Bicarbonate Essay, Research Paper
Bicarbonate: A good buffer for blood Most carbon dioxide generated
during metabolism is transported in the form of bicarbonate ions,
which result from the dissociation of carbonic acid formed in the red
blood cells from the chemical union of carbon dioxide and water.
Hydrogen ions from the dissociation are bound to hemoglobin and
other proteins, serving to buffer the blood. The entire process is
reversed when blood enters the lungs, allowing free carbon dioxide to
diffuse into the environment. One of the most important cases of
chemical balance in the blood is the exchange of the gases oxygen
and carbon dioxide. The hemoglobin also helps the blood transport
carbon dioxide and assists in buffering the blood. Carbon dioxide
diffuses into the blood plasma and then into the red blood cells,
where the CO2 is converted to bicarbonate. Carbon dioxide first
reacts with water to form carbonic acid, which then dissociates into a
hydrogen ion and a bicarbonate ion. As blood flows through the
lungs, the process is reversed. Diffusion of CO2 out of the blood
shifts the chemical equilibrium within red cells in favor of the
conversion of bicarbonate to CO2. Carbonic acid dissociates into a
bicarbonate ion and a hydrogen ion. Hemoglobin binds most of the
H+ ions from carbonic acid, preventing them from acidifying the
blood. The reversibility of the carbonic acid-bicarbonate conversion
also helps buffer the blood, releasing or removing H+. Overall,
Bicarbonate is a good buffer for blood because of its remarkable
ability to resist changes in pH at given regions indicated by the
minimum slope on its titration curves. These curves are when both
the concentrations of the weak acid and its conjugate base are equal.
If the pH of the blood falls, the concentration of H2CO3 increases to
eat up the H+. In addition H2CO3 dissociates to form CO2 and H20.
If the pH of the blood increases, the concentration of HCO3-
increases to release H+. In this case CO2 and H2O react to form
H2CO3 to replenish the supply of H+.