Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.
| Column I | Column II |
| (A) Glycosidic linkage | (a) Monomeric units of nucleic acids |
| (B) Peptide bond | (q) Sugar-heterocyclic base combination |
| (C) Nucleoside | (r) Linkage between two amino acid units |
| (D) Nucleotide | (s) Linkage between two monosaccharide units |
Answer & explanation
Correct answer: option 2
(A) The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through an oxygen atom is called glycosidic linkage.
(B) In organic chemistry, a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein chain.
(C) A nucleoside consists of a nitrogenous base covalently attached to a sugar (ribose or deoxyribose) but without the phosphate group.
(D) Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth.