The effect of increased substrate concentration on the rate of enzymatic reaction can be understood through the Michaelis-Menten kinetics model. As the substrate concentration increases, the rate of the enzymatic reaction also increases, but up to a certain point. This is because enzymes have a limited number of active sites where the substrate can bind and form enzyme-substrate complexes. Initially, when the substrate concentration is low, there are many free enzyme molecules available, and the reaction rate increases linearly with the increase in substrate concentration. However, as the substrate concentration continues to increase, the enzyme active sites become saturated, meaning that most of the enzyme molecules are bound to substrate molecules. At this point, the reaction rate reaches its maximum velocity Vmax , and further increases in substrate concentration do not significantly affect the reaction rate.Competitive inhibition affects this relationship by introducing a molecule that competes with the substrate for the enzyme's active site. The competitive inhibitor has a similar structure to the substrate and can bind to the enzyme's active site, preventing the substrate from binding and forming the enzyme-substrate complex. This results in a decrease in the reaction rate.In the presence of a competitive inhibitor, the effect of increased substrate concentration on the rate of enzymatic reaction changes. The reaction rate still increases with increasing substrate concentration, but it requires a higher substrate concentration to reach the same reaction rate as in the absence of the inhibitor. This is because the substrate has to compete with the inhibitor for the enzyme's active sites. The maximum velocity Vmax of the reaction remains the same, but the apparent affinity of the enzyme for the substrate represented by the Michaelis constant, Km decreases, meaning that a higher substrate concentration is needed to achieve half of the maximum reaction rate.In summary, increased substrate concentration generally increases the rate of enzymatic reactions until saturation is reached. Competitive inhibition affects this relationship by decreasing the apparent affinity of the enzyme for the substrate, requiring higher substrate concentrations to achieve the same reaction rate.