Final answer:
Living things require a stable pH balance because enzymes, which are crucial for biochemical reactions, operate within specific pH ranges. Buffering systems in the body help maintain this balance by moderating the pH and preventing enzyme denaturation.
Step-by-step explanation:
Living things must maintain a fairly constant pH balance because the pH level determines the proper functioning of enzymes, which are essential for biochemical reactions. The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 are acidic, and above 7 are basic. Most enzymes operate within a specific pH range, and the body uses buffering systems to maintain the pH balance within this range. These buffers can absorb excess hydrogen ions (in the case of increased acidity) or hydroxide ions (in the case of increased alkalinity), preventing radical changes in the pH which could denature enzymes and impair biological functions. The acid-base balance is critical, as extreme pH levels can disrupt molecular stability and interactions, leading to detriments in life-sustaining processes.