Here's how they work:
* Buffers consist of a weak acid and its conjugate base (or a weak base and its conjugate acid). This means they can donate or accept protons (H+) depending on the surrounding environment.
* They resist changes in pH by absorbing excess H+ or OH- ions. When an acid is added, the buffer's conjugate base will accept the H+ ions. When a base is added, the buffer's weak acid will donate H+ ions.
Examples of important biological buffers:
* Bicarbonate buffer system: This is the most important buffer in blood, maintaining the pH around 7.4. It involves carbonic acid (H2CO3) and bicarbonate ions (HCO3-).
* Phosphate buffer system: This buffer is important in intracellular fluids and in urine. It involves dihydrogen phosphate (H2PO4-) and hydrogen phosphate (HPO42-) ions.
* Protein buffers: Proteins contain amino acids with carboxyl and amino groups that can act as buffers.
Other factors influencing pH:
* Respiration: The lungs play a role by removing carbon dioxide (CO2), which is an acidic component of the bicarbonate buffer system.
* Kidney excretion: The kidneys help regulate pH by filtering out excess acids or bases from the blood and excreting them in urine.
Disruptions to pH regulation:
* Acidosis: An excess of acid in the blood, lowering the pH.
* Alkalosis: An excess of base in the blood, raising the pH.
Understanding pH regulation is critical for:
* Maintaining cellular function: Enzymes and other biological molecules are highly sensitive to pH changes.
* Overall health: Significant deviations in pH can lead to serious medical conditions.
