What is metabolism?
It is called metabolism for a set of chemical reactions, by which all living things can change the nature of certain substances to obtain the number of nutrients and energy that are needed for the processes of growth, development, reproduction, and sustenance of life. it occurs.
Metabolism occurs inside the cells of organisms, called enzymes, through a group of organic materials responsible for promoting certain reactions. In the case of the human body, these substances are secreted by the liver.
Enzymes seek to produce chemical reactions that are favorable to the body, while at the same time inhibiting unfavorable ones, through specific chains of reactions called metabolic pathways, in which a substance is transformed into a chemical that in turn forms a new one. Feeds the process. Changes, isolating compounds that consider metabolism to be nutritious, from those that consider it toxic and should be discarded.
Very different species of living things use the same metabolic pathways, although each specific metabolism will also determine the amount of food that the species needs.
Phases of metabolism
Biological metabolism is made up of two phases or conjugated phases, known as catabolism and anabolism. The first deals with the release of energy with the breaking of the given chemical bonds; The second is the use of this energy to form new chemical bonds and to form new organic compounds. These phases depend on each other and react to each other.
- Catabolic or destructive metabolism. Energy-release processes, usually through degradation and oxidation, transform complex molecules into simple ones, by the breakdown of the chemical bonds present in the nutrients. And in turn, obtaining chemical energy (ATP), reducing power (the ability to donate electrons or receive protons from certain molecules), and the components required for anabolism.
- Anabolic or creative metabolism. Manufacturing processes that consume chemical energy reverse the process of catabolism, thus forming more complex molecules from simpler structures, and supplying the body with proteins, lipids, polysaccharides, or nucleic acids.
A metabolism is a group of chemical changes that provide the living body with the substances it needs to exist, grow, and reproduce. In the case of plants and autotrophic organisms, metabolism serves to fix carbon and use sunlight or chemical energy from external sources, from simple molecules, to synthesize sugars that later serve as cellular fuels. Will do.
On the other hand, in heterotrophic organisms, such as animals, metabolism begins with oxidation and decomposes the glucose (glycolysis) extracted from the organic material on which they feed, which requires digestion that feeds the tissue and the consumed substance. Transforms into their primary components.
Importance of metabolism
Metabolism is a guarantee of life. Living beings are exchanging matter and energy with the environment throughout life, so that metabolism can remain with us from birth to death, to function without interruption.
If metabolism were to be inhibited, death would be ensured, as it would be impossible to continue to obtain the chemical energy to maintain vital activity, much less to grow or regenerate or replace damaged tissues.
Types of human metabolism
According to nutrition and food experts, three types of human metabolism can be identified, which are:
- Protein Metabolism. Short of sugars and sweets, they show a precursor to a diet rich in protein and animal fat and often starve. Carbohydrates are not good for them.
- carbohydrate metabolism. On the other side of the coin, they are people with a moderate appetite who like sweets and flour, as well as stimulants (such as coffee), and who make frequent weight changes, making it difficult for them to reach certain consistency.
- Mixed Metabolism. An intermediate category between protein and carbohydrates, it is equally nourished by both forms and is usually kept within a middle-class appetite. However, when feeding fails, they are the first group to show signs of fatigue.
What is metabolism pathway?
Metabolism and metabolic pathways
- Metabolism, also known as metabolism, is the general term for all chemical changes in organisms. Metabolism is the dynamic part of biochemistry and the basis for the existence of biomolecules.
- Metabolism is one of the basic characteristics of life, including anabolism and catabolism. The former is also called assimilation, which means that the body takes nutrients from the environment and converts them into its components; the latter is also called dissimilation, which means that the body converts its substances into metabolites and excretes them from the body. The two are complementary to each other. Their balance allows the organism to maintain its stability and constantly update to adapt to the environment.
- The metabolic process from one metabolite to another metabolite is achieved through a series of continuous enzymatic reactions. A group of interconnected enzymatic reactions that complete a certain metabolic process is called metabolic pathways. The forms of metabolic pathways are diverse, including linear, branched, and circular. Circular metabolic pathways will have entrances and exits.
- There is no completely reversible metabolic pathway. The synthesis and decomposition of some substances are two completely different metabolic pathways (such as fatty acid metabolism); the metabolic pathways of other substances contain partial irreversible reactions (such as sugar metabolism). These irreversible reactions usually release energy during catabolism and generate ATP; during anabolism, more energy is required to promote the reaction. This often requires completely different reaction mechanisms and completely different enzymes.
- The metabolic pathways have a definite cellular location. Enzymes have a certain distribution area in the cell, so every metabolic process is carried out in a certain area. For example, glycolysis proceeds in the cytoplasm, the tricarboxylic acid cycle proceeds in the mitochondrial matrix, and oxidative phosphorylation proceed in the inner mitochondrial membrane. This can increase the concentration of local metabolites and prevent different pathways from interfering with each other.
- Even if the reactions are carried out in the cytoplasm, different metabolic pathways are separated. Some enzymes are reversibly bound to specific membrane structures, and some enzymes are concentrated on the surface of some particles. For example, enzymes related to glycogen metabolism generally gather on the surface of glycogen particles to catalyze reactions.
- Enzymes in the cytosol are not evenly distributed. Under certain conditions, some enzymes can gather to form droplet-like complexes, which are separated from the surrounding water environment and exchange continuously. This phenomenon is called phase separation. Phase separation can regulate enzyme activity, thereby regulating metabolic flux (Biomolecules. 2018 Dec 3; 8(4). PII: E160.), and can also participate in a variety of physiological and pathological processes, such as chromatin structure, transcription regulation, and neurodegeneration Sexual diseases and so on.
- The metabolic pathways communicate with each other. The various metabolic pathways can cross each other through common intermediate metabolites, or they can be connected through transition steps. In this way, various metabolic pathways are connected to form a complex metabolic network. Through the network, the metabolism of various substances can be coordinated, and certain substances can also be transformed into each other.
- There is an energy connection between metabolic pathways. Generally, anabolism consumes energy, and catabolism releases energy. The two are connected by high-energy compounds such as ATP as energy carriers.
- The flow of metabolic pathways is adjustable. The body needs different metabolic rates in different situations to provide the right amount of energy or metabolites. This is achieved by controlling the flow of material metabolism. Because metabolism is an enzymatic process, organisms coordinate and control the flow of various metabolic pathways by controlling the activity and quantity of enzymes.
- The flow of each metabolic pathway is limited by the step with the slowest reaction speed. This step is called the rate-limiting step, and this enzyme is called the rate-limiting enzyme. The rate-limiting step is often the first step in a metabolic pathway or branch, to avoid the accumulation of harmful intermediates. The rate-limiting step is generally an irreversible reaction, and the reverse process is often catalyzed by another enzyme.
- The activity and quantity of rate-limiting enzymes are often regulated by multiple mechanisms. From the perspective of metabolic pathways, feedback inhibition is the most common, that is, the accumulation of metabolites inhibits enzyme activity. Other types of regulation also exist, such as feedforward activation, feedback activation, and so on.
What is metabolism? and What is metabolism pathway?