Overview of metabolism; concept of flow of matter and energy; thermodynamics of coupled systems and non-equilibrium reactions;  biological energy currencies: high energy bond, reducing power and inter conversions of energy forms; carbon, nitrogen cycles in biosphere; classification of living system based on carbon and energy requirements; methods to study metabolism; carbohydrate and lipid catabolism; glycolysis; TCA cycle; fatty acid oxidation, other metabolic routes of carbon; oxidative phosphorylation; biosynthesis of carbohydrates and lipids photosynthesis; photosynthetic electron transport; Calvin cycle and other avenues of harvesting light energy; gluconeogenesis; Cori cycle; glycogen metabolism; biogenesis of fatty acids and sterols; nitrogen metabolism: sources of organic nitrogen; flow of nitrogen into biosynthesis and catabolism of amino acids; central role of glutamine; purines and pyrimidines; the metabolism of nucleotides; urea cycle and excretion of nitrogen; integration of metabolism and concepts of metabolic regulation.