A carboxyl group can be described as a functional group. It is comprised of a carbon atom bonded to an oxygen atom, which is bonded to a hydroxyl group. This group contains various compounds, including acyl compounds and carboxylic acid derivatives. The carboxyl group is important in biochemistry as it is involved in a variety of biochemical reactions. The carboxyl group can be found in both ethers and esters. Ethers are compounds that contain a carbon-oxygen-carbon bond, while esters contain a carbon-carbonyl-oxygen bond.