Biomolecules — BIOLOGY STD 11 Science — Question

Nature of bond linking monomers in a polymer. Glycosidic Bond: A glycosidic bond is a certain type of functional group that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. Peptide Bond: A peptide bond (amide bond) is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amine group of the other molecule, thereby releasing a molecule of water (HO). This is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids. The resulting CO-NH bond is called a peptide bond, and the resulting molecule is an amide. The four-atom functional group -C(=O)NH- is called an amide group or (in the context of proteins) a peptide group. Polypeptides and proteins are chains of amino acids held together by peptide bonds, as is the backbone of PNA. Polyamides, such as nylons and aramids, are synthetic molecules (polymers) that possess peptide bonds.
Phosphodiester Bond: A phosphodiester bond is a group of strong covalent bonds between a phosphate group and two other molecules over two ester bonds. Phosphodiester bonds are central to all life on Earth, as they make up the backbone of the strands of DNA. In DNA and RNA, the phosphodiester bond is the linkage between the 3' carbon atom of one sugar molecule and the 5' carbon of another, deoxyribose in DNA and ribose in RNA.