Question

If the experiment is repeated at pH 11, the observed activity level of the enzyme will most likely be?

1) Higher than at pH 7
2) Lower than at pH 7
3) The same as at pH 7
4) Cannot be determined

Answer 1

At pH 11, which is significantly more alkaline than the enzyme's optimal pH of 7.2, the activity level of the enzyme will most likely be lower than at pH 7.

Step-by-step explanation:

The activity level of an enzyme is highly dependent on the pH level of its environment. Given that the optimum pH for the enzyme is 7.2, an increase to pH 11 would likely cause a decrease in enzyme activity. Enzymes are sensitive to pH changes because the ionization of amino acid side chains in the active site can alter the enzyme's structure and its ability to bind to the substrate. Typically, moving away from an enzyme's optimum pH results in a reduced rate of catalysis due to denaturation or changes in the charge state of the active site that are critical for substrate binding and catalytic activity.

When the pH increases beyond the optimum, it typically becomes more alkaline, negatively affecting enzymes that are not adapted for such conditions. Since the given enzyme has an optimum pH of 7.2, we can infer that it functions best in a nearly neutral environment. Thus, at pH 11, which is considerably more alkaline than the enzyme's optimum pH, it is very likely that the enzyme's activity will be lower compared to its activity at pH 7.