AP BIOLOGY

Detailed explanation-1: -Tannins are complex chemical substances derived from phenolic acids (sometimes called tannic acid). They are classified as phenolic compounds, which are found in many species of plants, from all climates and all parts of the globe.

Detailed explanation-2: -Tannins are, after lignins, the most abundant source of natural aromatic biomolecules and can be an alternative feedstock for the elaboration of chemicals, building blocks to develop polymers and materials. Tannins are present in all vascular and some non-vascular plants.

Detailed explanation-3: -Characteristic examples of hydrolysable tannins are (1) gallic acid; (2) hexahydroxydiphenic acid; (3) ellagic acid; and (4) pentagalloylglucose, which contain a central glucose molecule as the core attached with multiple gallic acid units, while ellagitannins are associated to hexahydroxydiphenic acid.

Detailed explanation-4: -Tannins are polyphenolic metabolites commonly found in higher plants. Tannins are considered secondary metabolites as they are not directly involved in growth, development, or reproduction (Herderich and Smith 2005).