1. Buffers
Post Lab Analysis

2. ALL LIFE PROCESSES DEPEND ON THIS TINY IONIZATION PROCESS…
Water = nonionic compound. It is converted to ions in a process called ionization.
Water separates when one of the OH bonds breaks.
This results in a positively charged H+ (hydrogen ion)
and a negatively charged OH— (hydroxide ion).
Imagine a water molecule that picks up a positively charged hydrogen proton.
When this happens, this water molecule
becomes positively charged. 
The water molecule that gave up the hydrogen proton becomes negatively charged
because one 1 electron remained behind. 

3. The level of H+ and OH— ions in solution is known as the pH scale
The proton exchange results in 2 water molecules
out of every 1 billion splitting into a
positively charged H3O+ (called hydronium) ion
and a negatively charge OH- (called hydroxide) ion. 
Pure water, contains hydronium ions equal to 1 x 10-7 moles per liter ( moles per liter).  In other words, the number of hydronium ions
Is equal to number of hydroxide ions. Therefore, the hydroxide ions are equal to
1 x 10-7 moles per liter.
This equilibrium between hydronium and hydroxide ions is affected by the addition of substances
to water.
The level of H+ and OH— ions in solution
is known as the pH scale

4. A proton donor is known as an acid.
Acids increase the [H+] ions in solution.  A base functions as a proton acceptor,
it reduces the concentration of [H+] in solution
and increases the concentration of [OH--] ions.

5. 1  X 10-1 [H+] = pH 1 HCl or stomach acid
1  X [OH--] = pH HCl or stomach acid

6. [H+] [OH—] pH 1 pH 7 pH 14 What happens to the pH of the solution
if the level of [H+] increases?
if the level of [OH–] increases?

7. CO2 What does exhaling into the water add to the water? H2O
Bromothymol Blue added

8. CO2 CO2 + H2O How does this ‘change’ the water? Why? H2CO3 CO2 H2O
Carbonic Acid

9. Buffer Systems—a buffer is a molecule
that tends to either bind or release hydrogen ions
in order to maintain a particular pH
Bicarbonate
Ion
Carbonate
Ion
Carbonic
acid
What happens when the reactions go to the right?
What happens if the reactions go to the left?

10. H2CO3 HCO3 -- = carbonic acid (H+ donor) responds to a rise in pH [H+]
= bicarbonate (H+ acceptor) responds to a drop in pH

11. A diabetic’s blood pH dropped to 7.23. Why?
Bicarbonate
Ion
Carbonic
acid
Maintaining blood pH—why?
Acidosis or Alkalosis = death
A diabetic’s blood pH dropped to Why?
The body enters a starving state due to no insulin output; body burns
stored fat for energy and ketones are released into the bloodstream
as a by-product/or waste product of fat metabolism. Ketones are acidic!
What happens during HYPERventilation?
Levels of Carbon dioxide decrease; less H+ ions will accumulate
causing the pH of blood to increase = alkalosis
What happens during HYPOventilation?
Carbon dioxide in blood increases; more H+ ions will accumulate
causing the pH of blood to decrease

12. What do the lungs do? In general, acids (H+ ions) are stimulating to neurons.
As the carbon dioxide level in the blood increases,
it also increases in the cerebrospinal fluid (CSF).
This causes the pH to drop; especially in the brain
because there is less buffering ability in CSF than in blood.
The low pH (excess H+ ions) stimulates neurons in the
medullary respiratory centers to fire more impulses to the
diaphragm to increase the rate and depth of breathing.
What do the kidneys do?
Regulates HCO3- ions in blood
loss of HCO3- ions in blood = decrease blood pH = metabolic acidosis
gain of HCO3- ions in blood = increase blood pH = metabolic alkalosis

13. pH in the Digestive System, producing HCl
Parietal Cells of the stomach
secrete HCl into the stomach
to disrupt the extracellular matrix
and kills most bacteria that
are swallowed up with food…
HCl converts inactive pepsinogen (which
is secreted by chief cells of the stomach)
into active pepsin
Pepsin begins the chemical digestion
of proteins by splitting the polypeptides
into smaller polypeptides…

14. Esophagus
“peristalsis”
Lumen of the Stomach
Small Intestine

15. H2CO3 HCO3 = carbonic acid (H+ donor) responds to a rise in pH [H+]
= bicarbonate (H+ acceptor) responds to a drop in pH

16. The Stomach—secretion of HCl
Movement of molecules by active transport or facilitated diffusion
Parietal cell
Lumen of stomach
Cl-
Cl-
Cl- +
CO2
H2O
HCl
Capillary
Blood
vessel
Carbonic Acid
H2CO3 H+
HCO3- + H+
HCO3-
Bicarbonate ion

17. H2CO3 H+ HCO3- + Buffer system in place to regulate pH Carbonic Acid
Bicarbonate
Hydrogen ion
H2CO3 H+
HCO3- +
Buffer system in place to regulate pH