Final answer:
On a Lineweaver-Burk graph, the addition of a competitive inhibitor increases the slope of the line as the apparent Km increases, but the y-axis intercept (1/Vmax) remains unchanged, showing that Vmax is not affected by competitive inhibitors.
Step-by-step explanation:
The student asked what effect is seen on a Lineweaver-Burk graph when a competitive inhibitor is added. The Lineweaver-Burk plot is a double reciprocal graph used in enzyme kinetics that transforms the hyperbolic curvature of Michaelis-Menten kinetics into a linear plot. In the absence of an inhibitor, this plot results in a straight line.
When a competitive inhibitor is present, the line on the Lineweaver-Burk plot shifts in a specific manner due to changes in the kinetic parameters of the enzyme. Competitive inhibition increases the apparent Michaelis constant (Km) without affecting the maximal velocity (Vmax) of the enzyme. This results in an increase in the slope of the line in the Lineweaver-Burk plot, as Km becomes larger when plotted as 1/Km. However, since Vmax remains unchanged, the vertical intercept (1/Vmax) does not change. Thus, lines with and without competitive inhibitor intersect at the same point on the y-axis, which represents 1/Vmax, indicating that competitive inhibitors do not impact the maximal rate of the reaction.