Aquaporins are protein ion channels that facilitate the transport of water. Thus, chemically they are polypeptide in nature.
Asparagine is an amino acid with −CONH2 group in the side chain. Thus, it is chemically an amide.
Chitin is a mucopolysaccharide of the monomer N−acetylglucosamine. It is found in the cell wall of fungi and in the exoskeleton of arthropods.
Abscisic acid (ABA), synthesised in response to water stress, is an apocarotenoid.