The sum of all chemical reactions within a living organism is known as Metabolism. Biochemical pathway that functions in both anabolism and catabolism are called amphibolic pathways, meaning that they are dual purpose. The energy of catabolic reactionsisusedtodriveanabolicreactions. The energy for chemical reactions is stored in ATP. The chemical reactions are catalyzed by different enzymes. Enzymes catalyze chemical reactions by lowering the activation energy. Most of the cells energy is produced from the oxidation of carbohydrates. During respiration organic molecules are oxidized. Energy is generated from the ETC. In aerobic respiration, O2 function as the final election acceptor. In anacrobic respiration, the final electron acceptor is an inorganic molecule NO2-, SO42- other than O2.
Complete oxidation of glucose molecule takes place in 3 sequential reactions.
• Glycolysis occurring in cytoplasm
• Krebs cycle occurring is mito chondrial matrix
ETC (Oxidative Phosphorylation) occurring is inner mitochondrial matrix. In aerobic prokaryotes, 38 ATP molecules can be produced from complete oxidation of a glucose molecule in glycolyins, krebscycle, and ETC. In eucaryotes 36 ATP molecules are produced from complete oxidation of a glucose molecule. In incomplete oxidation of glucose molecules will revolt in fermentation, O2 in anaerobic condition. Various commercial products are produced from pyruvic acid. Lipid can be catabolised by lipase which hydrolyze lipid into glycerol and fatty acid. Then fetly acids are catabolised by Beta oxidation. Proteins can be catabolised by Deamination and Transamination process into amino acids. Carbohydrate, Fat, Protons can all be the source of electrons and protons for respiration. Microbial enzymes are extensively used in food processing, preservation, paper industry and in scientific research.