definition of microorganisms

Microorganisms are the smallest living things that can only be seen through a microscope. In this extensive group we can include the viruses, bacteria, yeasts and molds that swarm the planet earth..

In respect of their biological structure and unlike what happens with plants or animals, this is extremely elemental since they are unicellular, in what they do coincide with those mentioned is in the individuality that they present and display.

Some microorganisms can be responsible for the deterioration of some foods, even causing serious diseases to those who consumed those foods infected with unhealthy microorganisms, but paradoxically and on the other hand there are other microorganisms that are widely beneficial and are purposely used in the preparation of some foods in order to extend their lives or to change their propertiesSuch is the case of the fermentation that takes place when manufacturing products such as cheeses, yogurts and sausages.

Those pathogenic microorganisms, that is, those that cause serious consequences and damage to health, when under water are differentiated into three categories: bacteria and viruses that can be found in both surface and groundwater and protozoan parasites that only they are found in surface waters.

Different microorganisms

Bacteria are the most abundant organisms in nature and they inhabit all types of environments, including our own body. Some of them are harmful to health and cause disease (for example, the tuberculosis bacteria). However, others are beneficial (some generate the intestinal flora of the human body).

Protists grow and move in various ways. Some are typical of the aquatic environment, others live as parasites in other living beings (an example of a protist is the amoeba, which lives in fresh and clean waters and under aquatic plants but can also live in the digestive tract of other living beings) .

Microscopic fungi are generally single-celled and are used in making breads, pizzas, cheeses, and alcoholic beverages (yeast is probably the best known). Some fungi are used to make drugs, such as penicillin, the antibiotic that kills bacteria and prevents them from continuing to grow.

The special case of viruses

Viruses are a specific type of parasite. They are considered acellular beings, since they do not have the properties of eukaryotic or prokaryotic cells. Furthermore, they cannot perform functions autonomously. In terms of its structure, it is made up of genetic material and a protein envelope called a capsid. Their size is smaller than that of bacteria and they are not visible under the light microscope.

With respect to their classification, they can be ordered according to the type of nucleic acid and there are four classes of viruses: single-stranded DNA, double-stranded DNA, single-stranded RNA and double-stranded RNA. In relation to the shape of the capsid, they can be cylindrical or elicoidal (like the tobacco mosaic virus) or icosahedral (also known as mixed).

Of course each of these and through them, are widely prone to the installation of some type of infection in the living beings that inhabit

Due to their acellular condition, viruses need a cell that serves to host them. From this phenomenon, the virus replication process is possible in the following phases: the first step is the entry of the virus into the cell and the injection of nucleic acid, in the next phase protein synthesis occurs, then the viral nucleic acid and the assembly and finally the liberation of the viral particles that have been formed takes place.

Bacteria, for example, are less persistent in damage than protozoites since their persistence is less than that of the latter.

The very old, the young and the sick are the human beings most easily attacked by these, since their immune system is weakened, they can multiply to piaccere.

Likewise, it is not impossible for the infection to spread to other beings that do not fall into the aforementioned groups, as a consequence of direct contact with the mucosa and secretions of the infected by any of these microorganisms.

Photos 2 and 3: iStock - KuLouKu / kasto80