Question

Microorganisms and enzymes are used as catalysts to alter the rate of biochemical reactions. Explain with evidence and facts that how catalysts alter the rate of biochemical reactions.

Answer 1

Catalysts alter the rate of biochemical reactions by following ways:

The reactants have a wide range of kinetic energies, and only a small fraction of them will have enough energy and the correct orientation to actually break bonds, so that a chemical reaction can take place. The minimum energy that is needed for a reaction to take place is called the activation energy.

The catalyst act by lowering the activation energy so that a greater proportion of the particles have enough energy to react. A catalyst lower the activation energy for a reaction by:

• reacting with the reactants to form an intermediate that requires lower energy to form the product
• or by changing the orientation of the reacting particles in such a way that successful collisions are more likely to happen.

The catalyst is then released at the end of the reaction, completely unchanged.

-Enzymes and chemical catalysts increase the rate of a chemical reaction in both directions, forward and reverse. This principle of catalysis follows from the fact that catalysts can't change the equilibrium of a reaction.

Enzyme catalysis can be divided into 6 with examples :

1)Oxidation and reduction- Enzymes that carry out these reactions are called oxidoreductases.

example, alcohol dehydrogenase converts primary alcohols to aldehyde.

2)Hydrolysis- These enzymes, termed as hydrolases, break single bonds by adding the elements of water.

example, phosphatases break the oxygen‐phosphorus bond of phosphate esters.

3)Transferases- They move functional groups from one molecule to another.

example, alanine aminotransferase shuffles the alpha‐amino group between alanine and aspartate.

4)Formation or removal of a double bond with group transfer- The functional groups transferred include amino groups, water, and ammonia.

example, decarboxylases remove CO 2 from alpha‐ or beta‐keto acids. Dehydratases remove water, as in fumarase.

5) Ligase- Single bond formation by eliminating the elements of water.  

6) Isomerase- Isomerization of functional groups. The position of a functional group is changed within a molecule, but the molecule contains the same number and kind of atoms like beginning. So,the substrate and product of the reaction are isomers. example, triose phosphate isomerase.