Presentation on theme: "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."— Presentation transcript:
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). ALL LIFE PROCESSES DEPEND ON THIS TINY IONIZATION PROCESS… 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.
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 (0.0000001 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.
acid A proton donor is known as an acid. Acids base 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.
1 X 10 -1 [H+] = pH 1 HCl or stomach acid 1 X 10 -13 [OH--] = pH 1 HCl or stomach acid
[H+] pH 1 pH 7pH 14 [OH—] What happens to the pH of the solution if the level of [H+] increases? What happens to the pH of the solution if the level of [OH–] increases?
CO 2 What does exhaling into the water add to the water? H2OH2O Bromothymol Blue added
CO 2 How does this ‘change’ the water? Why? CO 2 + H 2 O H 2 CO 3 Carbonic Acid H2OH2OCO 2
Buffer Systems —a buffer is a molecule that tends to either bind or release hydrogen ions in order to maintain a particular pH What happens when the reactions go to the right? What happens if the reactions go to the left? Carbonic acid Bicarbonate Ion Carbonate Ion
H 2 CO 3 HCO 3 -- = carbonic acid (H+ donor) responds to a rise in pH = bicarbonate (H+ acceptor) responds to a drop in pH [H+] pH 1 pH 7pH 14
Carbonic acid Bicarbonate Ion A diabetic’s blood pH dropped to 7.23. 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 Maintaining blood pH—why? Acidosis or Alkalosis = death
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
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… pH in the Digestive System, producing HCl
Lumen of the Stomach Esophagus “peristalsis” Small Intestine
H 2 CO 3 HCO 3 = carbonic acid (H+ donor) responds to a rise in pH = bicarbonate (H+ acceptor) responds to a drop in pH [H+] pH 1 pH 7pH 14
The Stomach—secretion of HCl Movement of molecules by active transport or facilitated diffusion Cl- HCO 3 - Cl- H+ HCl CO 2 + H2OH2O H 2 CO 3 H+HCO 3 - Capillary Blood vessel Parietal cell Lumen of stomach Cl- + Bicarbonate ion Carbonic Acid
H 2 CO 3 HCO 3 - H+ + Buffer system in place to regulate pH Carbonic AcidBicarbonate Hydrogen ion