Question

Increasing the substrate concentration beyond a certain point does not increase the rate of reaction. Why?

• A. Substrate and enzyme lose their affinity for each other with increasing substrate concentration
• B. With increasing substrate concentration there is no free space available for the reaction to occur
• C. With increasing substrate concentration, pH of the reaction medium changes
• D. There are no free enzymes available to react with the increased number of substrates

Answer 1

The correct option is D There are no free enzymes available to react with the increased number of substrates

Substrate and enzyme lose their affinity for each other with increasing substrate concentration
With increasing substrate concentration there is no free space available for the reaction to occur
With increasing substrate concentration, pH of the reaction medium changes
There are no free enzymes available to react with the increased number of substrates
With the increase in concentration of the substrate, the rate of enzyme activity increases, but to a certain limit. The graph is not a linear one. The limit is till when all the active sites of all the enzymes available are occupied by the substrate molecules. Increasing substrate concentration beyond this point has no additional effect as there are no free enzyme molecules available to carry out the reaction.
Increase in the substrate concentration has no effect on its affinity towards the enzyme, or the pH of the reaction medium.