Which of the following graphs correctly indicates the reaction in presence (indicated +) and absence (indicated as -) of an enzyme ?

Options

A.
B.
C.
D.

Answer

D

Explanation

Enzymes are biocatalysts that greatly increase the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and `pH`, which must lie within certain range. Increase in substrate concentration increase the rate of reaction. The enhanced rate is due to two factors: (a) occupation of more and more active sites by the substrate molecules, (b) higher number of collsions between substrate molecules. The rise in velocity is quite high in the beginning but it decreases progressively with the substrate concentration. A stage is reached where velocity is maximum. It does not increase further by increasing the substrate concentration. At this stage the enzyme molecules become fully saturated and no active site is left to bind additional substrate molecules. This saturation effect is shown by all enzymes.