Question

What is the chemical nature of enzymes?
A. Protein
B. Nucleic acid
C. Carbohydrate
D. Lipid
E. Steroid

Answer 1

Enzyme is a substance that acts as a catalyst in living organisms. It regulates the rate at which chemical reactions proceed without itself being altered in the process.

Complete Answer:
- Most of the biological processes that occur within living organisms are regulated by enzymes. Enzymes catalyze all aspects of cell metabolism. This includes the digestion of food, in which large nutrient molecules (such as proteins, carbohydrates, and fats) are broken down into smaller molecules, the conservation and transformation of chemical energy, and the construction of cellular macromolecules from smaller precursors. Many inherited human diseases, such as albinism and phenylketonuria, result from a deficiency of a particular enzyme.

- Like all catalysts, enzymes increase the reaction rate by lowering its activation energy. Some enzymes can make the conversion process of a substrate to product occur many times faster. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific.

- Enzyme activities are affected by inhibitors, molecules that decrease enzyme activity; activators, molecules that increase activity; many therapeutic drugs and poisons are enzyme inhibitors. An enzyme’s activity decreases outside its optimal temperature and pH. Many enzymes are permanently denatured when exposed to excessive heat, losing their structure, and catalytic properties.

- A large protein enzyme molecule consists of one or more amino acid chains known as the polypeptide chains. The amino acid sequence determines the characteristic folding patterns of the protein’s structure, which is essential to enzyme specificity.

Hence, the correct option is A, ‘protein’.

Note: Cofactor is an additional component, bound to some enzymes, which is a participant in the catalytic event and hence is required for the enzymatic activity.