Acid Base Balance

• What is a base defined as?

  A molecule that accepts a hydrogen ion
• How do strong acids behave in solution?

  They dissociate completely in solution
• What is an acid defined as?

  A substance that donates a proton
• How do weak acids behave in solution?

  They ionize incompletely in solution
• What does the Acid Dissociation Constant (Ka) represent?

  The ratio of dissociated to undissociated particles
• What is the formula for the Acid Dissociation Constant (Ka)?

  $K_a =$$\frac{[H^+][A^-]}{[HA]}$
• What does a low pKa indicate about an acid?

  It is a strong acid
• What is the relationship between pKa and acid strength?

  Strong acids have low pKa values
• What is the formula for pKa?

  $pK_a =$$-\log_{10}(K_a)$
• What does pH measure?

  The acidity of a solution
• What is the formula for calculating pH?

  $pH =$$-\log_{10}([H^+])$
• What does a high concentration of hydrogen ions indicate about a solution's pH?

  It has a low pH value
• What does a high concentration of hydroxide ions indicate about a solution's pH?

  It has a high pH value
• What does "p" in pH stand for?

  Negative logarithm
• What is the isoelectric point (pI)?

  The pH at which a molecule is neutral
• How is the isoelectric point (pI) calculated?

  Average of pKa1 and pKa2
• If pKa1 is 2.34 and pKa2 is 9.60, what is the pI?

  $5.97$
• What does the Henderson-Hasselbalch equation relate?

  pH, pKa, acid, and conjugate base concentrations
• When is pH equal to pKa in the Henderson-Hasselbalch equation?

  When the acid is half ionized
• What is a buffer?

  A solution that resists pH changes
• What determines buffer capacity?

  The concentrations of acid and conjugate base
• When is a buffer most effective?

  When pH equals pKa
• What happens when a strong base is added to a buffer?

  The weak acid donates H+ to neutralize it
• What happens when a strong acid is added to a buffer?

  The weak base reacts with H+ to form HA
• What is the normal plasma pH?

  7.4
• What is acidosis?

  pH below 7.35
• What is alkalosis?

  pH above 7.45
• What can a significant drop in pH interfere with?

  Protein (enzyme) functions
• What is the first line of defense for plasma pH regulation?

  Body buffer system
• What is the second line of defense for plasma pH regulation?

  Respiratory regulation
• What is the third line of defense for plasma pH regulation?

  Renal regulation
• What is the bicarbonate buffer system's role?

  It is the most important buffer in plasma
• What percentage of buffering capacity in plasma does the bicarbonate buffer system account for?

  65%
• What is the normal bicarbonate (HCO3-) level in plasma?

  24 mmol/L
• What is the normal carbonic acid (H2CO3) level in plasma?

  1.2 mmol/L
• What is the pKa for carbonic acid (H2CO3)?

  6.1
• What ratio is maintained for blood pH at 7.4 in the bicarbonate buffer system?

  20:1 (HCO3: H2CO3)
• What is the phosphate buffer system primarily used for?

  It is mainly an intracellular buffer
• What is the role of the protein buffer system?

  It depends on the pKa of side chains
• What is the most effective group in the protein buffer system?

  Histidine imidazole group