Final answer:
A buffer is a substance produced by living cells to absorb excess hydrogen and hydroxide ions, preventing sudden changes in pH. The bicarbonate system in the human body is one example of a natural buffer. Buffers maintain the pH balance in blood and other bodily fluids essential for proper physiological functions.
Step-by-step explanation:
The substance produced by living cells to prevent sudden changes in pH is known as a buffer. Buffers work by absorbing excess hydrogen (H+) and hydroxide (OH−) ions. One example of a buffer system in the human body is the bicarbonate system, which involves bicarbonate ions (HCO3−) and carbonic acid (H2CO3/CO2(aq)). This system helps to maintain the pH of blood around 7.4, which is essential for proper physiological functioning.
A buffer consists of a weak acid and its conjugate base and can neutralize small amounts of added acids or bases in body fluids. For instance, when a slight acidification occurs, the buffer can bind excess H+ ions, whereas, in the case of alkalization, it can release H+ to maintain pH balance. The balance between the concentrations of acids and bases in the blood is critical, and the body employs various buffering systems, including those based on phosphate ions, to maintain this balance.