The microbiology is the science in charge of the study and analysis of microorganisms, living things small not visible to the human eye, also known as microbes. Microbes are those organisms that are only visible through the microscope: prokaryotic and simple eukaryotic organisms.
They can be made up of a single cell (unicellular), or of small cell aggregates formed by cells without cell differentiation.
However, traditional microbiology has dealt especially with the pathogenic microorganisms of bacteria, viruses, and fungi, leaving the other microorganisms for other branches of biology to study.
In this topic we will not deal with bacteria because we already studied them when we saw the prokaryote.
Biological music: Pathogens song.
Classification of microorganisms
Microorganisms are made up of a heterogeneous set of microscopic organisms, which can be acellular and cellular beings, prokaryotes and eukaryotes:
- Acellular microorganisms:
- Virus. They have a single type of nucleic acid (DNA or RNA ), a protein capsid and, some, a membranous envelope. Examples of viruses, HIV, influenza, etc.
- Prions. Made up of a single protein, such as the prion that causes Creutzfeldt-Jacob disease.
- Viroids. They are the smallest pathogens, consisting solely of circular single-stranded RNA without a capsid. For example, the viroid of the spindle tuber of the potato and those that cause diseases such as exocortis in citrus or cadang-cadang in coconut.
- Cellular microorganisms.
- Archaeobacteria (Domain Archaea). Adapted to living in environments with extreme characteristics of temperature, pH ... For example, the halophilic bacteria of the Dead Sea
- Eubacteria (Bacteria Domain) :
- Bacteria. They can be autotrophic beings (photo or chemosynthetic) or heterotrophs (saprophytes, symbionts or parasites). Example, Salmonella , Escherichia coli , ... They can be aerobic or anaerobic (like Clostridium).
- Cyanobacteria. They carry out oxygenic photosynthesis. By endosymbiosis, they are the origin of chloroplasts. For example, Anabaena, which lives in symbiosis in the Azolla water fern.
- Eukaryotes (Domino Eukaria):
- Flagellated. Unicellular, they move through flagella. For example, Trypanosome.
- Ciliates. Unicellular, they are moved by cilia. For example, Paramecium.
- Rhizopods. Unicellular, they move through pseudopods. For example, Amoeba.
- Sporozoans. Unicellular, they do not move. They are parasites. For example, Plasmodium.
- Yeasts: Unicellular. They are divided by budding. For example, Saccharomyces cerevisiae, useful in making bread, beer and wine.
- Molds Multicellular filamentous fungi. For example, Penicillium.
- Green algae. Unicellular, photosynthetic, green in color. For example, Volvox.
- Red algae. Unicellular and multicellular, with reddish pigmentation. For example, Bangia.
- Diatoms. Unicellular, they constitute phytoplankton, they have a silica cell wall.
- Dinoflagellates. Almost always unicellular, with flagella.
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