Why in biochemistry experiments is a buffer of pH 7.0 often used?

Answer 1

A buffer of pH 7.0 keeps the concentration of hydronium ions in the solution at about neutral conditions. Solutions of pH >7 are basic and <7 are acidic. The amount of H+ (an abbreviation for hydronium) will change how enzymes and other molecules we investigate in biochemistry react. For instance, in acidic solution, hemoglobin has a lower binding affinity for oxygen. Also, when a protein is out of its normal pH range, it can denature (lose its normal structure). In some experiments, a buffer of a different pH is used, but 7.0 is common because the pH in a lot of living things is very close to 7.

Probably the most common buffer used for this kind of thing is phosphate-buffered saline. Depending on the experiment, I might adjust the pH to 7.5 maybe. Tris-buffered saline is another common buffer, this one is more basic (higher pH) than PBS.

Remember also to consider the salt concentration of the solution; after the acidity this is another important factor.