Question

Of the following statements about enzymes, which ones are true?
(i) enzymes lack in nucleophilic group
(ii) enzymes are highly specific both in the binding chiral substrate and in catalyzing their reaction
(iii) enzyme catalyzes the chemical reaction by lowering the activation energy
(iv) pepsin in proteolytic enzyme
a. (i)
b. (i) and (iv)
c. (i) and (iii)
d. (ii), (iii) and (iv)

Answer 1

Hint: Enzymes are the biocatalysts which catalyze the reaction in a cell. They are the macromolecules with a higher molecular weight. They can break down a bigger molecule into smaller ones or can bind smaller molecules to make a bigger one. Enzymes only catalyze the reaction and do not get involved directly in the reaction.
Step by step solution:

• • Enzymes enhance the rate of reaction. Enzymes have a substrate binding site on which the substrate binds and forms an enzyme-substrate complex.

• Enzymes work by lowering the activation energy so that the reaction can take place efficiently.

• They do not involve themselves in the reaction directly but only speed up the reaction and do not change the direction of the reaction.

• Proteolytic enzymes are the enzymes which catalyze the breakdown of proteins into smaller peptides or amino acids. Pepsin is a proteolytic enzyme.

So, option is D correct.

Note: Enzymes are very specific in action. They follow a key lock mechanism. There is a specific enzyme for a specific substrate and reaction. Enzymes bind with substrate on the substrate binding site present on the enzyme. Enzymes gets deactivated or denatured at very high temperature and show maximum activity at optimum temperature.