Metabolism is a rather complicated process. It is characterized by the implementation of the transformation in the body of chemical components. This process contributes to the activity, growth, development and life of the organism as a whole. Engels, characterizing the metabolism, said that this is the main sign of life, and noted that with the cessation of the process, life will stop. During the conversion of chemical components, the energy necessary to ensure vital activity is generated.
Metabolism, as you know, consists of two opposite processes that occur at the same time.
Dissimilation (catabolism) includes reactions caused by the breakdown of products, their oxidation and subsequent excretion of the components of the breakdown. Assimilation (anabolism) implies all reactions that are associated with the synthesis of the elements necessary for the body, their assimilation and use for development, growth, and vital functions.
Metabolism is a complex of energy and biochemical processes that provides the use of food components for the needs of the body, satisfies its needs in energy and plastic products.
In the digestive system, substances (carbohydrates, fats, proteins and other high molecular weight compounds) are broken down into simpler compounds (low molecular weight). After penetration into the blood and tissues, the latter undergo subsequent transformations: oxidative phospholation, aerobic oxidation, and others.
It should be noted that in every living organism various biochemical processes occur. Moreover, in non-living bodies there is no substitution of atoms and molecules, their components.
When conducting studies with the introduction of labeled atoms into animals, it was found that metabolic processes in all cells and tissues occur continuously. In this case, no restrictions were found between the "energy" and "building" molecules. Their movement equally constitutes the main metabolism.
It was found that on average in humans, half of all tissue proteins change every eighty days. Liver enzymes (this organ is characterized by the presence of the most intense reactions) are updated every two or four hours. There are some elements that are updated every few tens of minutes.
Exchange processes provide a dynamic balance to a living organism as a system. At the same time, the processes of synthesis and destruction, death and reproduction are balanced. Improper metabolism is accompanied by an imbalance. This, in turn, leads to a disruption in the activity of systems and organs.
The basis of metabolic reactions is the interaction of molecules and atoms at the physico-chemical level. This relationship is subject to uniform laws for inanimate and living matter.
Exchange processes are inextricably linked with the exchange of energy. Living organisms are considered open systems (from an energy point of view). Depending on the environment surrounding the body, energy is formed inside it (the body). Thus, existence is ensured under the condition of continuous supply of energy from outside.
For humans and animals, the primary energy source is solar radiation. Thanks to its effect, food is also formed.
Food has a diverse and complex composition. Most of it contains the main nutrient components - macronutrients. These include carbohydrates, fats, proteins. Mineral components (macronutrients) are also present in food. These include sodium, phosphorus, calcium and others. Micronutrients are also present in food: selenium, manganese, iodine, zinc, cobalt, copper and others. Together with vitamins, trace elements belong to the class of micronutrients.