Michaelis-Menten kinetics describes what?

Michaelis-Menten kinetics describes what?

• A. A model for gas-phase reactions
• B. A model describing enzyme kinetics with v = Vmax[S]/(Km + [S])
• C. A model for linear diffusion
• D. A law relating pressure, volume, and temperature

Answer: (C)

Michaelis-Menten kinetics describes how the rate of an enzyme-catalyzed reaction depends on substrate concentration, captured by the rate expression v = Vmax[S]/(Km + [S]). This model comes from the idea that the substrate binds to the enzyme to form an enzyme–substrate complex, which then converts to product. The steady-state assumption keeps the complex concentration roughly constant, leading to the hyperbolic relationship between v and [S]. Key features: at low [S], the rate rises approximately linearly with substrate, showing first-order behavior with respect to [S]. At high [S], the rate levels off toward a maximum, Vmax, because the enzyme becomes saturated with substrate and cannot process faster. Km, the Michaelis constant, is the substrate concentration at which the rate is half of Vmax. It provides a sense of the enzyme’s affinity for the substrate: a smaller Km means tighter binding and faster turnover at lower concentrations. This framework is specific to enzyme kinetics and does not describe gas-phase reactions, diffusion processes, or general gas-law relationships like PV = nRT.

Michaelis-Menten kinetics describes how the rate of an enzyme-catalyzed reaction depends on substrate concentration, captured by the rate expression v = Vmax[S]/(Km + [S]). This model comes from the idea that the substrate binds to the enzyme to form an enzyme–substrate complex, which then converts to product. The steady-state assumption keeps the complex concentration roughly constant, leading to the hyperbolic relationship between v and [S].

Key features: at low [S], the rate rises approximately linearly with substrate, showing first-order behavior with respect to [S]. At high [S], the rate levels off toward a maximum, Vmax, because the enzyme becomes saturated with substrate and cannot process faster. Km, the Michaelis constant, is the substrate concentration at which the rate is half of Vmax. It provides a sense of the enzyme’s affinity for the substrate: a smaller Km means tighter binding and faster turnover at lower concentrations.

This framework is specific to enzyme kinetics and does not describe gas-phase reactions, diffusion processes, or general gas-law relationships like PV = nRT.