Question

Explain the following terms:
(a) Essential amino acids:
(b) Peptide bond:
(c) Denaturation:

Hint:

Essential amino acids must be obtained from food. Peptide bonds link amino acids to form proteins, and denaturation disrupts protein structure and function.

Answer 1

(a) Essential amino acids:
Essential amino acids are amino acids that cannot be synthesized by the body. As a result, they must be obtained from the diet. Examples of essential amino acids include leucine, lysine, and tryptophan. These amino acids are crucial for protein synthesis and other metabolic functions but must be consumed in the diet because the body lacks the necessary enzymes to synthesize them.
(b) Peptide bond:
A peptide bond is a covalent bond formed between two amino acids. It occurs when the carboxyl group (-COOH) of one amino acid reacts with the amino group (-NH$_2$) of another amino acid, releasing a molecule of water (dehydration synthesis). This results in the formation of a dipeptide and a peptide bond between the two amino acids. Peptide bonds are the linkages that hold amino acids together in proteins.
(c) Denaturation:
Denaturation refers to the process by which a protein loses its native, functional conformation due to external factors such as heat, pH changes, or chemical agents. Denaturation disrupts the secondary and tertiary structures of the protein, causing it to lose its biological activity. For example, when an egg is boiled, the proteins in the egg white denature and solidify, which changes the texture and properties of the egg.