- Carbohydrates are synthesized through photosynthesis in plants and gluconeogenesis in animals. Glucose is the main fuel for most organisms. - Carbohydrates exist as monomers, dimers, oligomers and polymers. Monomers include glucose and fructose. Polymers serve structural and storage functions. - Carbohydrates can exhibit different structural isomers including anomers, epimers and cyclic/acyclic forms which impact their properties. Abnormal carbohydrate metabolism can cause diseases like diabetes.

18. Epimers

19. Isomers of D-Aldoses

20. Isomers of D-Ketoses

23.  -D-Glucose  -D-Glucose +  -D-Maltose  -1-4 G-linkage  -D-Galactose  -D-Glucose +  -D-Lactose  -1-4 G-linkage Sucrose  -D-Glucose  -D-Fructose  -1-2 G-linkage Disaccharides are Glycosides

24. Disaccharides are Glycosides