Chapter 23, Problem 45A

Interpretation Introduction

Interpretation:

The method or cause by which enzymes lower the activation energy for a reaction should be determined.

Concept introduction:

Proteins are polymeric biomolecules which are formed by the polymerisation of amino acids. Amino acids are the organic molecules with $–{\text{NH}}_{\text{2}}$ and −COOH functional groups bonded on same carbon atom of the molecule.

They polymerise by peptide linkage to form dipeptide, oligopeptide and polypeptide molecules. Each peptide bond formation is a condensation reaction that occurs with the elimination of water molecule.

Explanation of Solution

The biological molecules which speed up the rate of a chemical reactions takes place in cells are known as enzymes. The enzyme region where molecules of the substrate binds and perform a chemical reaction is known as an active site. The active site of an enzyme composed of residues of amino acids which form temporary bonds with the binding site that is substrate and the shape of substrate changes by forming enzyme-substrate complex. Due to large size of enzymes, they can able to form multiple bonds with binding site (substrate). The forces formed between enzyme (amino acid chains) and substrate lower the activation energy. In this way, the activation energy of chemical reaction get lowers by enzyme results in the increase in speed of reaction. This also results in the decrease in substrate molecules as it is directly proportional to energy.