tends to resist change from 5.9 to 7.9. It is therefore an effective buffer in biological fluids; in mammals, for example, extracellular fluids and most cytoplasmic compartments have a pH in the range of 6.9 to 7.4. Blood plasma depends on the bicarbonate buffer system, which involves three reactions.
What is the pH optimum?
A characteristic pH where enzymes show maximal catalytic (physiological) activity. Usually around pH 7
