BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Initially, an increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction. As the enzyme molecules become saturated with substrate, this increase in reaction rate levels off. The rate of an enzyme-catalyzed reaction increases with an increase in the concentration of an enzyme.

Detailed explanation-2: -As the substrate concentration increases, the enzyme reaction increases until all of the active sites are occupied by the substrate. When all active sites are occupied, the enzyme is saturated. At this saturation point, adding more substrate makes no difference to the reaction rate.

Detailed explanation-3: -Enzyme concentration: Increasing enzyme concentration will speed up the reaction, as long as there is substrate available to bind to. Once all of the substrate is bound, the reaction will no longer speed up, since there will be nothing for additional enzymes to bind to.

Detailed explanation-4: -Enzymes (and other catalysts) act by reducing the activation energy, thereby increasing the rate of reaction. The increased rate is the same in both the forward and reverse directions, since both must pass through the same transition state.

Detailed explanation-5: -The catalytic site of the enzyme is empty, waiting for substrate to bind, for much of the time, and the rate at which product can be formed is limited by the concentration of substrate which is available. (B) As the concentration of substrate increases, the enzyme becomes saturated with substrate.