Metabolism is an integral component of the life of the body. It includes several processes. Energy metabolism involves the breakdown of organic substances and the release of energy from chemical compounds and bonds. It is noted that its further distribution is carried out partly in the form of heat. The other part is reserved in ATP molecules.
Stages of energy metabolism in animals
The first stage is preparatory. Energy metabolism begins with the penetration of food into the human or animal organism in the form of complex macromolecular elements. Before penetrating into tissues and cells, these compounds are destroyed to low molecular weight.
Hydrolytic decomposition of organic substances is carried out with the participation of water. This process takes place in the digestive tract (in multicellular organisms), at the cellular level (in lysosomes), in the digestive vacuoles (in unicellular organisms) under the influence of certain enzymes.
Proteins in humans and animals are split in the duodenum and stomach to amino acids. This process occurs under the influence of peptide hydrolases (chemotrypsin, trypsin, pepsin). Even in the oral cavity, the process of splitting polysaccharides begins. The ptyalin enzyme takes part in this. Further cleavage of polysaccharides occurs under the influence of amylase in the duodenum. It also splits fats. This process is affected by lipase. The energy that is released after this is distributed in the form of heat.
Energy metabolism includes the entry of nutrients into the bloodstream and their transportation to all cells and organs. In cells, they penetrate directly into the cytoplasm or lysosome. In the event that substances are cleaved in the lysosomes at the cellular level, then they are immediately delivered to the cytoplasm. This step involves preparing the compounds for intracellular cleavage.
In the second stage, energy exchange is anoxic oxidation. The processes occur without oxygen, at the cellular level. Oxidation takes place in the cell cytoplasm. One of the key elements providing energy metabolism is glucose. Other organic compound (amino acid, glycerol, fatty acids) are included in the process of transformation in different stages.
The breakdown of glucose without oxygen is called glycolysis. This compound undergoes several successive transformations. First, its conversion to fructose occurs. Glucose phospholates - it is activated under the influence of two ATP molecules, turning into fructose diphosphate. The field of this is the decay of a hexatomic carbon molecule into two tri-carbon glycerophosphate molecules. As a result of several reactions, they are oxidized. In this case, the molecules lose two hydrogen atoms, eventually turning into pyruvic acid molecules . The result of these reactions is four synthesized ATP molecules. Since two ATP molecules were used for the initial activation of glucose, 2ATP is generally formed. Thus, the energy released during glucose breakdown is partially reserved and partially released in the form of heat.
In the third stage, respiration occurs (biological oxidation). This stage is possible only under the influence of oxygen. In this regard, it is called oxygen. This process takes place in the mitochondria.
Under conditions of a general (main) exchange, energy costs (on average) for an adult are about 24 kcal / kg / day. When calculated per average person, daily consumption is 1,500 kcal for women and about 1,700 kcal for men. In patients with a different profile of pathology, the need for energy per day may increase two to three times.