The chemical reactions that take place in aerobic cell respiration are subject to a process of molecular transformation. This process is known as the Krebs cycle or citric acid cycle. It is a metabolic pathway in which a series of chemical reactions occur consecutively.
A complex process in cellular terms
The molecular transformation process takes place in the mitochondria of aerobic cells, that is, those that have oxygen.
When glucose enters the cell, it goes through a process called glycolysis. From this moment the Krebs cycle begins properly. In a first phase, glucose is transformed into pyruvate (this organic compound is decisive in metabolism ), which in turn becomes acetylcoenzyme (the enzyme that transforms pyruvate into acetylcoenzyme is pyruvate dehydrogenase).
In this process of molecular change, dehydrogenase uses a series of substances: thiamine or vitamin B1, vitamin B2 or FAD, vitamin B3 or NAD, vitamin B5 and lipoic acid.
Once acetylcoenzyme is formed, it joins a new molecule to form citrate. In the next phase, alpha ketoglutarate is formed from the intervention of an enzyme, isocitrate. Alpha ketoglutarate reuses the same five substances used in the pyruvate phase.
All these reactions allow the elimination of Co2 and this makes the cells of a living organism can perform the function of breathing. In this sense, the Krebs cycle helps us to understand the concept of metabolism.
All systems in the human body have a metabolic activity
In this sense, the body’s cells exchange matter and energy to maintain, repair or reproduce cell structures. This molecular transformation process is known as metabolism.
Metabolism is divided into two phases: anabolism and catabolism. In the first, the body’s cells obtain micronutrients that join together and create macronutrients (proteins, carbohydrates and fats). In catabolism there is a process of destruction where the body breaks down the various macronutrients into simpler molecules.
the role of glucose
In addition to the complexity of the molecular processes that are present in the Krebs cycle, this process can be understood as one that allows us to perform vital functions that require a certain amount of energy, such as walking, running or working.
It is worth remembering that this process begins precisely with the action of glucose, from which the fruits, honey and starch found in rice, pasta and potatoes come from. When a person ingests a high amount of glucose and does not exercise enough, it is very likely that cholesterol appears in the blood.