Final answer:
Increasing enzyme concentration leads to an increased reaction rate and more product formation up to the point of saturation; beyond that, the reaction rate levels off due to substrate limitation.
Step-by-step explanation:
Enzymes are catalysts in biological systems that increase the rate of reactions by lowering the activation energy required for the reaction to proceed. The impact of enzyme concentration on the amount of p-nitrophenol is proportional, given that there is an excess of substrate.
When the concentration of enzyme is increased, there are more active sites available for the substrate to bind to, thus more product is formed until a point of saturation is reached.
Upon such saturation, adding more enzyme will not increase the rate of production of p-nitrophenol because the amount of substrate becomes the limiting factor. However, below this saturation point, the reaction rate will increase linearly with the increase in enzyme concentration since more enzyme molecules are available to interact with the substrate molecules, speeding up the formation of the product.