The pH Scale
2. From Acidic to Alkaline
Lets quickly revisit the pH scale. Remember those science class experiments with litmus paper turning red or blue? That was all about detecting pH! Acids, like vinegar, have a pH less than 7. They donate hydrogen ions (H+) to a solution. Bases, like bleach, have a pH greater than 7 and accept hydrogen ions. Pure water is considered neutral, with a pH of 7.
The pH scale is logarithmic, meaning that each whole number change represents a tenfold change in acidity or alkalinity. So, a solution with a pH of 6 is ten times more acidic than a solution with a pH of 7, and a hundred times more acidic than a solution with a pH of 8! This logarithmic scale highlights how even small changes in pH can have big effects on enzymes.
Our bodies are masters of maintaining a stable pH. Blood, for example, needs to stay within a very narrow range (around 7.4) to function properly. Buffers in our blood help to resist changes in pH when we eat acidic foods or produce metabolic waste. This tight regulation is essential for enzyme activity and, ultimately, for our survival. Without it, our internal chemistry would be a chaotic mess!.
Different parts of the body have different pH levels designed to support the enzymes working there. The stomach, for instance, has a highly acidic environment (pH 1.5-3.5) to activate pepsin, an enzyme that breaks down proteins. In contrast, the small intestine is more alkaline (pH 7-9) to accommodate enzymes from the pancreas that digest fats and carbohydrates. Nature is pretty clever when it comes to optimizing conditions for enzymes!
