p.15
Isoelectric Point (pI)
How is the pI calculated for Glycine (Gly)?
pI = (pK1 + pK2) / 2, where pK1 = 2.3 and pK2 = 9.6.
p.25
Phosphate Buffering System
What are the pKa values for the phosphate buffering system?
pKa1 = 2.15, pKa2 = 7.2, pKa3 = 12.4.
p.19
Buffering concept and systems in the body
What are the phosphate and bicarbonate buffering systems in the body?
They are important systems that help maintain the pH balance in the body by resisting changes in pH.
p.30
pH and pKa relationship
What happens to the partial pressure of CO2 in the lungs when holding your breath or breathing into a paper bag?
It increases above normal levels.
p.24
Bicarbonate Buffering System
What is the Chloride Shift?
The movement of chloride ions into the cell as bicarbonate ions move out.
p.27
pH and pKa relationship
What does the Henderson-Hasselbalch equation explain?
How a change in acid or base concentration affects the pH.
p.19
Buffering concept and systems in the body
What is the concept of buffering?
Buffering refers to the ability of a solution to resist changes in pH when an acid or base is added.
p.29
pH and pKa relationship
What is the equation for pH in terms of pKa, [A-] and [HA]?
pH = pKa + log 10 [A-] / [HA]
p.25
Phosphate Buffering System
Why are phosphate species usually paired with other cations?
They are often paired with other cations, often Na+.
p.28
pH and pKa relationship
What is the Henderson-Hasselbalch equation?
pH = pKa + log10 [A-]/[HA]
p.20
Buffering concept and systems in the body
What happens when added OH- reacts with HA in a buffer solution?
It causes a shift to the right in the equilibrium position.
p.12
pH and pKa relationship
How do pH and pKa relate?
When pH > pKa, the species is in the conjugate base (unprotonated) form.
p.30
Buffering concept and systems in the body
How do competitive short-distance runners raise their blood pH before starting?
By hyperventilating for about 30 seconds to remove CO2 from their lungs.
p.24
Bicarbonate Buffering System
How does the Chloride Shift affect the hematocrit levels in venous blood?
It causes venous hematocrit to be approximately 3% higher than arterial hematocrit.
p.7
Strong vs Weak Acids & Bases
What is the chemical equation for the dissociation of a weak base?
MB (aq) + H2O (l) ↔ BH+ (aq) + MOH- (aq)
p.17
pH, pK, pI and K D concepts
What are the pK values for the titration of Lysine (Lys)?
pK1 = 2.2, pK2 = 9.0, pK3 = 10.5.
p.9
K a , pK a , K b & pK b concepts
What does K D represent in the given equation?
The equilibrium constant for the reaction.
p.14
K a , pK a , K b & pK b concepts
What is the term for having more than one pKa value for polyprotic acids?
Polyprotic acids have more than one pKa value.
p.30
pH, pK, pI and K D concepts
How can the partial pressure of CO2 in the lungs be varied rapidly?
By the rate and depth of breathing.
p.29
pH and pKa relationship
What is the equation for pH in terms of pKa, [HCO3-] and [H2CO3]?
pH = pKa + log 10 [HCO3-] / [H2CO3]
p.11
pH, pK, pI and K D concepts
What is the mathematical relationship between hydrogen ion concentration and hydroxide ion concentration in a solution?
[H + ] x [OH - ] = 10^-14
p.25
Phosphate Buffering System
What is the major buffering system for urine and intracellular fluid?
Phosphate Buffering System.
p.25
Phosphate Buffering System
What are the two main phosphate species involved in the buffering system?
Dihydrogen phosphate and Monohydrogen phosphate.
p.24
Bicarbonate Buffering System
What is the role of Band 3 in the Chloride Shift?
It acts as a bicarbonate ion/chloride antiporter.
p.15
pH, pK, pI and K D concepts
What is the definition of pI (isoelectric point)?
The pH at which a molecule carries no net charge.
p.5
Buffering concept and systems in the body
What happens when dilute HCl is added to the acetate buffer?
The impact of pH change is lessened.
p.24
Bicarbonate Buffering System
What happens as a lot of chloride ions move into the cell in venous blood?
It causes water to follow, resulting in swelling of the cell.
p.7
Strong vs Weak Acids & Bases
What is the chemical equation for the dissociation of a weak acid?
MB (aq) + H2O (l) ↔ BH+ (aq) + MOH- (aq)
p.16
pH, pK, pI and K D concepts
how do you calculate PI of an acid vs basic?
<p>acid = pk1+pk2/2 basic =pk2+pk3/2</p>
p.20
Buffering concept and systems in the body
What happens when added H+ reacts with A- in a buffer solution?
It causes a shift to the left in the equilibrium position.
p.15
pH and pKa relationship
Why is the pI relevant for predicting the charge of an amino acid at a given pH?
Because it indicates the pH at which the amino acid carries no net charge.
p.10
K a , pK a , K b & pK b concepts
What does a small K a (or K b) value indicate?
Very little dissociation (very little [Product]).
p.10
pH and pK a relationship
What does a pK a (or pK b) value does not indicate?
It does NOT mean a net 0 charge between the 2 species.
p.14
K a , pK a , K b & pK b concepts
Can you provide an example of a polyprotic acid with more than one pKa value?
Phosphate is an example of a polyprotic acid with more than one pKa value.
p.11
pH, pK, pI and K D concepts
What is pH?
pH is a measure of the acidity or basicity of a solution, representing the concentration of hydrogen ions.
p.12
Titration curve of an amino acid
Where do pKa values lie on monoprotic titration curves?
At the middle of the curves.
p.24
Bicarbonate Buffering System
What happens in the lungs in relation to the Chloride Shift?
As CO2 is reformed and leaves, chloride leaves the cell, causing RBCs to shrink.
p.6
Acid and base definitions (Arrhenius, Bronsted-Lowry, Lewis)
According to Lewis, what is the definition of an acid?
An electron-pair acceptor.
p.28
Buffering concept and systems in the body
What happens when a strong acid is added to a buffer?
The strong acid completely dissociates into its ions and the protons react with the conjugate base present to form more of the weak acid component, resulting in a slightly lower pH.
p.5
Buffering concept and systems in the body
What is an acid-base buffer?
A solution that lessens the impact of pH change from the addition of acid or base.
p.26
Bicarbonate Buffering System
What happens after absorption of available bicarbonate ions in tubular filtrate?
Remaining protons interact with HPO4^2- to form H2PO4^- which can be excreted in urine.
p.5
Buffering concept and systems in the body
What happens when 1 mL of 1 M NaOH is added to the acetate buffer?
The impact of pH change is lessened.
p.7
Strong vs Weak Acids & Bases
What are the characteristics of strong acids and bases?
They completely ionize or dissociate into their ions.
p.10
pH and pK a relationship
What does a pK a (or pK b) value closer to 0 or negative indicate?
Stronger acids (or bases).
p.25
Phosphate Buffering System
Why is the Monohydrogen phosphate considered a major species in the phosphate buffering system?
Because pKa2 is near the physiological pH of our body.
p.9
K a , pK a , K b & pK b concepts
What does K b represent in the given equation?
The base dissociation constant for the reaction MB (aq) + H2O (l) ↔ BH (aq) + MOH (aq).
p.26
Bicarbonate Buffering System
What is the function of the formed H2PO4^-?
Protons removed from extracellular fluid.
p.7
Strong vs Weak Acids & Bases
What are the characteristics of weak acids and bases?
They dissociate only to a limited extent.
p.10
pH and pK a relationship
What is the pK a (or pK b) value?
The pH value when 2 species are in equal concentration, e.g. weak acid and conjugate base.
p.9
K a , pK a , K b & pK b concepts
What does K a represent in the given equation?
<p>The acid dissociation constant for a given reaction MB (aq) + H2O (l) ↔ BH (aq) + MOH (aq). </p>
why can an amino acid acts a buffer?
<p>amine group and carboxyl group</p>
p.23
Bicarbonate Buffering System
explain the bicarbonate buffering system.
Bicarbonate Buffering System.
