The keyword metabolism has its roots in the Greek term connoting overthrow or change. Metabolism refers to a multifaceted biological and biochemical process. All organisms must under metabolism to survive. Metabolism involves the cells and the living organisms in our body. Metabolism metamorphoses the compounds that are basically chemical in nature. It was way back in 1614 that details of the maiden experiments (under controlled state) were brought out in black and white. It was Santorio Santorio's tome Ars de statica medecina.

Immediately after the publication, he became famous across Europe. In the book Santorio explains in detail his series of pain-staking and time-consuming experiments. First, Santorio used a steelyard balance. Next, he suspended a chair to it. Then, he sat on the chair and had the weight taken and recorded during several stages. The situations were prior to having a meal and again after finishing it; while sleeping; as well as when he was working, having sex, and even while undergoing a fast. What is more, Santorio recorded his weight when he was deliberately not taking any alcohol and above all as he was excreting. The findings were startling. Santorio discovered that he lost the lion's share of the food that he taken in perspiration that was insensible (perspiratio insensibilis). Metabolism engages a complex set of intricate methods like anabolism, catabolism via the metabolic pathways. Anabolism is that progression when complex molecules (basically organic) undergo biosynthesis. Catabolism is the breakdown of these molecules. Metabolic pathways are the procedures taken by the enzymes in pre-determined sequential mode. Total metabolism points to an organism's biochemical processes. Cell metabolism means the chemical moves within each cell.

Metabolism has been classified into carbohydrate metabolism, fatty acid metabolism, protein metabolism, and nucleic acid metabolism. Carbohydrate metabolism proceeds via several pathways to control our sugar levels, degrade the sugar, and convert these items into different metabolites so that our bioenergetic processes keep on functioning smoothly. Here's an overview of how the process gets going within our liver. Glycogen, a polysaccharide, is broken down in the liver. This polysaccharide is transformed as glucose, and then mixed with our blood. Mentionably, prior to the releasing of the glucose into the blood system Carbohydrate metabolism breaks down glycogen into the ion, glucose phosphate. This ion has the potential to even destroy the blood cells. Hence, Carbohydrate metabolism takes the necessary precautions by taking the help of an enzyme which gets rid of the phosphate, and thereby ensures that only pure glucose is released into the blood. This enzyme is located within the endoplasmic reticulum membrane.

Fatty acid metabolism biologically produces energy from the carbon and fatty acid sources that we take. Fatty acid metabolism takes place via a two-fold process, viz., catabolic and anabolic. The former produces primary metabolites as well as energy from the fatty acids. The latter gives birth to vital molecules again from those fatty acids. Therefore, fatty acids are vital compositions of our body system. Fatty acids like proteins or carbohydrates and Triglycerides are also necessary to modify the proteins. Mentionably, the steroid hormones are also extracted from the fatty acids. Two fatty acids are stored in each cell membrane composed of phospholipids. Protein catabolism breaks down the proteins and transforms them into the important amino acids. These amino acids are then used to create more such acids as per the Krebs Cycle.

The transformed amino acids and other simple compounds are then allowed to enter plasma membrane. It is within the membrane that protein metabolism mixes them with ribosomes and RNA ribonucleic acids. Thus, protein metabolism takes forward the complex polymerization process and changes the broken down amino acids into proteins that are virtually the energy generators of our body.

Nucleic acid metabolism produces the necessary inputs that generate energy. Nucleic acid metabolism is similar to the synthesis process of lipids and polysaccharides. Nucleic acid metabolism forms the proteins and nucleic acids from their primary raw blocks. First, the process eliminates the inorganic pyrophosphate and carries forward a very complex process to form the nucleic acids from nucleoside triphosphates.