Metabolism refers to a multifaceted biochemical process happening within our bodies at cellular level. It is a complex mechanism and involves concurrently happening processes like anabolism and catabolism through an array of metabolic pathways. Anabolism involves the formation of newer molecules while catabolism is the break up of larger molecules into smaller ones and is the one responsible for production of energy necessary for activities of the cells.

Metabolic pathways involve many chemical reactions in a sequence happening inside the cell which are being initiated and speeded by the actions of enzymes. Nutrients in the food help the enzymes to execute their task. Within the cell there can be numerous metabolic pathways creating a metabolic network. So, metabolism is a complex mechanism involving several metabolic pathways in an intricate cycle.

In order to better understand about metabolic pathway one needs to study the different types of metabolism namely, carbohydrate metabolism, protein metabolism, fatty acid metabolism and the nucleic acid metabolism. These different types of metabolism occur within various organ systems in the body and perform several activities.

Therefore, metabolism involves anabolism and catabolism occurring simultaneously. But, there is a difference in the rates of anabolism and catabolism to enable the formation of energy for other purposes of the body. When anabolism rate is higher, there is improvement in the growth of cells in the body which is reversed if the rate of catabolism is higher.

For example, sugar level in the body is regulated by the carbohydrate metabolism through various metabolic pathways. By this process, sugar is not only broken down, it gets converted into metabolites that can be used by the body to perform many activities. One such pathway involving carbohydrate metabolism is in the liver where glycogen is reduced from a polysaccharide to monosachharides.

The glycogen gets converted into glucose that enters the blood stream. Prior to the glucose reaching the blood stream, carbohydrate metabolism involves the conversion of glycogen into glucose phosphate ions which can be lethal to the cells of the blood. For this reason, the pathway of carbohydrate metabolism takes place within the liver where the phosphate ions are then getting converted into glucose that can reach the blood.

In the same manner, fatty acid metabolism involves the two processes, anabolism and catabolism. This helps in the generation of energy that is very essential to the smooth functioning of the body. The fatty acids are also useful in protein metabolism.

Phospholipids, which are fatty acids get stored within the cell membrane during metabolism of proteins. Protein molecules are converted to essential amino acids that are again essential in the metabolic pathway to form additional acids as part of the Krebs cycle which is a vital portion of the metabolic pathway.

These amino acids and many other compounds get blended with the blood plasma. Protein metabolism thus generates the formation of amino acids that helps in providing energy to the body. Nucleic acid metabolism too follows specific metabolic pathways to produce energy.