Final Answer:
The units for Km (Michaelis-Menten constant) in a Lineweaver-Burk plot should be Molarity (M) (Option A).
Step-by-step explanation:
In the Lineweaver-Burk plot, the Michaelis-Menten constant (Km) is determined from the x-intercept. The Lineweaver-Burk plot represents the reciprocal of the reaction rate (1/V) against the reciprocal of the substrate concentration (1/[S]). The slope of the plot is Km/Vmax, where Vmax is the maximum reaction rate. Since Km is derived from the x-intercept, which is expressed as 1/[S], the units for Km are reciprocal to the units of substrate concentration, making it Molarity (M).
The Lineweaver-Burk plot is a graphical representation used in enzyme kinetics to determine kinetic parameters such as Km and Vmax. It provides a linear relationship that simplifies the determination of these parameters. By analyzing the x-intercept of the Lineweaver-Burk plot, Km can be calculated, and the units for Km are consistent with the reciprocal of substrate concentration, i.e., Molarity (M).
In conclusion, the correct units for Km in a Lineweaver-Burk plot are Molarity (M). This choice aligns with the reciprocal of substrate concentration, providing a practical and widely accepted representation in the field of enzyme kinetics (Option A).