Question

Which of the following graphs depicts the effect of substrate concentration on velocity of enzyme catalysed reaction?

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is A

The question involves understanding how substrate concentration affects the velocity of an enzyme-catalyzed reaction. This relationship is typically represented by the Michaelis-Menten curve in enzyme kinetics. 

The graph that correctly depicts the effect of substrate concentration on the velocity of enzyme-catalyzed reactions is typically a hyperbolic graph. This is due to the saturation of the enzyme when the substrate concentration increases. The velocity of the reaction initially increases with an increase in substrate concentration but eventually reaches a maximum (V_max) where further increase in substrate concentration does not increase the velocity because all the active sites of the enzyme molecules are occupied.

The equation that describes this relationship is the Michaelis-Menten equation:

\(v = \frac{{V_{\max} \cdot [S]}}{{K_m + [S]}}\)

where:

• \(v\) is the reaction velocity.
• \([S]\) is the substrate concentration.
• \(V_{\max}\) is the maximum velocity.
• \(K_m\) is the Michaelis constant.

According to this model, at low substrate concentrations, the reaction velocity increases linearly with substrate concentration. As the concentration continues to rise, the increase in velocity begins to decelerate, and eventually, the reaction rate levels off when V_max is approached, leading to a plateau in the graph.

Graph 1 is a typical Michaelis-Menten plot, which is hyperbolic in shape, and correctly describes this behavior. Therefore, the correct answer is the graph shown in option represented by Graph 1.