The basis for the functioning of every organism is the energy that allows carry out their own chemical reactions of metabolism. Plants are autotrophic and obtain it from the sun, but heterotrophic organisms (animals) must obtain it in an already elaborated way. Metabolism allows the continuous use of available energy in small units.
All these reactions occur in the cell that make up the organisms. One of the metabolic processes is anabolism. Where, starting from simple molecules, it generates complex macromolecules that help in carrying out vital functions.
Meaning of anabolism in biology
The term has Greek origin. It is formed by the word ἀναβολή (anabolḗ). Consisting of the prefix “ana” (which means against or upwards), bole (action of throwing), and the suffix “ico” (system or relative to). is defined as the stage of metabolism, where biochemical synthesis reactions are carried out, in order to transform simple materials into more complex ones. Compounds are oxidized to form organic molecules.
In effect, it is the formation of other tissues through the consumption of energy. The product of anabolism gives rise to essential elements for the body. Occurs inside cells where enzymes participate and complement catabolism, which is the reverse process of anabolism. It is known in biology as constructive metabolism or biosynthesis.
Biological Anabolism Explained
Like all biological facts, the anabolism occurs in stages. The three stages are:
- Production of monosaccharides or simple sugars and amino acids. Fundamental components in proteins, among others.
- When activating the precursors, ATP (Adenosine triphosphate) is used for energy.
- Finally, large molecules originate, such as proteins, lipids, nucleic acids (DNA and RNA).
The energy needed by cells is obtained from sunlight, organic and other inorganic compounds. The process of anabolism according to the molecules that are synthesized gives rise to DNA replication, RNA synthesisof lipids, proteins, carbohydrates or sugars.
What are the hallmarks of anabolism?
The main characteristics of anabolism are:
- endergonic reactions occur, that is, requires or absorbs energy. Also of synthesis or construction and reduction.
- The energy produced is consumed by the body.
- Produces complex molecules from simpler ones.
- In animal cells it takes place in the smooth and rough endoplasmic reticulum and in the Golgi complex.
- For the plants takes place in chloroplasts.
- Among the hormones involved we have insulin (secreted by the pancreas), estrogen (from the ovaries). So too, that of the growth (produced by the pituitary gland) and testosterone (generated in the testicles).
- Use monomers to obtain polymers.
- It is not only caused during exercise, but also at rest. Where the body is recovering.
What functions does anabolism fulfill?
The functions that anabolism fulfills are:
- formation of tissues and cells, that is, it promotes the growth of all living beings.
- increase in muscle mass.
- Through the chemical bond in organic compounds accumulate energy, necessary for the vital functions of the body. Such as glycogen, triglycerides and starch).
How important is anabolism?
The two metabolic processes are anabolism and catabolism; and they are far-reaching for animal and plant entities. In this case, it is of paramount importance in sports. Because the reactions that take place there allow the strengthening of muscles and bones. Through this, the increase or decrease in body mass in athletes such as the abdomen, who practice bodybuilding and athletics, is explained.
Therefore, every person must consume the essential nutrients to produce enough energy. On the other hand, the muscles decrease it so the nervous system works first. However, the anabolic process is essential in plants, since they are organisms that manufacture their corresponding food, therefore, they are the first link in the food chain.
What types of anabolism are there?
According to the characteristics of anabolism, two types are distinguished: autotroph and heterotroph.
- The first is carried out in the cells that constitute the beings. able to make their own food or nutrients. They use simple molecules such as carbon dioxide (CO2), water (H₂O) and ammonia (NH3). It occurs in two modalities: photosynthesis and chemosynthesis.
- The second happens in any type of cell including autotrophs. Use what is obtained in catabolism, such as energy in the form of ATP and reduced coenzymes. It differs from the previous one, in that the precursor molecules are simple of organic origin, that is, the product of the decomposition of food and digestion.
heterotrophic anabolism
It is defined as an endergonic process, where chemical energy produced by ATP and reduced coenzymes is consumed. Occurs in the hyaloplasm or cytosol of the cell, which is the liquid part and ends in the Golgi apparatus or endoplasmic reticulum. Some anabolic reactions take the reverse route to the catabolic route. Thus, they take advantage of reversible changes. Among the main heterotrophic anabolic routes we have:
- Gluconeogenesis: is the process by which the body produces glucose from amino acids, fatty acids and lactate, compounds that do not have sugars in their constitution. At the cellular level it is produced in the mitochondria and in the cytoplasm and in organs such as the liver and in some cases in the brain and kidneys. By obtaining glucose with this route, it allows balancing blood levels due to limited food consumption, which can be generated by fasting or physical exercise.
- Gluconeogenesis: allows the synthesis of glycogen, which stores glucose in the body. It is found in the liver and muscles where it is broken down into glucose to provide the body with energy. This occurs when there is excess sugar. For example, after eating a large amount of carbohydrates.
- Lipid Anabolism: is the disintegration of fats, which are soluble in organic solvents and insoluble in water. These molecules are fatty acids, phospholipids, and steroids. They are used as a source of energy and in the main compounds of hormones.
- Protein anabolism: which is indispensable in the cellular structure and in the tissues of the organism. These are synthesized from amino acids. They are used as antibodies, enzymes, hormones and other components of cells.
- Anabolism of nucleic acids: These include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Are are macromolecules of cells They conserve genetic material important for protein synthesis. They allow the encoding, transmission and expression of the information provided by genes.
autotrophic anabolism
It is the process by which organic substances originate from inorganic compounds. They can be aerobic, that is, they require oxygen and another anaerobic where oxygen is not essential. It is carried out by plants, unicellular organisms and autotrophic bacterial entities. It is carried out through:
It is the process in which autotrophic beings They make their own food using sunlight. They are chemical reactions called Redox. Where electrons are transferred from an oxidizing compound to another molecule known as a reductant. It occurs in the leaves, in the chloroplasts, organelle present in plants and some algae. Although there are other algae and bacteria that do not have this structure, but do have photosynthetic pigments in their plasmatic membranes.
In photosynthesis two phases are distinguished; a luminous one in which thanks to sunlight the cell manufactures ATP and NADPH (Nicotiamide-Adenine Dinucleotide Phosphate) which allows carbon fixation in the Calvin cycle. It intervenes in all processes in which energy is required. ATP is considered the energy currency. In addition, in it the plant releases oxygen released into the atmosphere and that comes from the breaking of the water molecule. It takes place in the thylakoid structure of chloroplasts.
In short, the light phase of photosynthesis It is done in four stages:
- Sunlight absorption.
- The water rusts.
- NADP+ is reduced.
- The production of ATP.
Another phase is the dark (independent of light) or also called the Calvin Cycle, in honor of the scientist who studied it. Where the energy produced in the previous phase represented by ATP and NADPH is used to synthesize glucose from carbon dioxide that the plant absorbs from the atmosphere. Light is not necessary. It occurs in the stroma of chloroplasts. After several turns this phase produces a glucose composed of six carbons.
As for the process of capturing light energy with the pigments found in the thylakoid membrane, they bind to proteins that make up the antenna and They are responsible for capturing light and transport it to chlorophyll in the photosystems or reaction centers. There are two types: PS1 or photosystem I and PS II or photosystem II.
Like photosynthesis, it generates two phases. In the first, energy is absorbed from ATP and starting from reduced oxidation coenzymes from inorganic molecules such as nitrites, sulfides, ammonia and others. The second, the result of the previous phase allows to simplify the inorganic material to convert it into organic compound. Then carbon fixation occurs. Through the Calvin Cycle and thus obtain Glucose as a result.
It is similar to the dark phase of photosynthesis. It is typical of chemosynthetic bacteria. According to the compound that bacteria oxidize, there are different types, among which we have:
- Nitrogen chemosynthesis where ammonium is oxidized to nitrite or nitrate through nitrifying bacteria.
- Sulfur chemosynthesis whose result are reduced forms of sulfur obtaining sulfates. It is the sulfobacteria that are responsible for this.
- Bacteria called ferrobacteria found in fresh or salt water carry out the chemosynthesis of ferric oxide.
- Facultative autotrophs fix carbon resulting from organic compounds. Where are you oxidize molecular hydrogen in collaboration with hydrogenase enzymes.
Chemosynthesis plays a fundamental role for ecosystems, since through this anabolic route compounds are returned to the biogeochemical cycles. Necessary for living organisms to survive.
Examples of Anabolism
As already mentioned before, the photosynthesis carried out by plants in the production of food and nutrients through the use of sunlight where glucose is formed and oxygen is released. Without this process, plants could not be born, grow or reproduce, and life on earth would be in danger.
Another example of anabolism is the growth in humans as their weight and height increase, in the case of animals the increase in size. Also, the formation of proteins starting from amino acids. regeneration of organs, cells and tissues. In humans, the release of insulin, which is the hormone secreted by the pancreas, upon detecting that there is a high amount of glucose, activates the cells and thus accelerates the anabolic pathway.
In conclusion, all the biochemical reactions that are generated in organisms require the proper functioning of the use of energy and thus be able to disintegrate molecules and form new ones. This process is carried out through metabolism, which it can be with the anabolic or catabolic route. In the first, energy or ATP is used to synthesize molecules and produce new ones with more specialized structures and characteristics.
