
Glycosidic bond: When a base (Purine or pyrimidine) is attached to D-ribose or deoxyribose, is formed nucleoside.A nitrogen atom at 9th position of Purine base and nitrogen atom at 1st position of pyrimidine base is linked to carbon 1st position of deoxyribose or ribose by N-glycosidic linkage.
Peptide bond: A peptide bond formed between two two amino acids.
Phosphodiester bond: In polynucleotide molecule, two adjacent nucleotides are liked through a phosphodiester bond.