What is the primary function of buffers in relation to pH levels?

Buffers play a critical role in maintaining homeostasis within biological systems, particularly by stabilizing pH levels. Their primary function is to resist drastic changes in pH by either donating or accepting hydrogen ions (H⁺). This process allows buffers to keep the pH of solutions, such as blood and intracellular fluid, relatively constant despite the addition of acids or bases or metabolic processes that could otherwise alter pH.

For example, in human physiology, bicarbonate serves as a crucial buffer in blood, helping to maintain a pH around 7.4. When excess H⁺ ions are added (which would lower pH), the bicarbonate can absorb those ions, thereby minimizing the pH change. Conversely, if there is a loss of H⁺ ions (which would raise pH), the bicarbonate can release H⁺ ions to help stabilize the pH.

This buffering capacity is essential for proper cellular function, as many biological processes are pH-sensitive. Therefore, the main purpose of buffers is to maintain a relatively constant pH, which is vital for the health and function of living organisms.