Peptide bond is formed when the

Carboxyl group of one amino acid reacts with amino group of the next amino acid.

The correct answer is Option (3) -Carboxyl group of one amino acid reacts with amino group of the next amino acid.

Proteins are polypeptides. They are linear chains of amino acids linked by peptide bonds. Each protein is a polymer of amino acids.

As there are 20 types of amino acids (e.g., alanine, cysteine, proline, tryptophan, lysine, etc.), a protein is a heteropolymer and not a homopolymer .

In a polypeptide or a protein, amino acids are linked by a peptide bond which is formed when the carboxyl (-COOH) group of one amino acid reacts with the amino (-NH2 ) group of the next amino acid with the elimination of a water moiety (the process is called dehydration).

In a polysaccharide the individual monosaccharides are linked by a glycosidic bond. This bond is also formed by dehydration. This bond is formed between two carbon atoms of two adjacent monosaccharides