Figure 6.2 Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme held constant.
-For the enzyme-catalyzed reaction shown in Figure 6.2, which of these treatments will cause the greatest increase in the rate of the reaction if the initial reactant concentration is 1.0 micromolar?
A) doubling the activation energy needed
B) cooling the reaction by 10°C
C) doubling the concentration of the reactants to 2.0 micromolar
D) doubling the enzyme concentration
E) increasing the concentration of reactants to 10.0 micromolar, while reducing the concentration of enzyme by half

Question

Figure 6.2 Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme held constant.
-For the enzyme-catalyzed reaction shown in Figure 6.2, which of these treatments will cause the greatest increase in the rate of the reaction if the initial reactant concentration is 1.0 micromolar?
A) doubling the activation energy needed 
B) cooling the reaction by 10°C 
C) doubling the concentration of the reactants to 2.0 micromolar 
D) doubling the enzyme concentration 
E) increasing the concentration of reactants to 10.0 micromolar, while reducing the concentration of enzyme by half

Quizplus · Accepted Answer

The greatest increase in the rate of the reaction will occur by doubling the enzyme concentration (choice D), as this will increase the number of enzyme-substrate interactions and thus increase the rate of reaction. Increasing the concentration of reactants (choice C) will also increase the rate to some extent, but doubling the enzyme concentration will have a greater effect. Doubling the activation energy needed (choice A) or cooling the reaction by 10°C (choice B) will decrease the reaction rate. Increasing the concentration of reactants to 10.0 micromolar while reducing the concentration of enzyme by half (choice E) may have a similar effect on the rate as doubling the reactant concentration to 2.0 micromolar, but it will also reduce the number of enzyme-substrate interactions, resulting in a smaller overall increase in the rate.

Figure 62 Rate of an Enzyme-Catalyzed Reaction as a Function of of Varying