Biochemical processes in the body
Biochemical processes in the body are based on the molecular structure of a substance, the atoms of which are connected by different bonds. In this case, the atoms of some substances carry a positive charge, others – a negative one. Under certain conditions that make possible the course of chemical reactions, the molecules of substances exchange their constituents (atoms or ions). As a result of the combination of atoms and molecules, thousands of new chemicals are formed. In this case, the impression can be created that the substances in the cell are in relative rest. However, the molecules of substances, like the characters of some secular ball, move in given directions, periodically exchanging partners with each other. When considering the functioning of a cell and its components (membranes, cytoplasm, organelles, nuclei), including the genetic apparatus from a biochemical point of view, all processes occurring in them are reduced to the rupture of some chemical bonds and the formation of others. This enables the cell to maintain its vital activity, receiving the energy necessary to maintain the life support subsystem, and performing specific functions. Biochemical processes are the basis of metabolism.
The ultimate goal of all biochemical reactions in the body is to perform two main functions. The first of them is to ensure the constancy of the internal environment (homeostasis), to directly maintain the stability of the “life support subsystem”. The second is the performance of special functions, consisting in responding to certain external influences (for example, a neuron conduction of a nerve impulse, hormone production, oxygen transfer by erythrocytes, muscle cell contraction).
Both of these tasks are accomplished using the feedback mechanism described in the previous section. Its essence lies in the fact that the cell remembers (often at the genetic level) the normal value of the parameter and changes the value of the current parameter until it reaches the normal one. In this sense, it is often impossible to say when and where the biochemical process began. You can only name the parameter that is being regulated and determine its normal value. How is metabolism realized?
In order for a substance to enter the cells, it must first enter the bloodstream. Only after that, having overcome a number of internal barriers, it will be able to reach the goal, contact target cells, cause the necessary changes in the functioning of tissues, organs and systems (which is a manifestation of its biological action) and, finally, having undergone transformations (biotransformation), or leave the body unchanged. In this case, as a rule, energy is released, in some cases – its absorption.
What are the ways in which nutrients can enter the bloodstream? From the gastrointestinal tract, nutrients penetrate into the bloodstream, which transports them throughout the body and delivers them to various tissues of organs and systems. This process is referred to as absorption (absorption). Upon receipt, proteins, carbohydrates and lipids are converted in the gastrointestinal tract with the participation of active enzymes that are secreted by the glands of the stomach, intestines, pancreas and enter the bile. When absorbed, substances pass through cell membranes, which play a major role in the transport of substances. It is their ion channels and pores (“gates” of the cell that structurally reflect the concept of functional inputs and outputs involved in performing the basic tasks of the cell.
