Carbohydrates, lipids, proteins (levels of organization), and nucleic acids. what basic role (s) does each type of molecule play in a cell or a living organism?

Glycosidic bonds, Peptide bonds, Ester linkages & phosphodiester bonds respectively.

Two carbohydrate molecules are connected by glycosidic bonds.

A glycosidic bond means, a connection between 1st and 4th carbon atoms of two adjoining monosaccharide molecules. In this process a H2O molecule dissociates.