Biomolecules MCQs for NEET — Chemistry Questions with Answers

As per the NCERT text, 'The reaction between two molecules of similar or different amino acids, proceeds through the combination of the amino group of one molecule with the carboxyl group of the other. This results in the elimination of a water molecule and formation of a peptide bond –CO–NH–.' (Biomolecules_chemistry, page 292).

The NCERT states, 'When the number of such amino acids is more than ten, then the products are called polypeptides.' (Biomolecules_chemistry, page 293).

The NCERT text specifies, 'For example, when carboxyl group of glycine combines with the amino group of alanine we get a dipeptide, glycylalanine.' (Biomolecules_chemistry, page 292).

The NCERT text mentions, 'A tripeptide contains three amino acids linked by two peptide linkages.' (Biomolecules_chemistry, page 292).

The NCERT text defines it as, 'A polypeptide with more than hundred amino acid residues, having molecular mass higher than 10,000u is called a protein.' (Biomolecules_chemistry, page 293).

The NCERT text states, 'Polypeptides with fewer amino acids are likely to be called proteins if they ordinarily have a well defined conformation of a protein such as insulin which contains 51 amino acids.' (Biomolecules_chemistry, page 293).

The NCERT Biology text explains, 'The left end represented by the first amino acid and the right end represented by the last amino acid. The first amino acid is also called as N-terminal amino acid.' (BIOMOLECULES_biology, page 112).

The NCERT text clearly states, 'Chemically, peptide linkage is an amide formed between –COOH group and –NH2 group.' (Biomolecules_chemistry, page 292).

The NCERT text explains, 'Any change in this primary structure i.e., the sequence of amino acids creates a different protein.' (Biomolecules_chemistry, page 293).

The primary structure is defined by the sequence of amino acids linked by peptide (amide) bonds, which are covalent. Ester bonds are not involved in linking amino acids in the primary structure.