Here's a breakdown:
* Proteins: Many proteins have amino acid side chains with functional groups that can act as weak acids or bases. This allows them to absorb excess hydrogen ions (H+) or hydroxide ions (OH-) to maintain a stable pH. For example, hemoglobin in red blood cells is a major protein buffer.
* Bicarbonate ions (HCO3-): This system is the most important buffer in the blood. Carbon dioxide (CO2) dissolves in blood and reacts with water to form carbonic acid (H2CO3), which dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). This system is tightly regulated by the lungs and kidneys to maintain blood pH within a narrow range.
Other important buffers include:
* Phosphate ions (HPO42- and H2PO4-): Found in both intracellular and extracellular fluids, phosphates help buffer pH by accepting or donating protons.
* Ammonia (NH3): Produced as a byproduct of protein metabolism, ammonia can buffer excess H+ in the body.
These buffers are essential for maintaining the delicate pH balance in the human body, which is vital for optimal functioning of various organs and cellular processes.
