Carbon can form chains with carbon atoms bonded together in linear forms . Carbon can also form branched chains and cyclical molecules . So hydrocarbons do not readily dissolve in aqueous solvents. Simple hydrocarbons are not very important in familiar biological chemistry. But many biological molecules are modifications of hydrocarbons, which include other atoms or functional groups.
Sugars are poly-alcohols and so are very soluble in water.
The electronegativity of the oxygen polarizes this bond and increases water solubility. There are two major types of carbonyl compounds in biological molecules. There are also several classes of C-N bonds. There are many thousands of biologically synthesized amino acids, but only twenty are routinely found in proteins. The most common amide groups are the peptide bonds between consecutive amino acid residues in polypeptides.