Question

Enzymes are basically
a. Sugars
b. Proteins
c. Fats
d. Vitamins

Answer 1

Hint: To function as enzymes a molecule must have the ability to change its shape and have certain crevices or pockets where a molecule can bind to and get transformed.

Complete step-by-step solution:
Enzymes are mainly proteins with the exception of some catalytic RNA, which acts as catalysts in some chemical reactions. They function through a variety of mechanisms but all of them increase the rate of reaction by lowering the activation energy required by the reaction.

Some of the main characteristics of enzymes are as follows:
1. Enzymes are highly specific for a particular substrate. They have an active site that has a strong affinity for a specific substrate. It slightly changes its conformation, known as an “induced fit” to accommodate the target substrate and bring the necessary changes for product formation.
2. Enzymes do not undergo any change during the reaction. Enzyme’s amino acid residues may break or form covalent bonds with the substrate but it will typically reform those bonds thus enabling the enzyme to be available for other substrates.
3. Enzymes are very efficient, they catalyze about 1-10,000 molecules of substrate per second.
4. There is no effect of the enzyme on its equilibrium constant or Keq.
5. Enzymes have sites other than active sites called allosteric sites. They can be controlled allosterically by a variety of means.

So, the correct answer is ‘Proteins’.

Note:
1. According to the International Union of Biochemists (IUB), the enzymes are divided into 6 functional classes based on the nature of the reaction they catalyze. The six types of enzymes are - oxidoreductases, hydrolases, transferases, lyases, isomerases, and ligases.
2. There are enzymes that do not need any additional components to show their full activity. While others require non-protein molecules called cofactors for their activity. Cofactors can be either inorganic like- metal ions and iron-sulfur clusters or organic compounds like flavin and heme.