Question

an enzyme used for a reaction is most effective at the optimal ph. the graph shows the effect of ph on the rate of the reaction.
which statement best explains the activity of the enzyme between ph 8 and 11?
the wrong substrate blocks the active site of the enzyme.
the enzyme is used up at lower ph values, and none is available.
the ability of the enzyme to bind with a substrate is reduced.
the enzyme functions at a faster rate, increasing the production of product.

Explanation:

Enzyme activity is affected by pH. The graph shows the rate of reaction (enzyme activity) vs pH. At optimal pH, the enzyme's active site has the correct conformation for substrate binding. Between pH 8 and 11 (moving away from optimal pH, likely above optimal here as optimal is around 8 - 9 from the graph), the enzyme's structure (including active site) is altered due to pH changes, reducing its ability to bind substrate. The first option is incorrect as there's no mention of wrong substrate blocking. The second is wrong as enzymes aren't used up. The fourth is incorrect as the rate would decrease or be sub - optimal here, not increase.

Answer:

The ability of the enzyme to bind with a substrate is reduced.