The bacteria are microorganisms formed by a single cell . These are forms of life so small that they cannot be seen with the naked eye and that they carry inside what is necessary to interact with the outside and satisfy their needs. Their sizes vary in the order of micrometers , which are equal to one millionth of a meter (1 * 10 -6 m = 0.000001 m). They are the most abundant living beings on the planet and can exist in any habitat, whether terrestrial or aquatic.
Depending on the conditions of a place, it will be the type of bacteria that inhabit it. In addition, by carrying out their natural processes such as respiration or feeding , they will be fulfilling biological functions for their environment. Some of them are found within the human body and regulate important mechanisms such as the digestion of food. This turns the bacteria into active agents in the environment where they grow.
Types of bacteria
These single-celled organisms have such a complex variety that they are classified according to several criteria:
- Its morphology (shape of its cell).
- Their functions on the planet.
- Their feeding.
- Your breathing.
- The temperature at which they survive.
According to their morphology , bacteria are classified into:
- Coconuts: they are shaped like a sphere.
- Diplococci: two joined spheres.
- Streptococci: they are spheres in a linear chain.
- Staphylococci: they are spheres joined in an irregular way, like a cluster.
- Bacilli: they are shaped like elongated rods.
- Streptobacilli: rods in a row, point to point.
- Cocobacilli: Neither as spherical as a coconut nor as elongated as a bacillus.
- Helicoidal: Forms twisted in themselves.
- Spirals: they are helical in the form of rigid spirals.
- Spirochetes: they are helical in the form of flexible spirals.
- Vibrios: Helical (curved only) shaped like a bean.
Depending on their functions on the planet there may be:
- Nitrifying agents: they feed by oxidizing inorganic nitrogen compounds.
- Photosynthetic: are those that use carbon dioxide from the environment and sunlight to produce glucose as a source of their own energy.
- Chemosynthetic: from chemical substances, they make their nutrients.
Depending on their diet or nutrition, bacteria can be:
- Autotrophs: they generate their own food using resources such as sunlight, in the case of photosynthesis.
- Heterotrophs: they feed on other living beings, where there is accumulated organic matter, taking advantage of it and decomposing it until the nutrients are available for other forms of life.
- Saprophytes: they are heterotrophs that feed on dead organic matter. They are used in wastewater treatment plants for biological treatment.
Depending on your breathing , the bacteria can be:
- Aerobic: they live in environments with sufficient oxygen in the air. It is especially appreciated in water that receives sunlight and constant evaporation for the air to penetrate.
- Anaerobic: are those that can live only in environments without oxygen. They are bacteria that live in stagnant waters, such as those in swamps, in which decomposition gases such as hydrogen sulfide (H 2 S) and methane (CH 4 ) abound .
- Facultative: they are able to adapt and survive in environments with little or enough oxygen.
Depending on the temperatures at which they can develop and survive, bacteria can be:
- Psychrophilic or cryophilic : they begin to grow in population between – 5 ° C and 5 ° C. Obligate psychrophiles have an optimal temperature between 15 ° C and 18 ° C. The facultative psychrophiles or psychrotrophs have it between 20 ° C and 30 ° C.
- Mesophilic : they have optimal temperatures for their development between 25 ° C and 40 ° C.
- Thermophiles : they have optimal temperatures for their development between 50 ° C and 75 ° C. The only ones that can live above 65 ° C are prokaryotes, that is, they do not have a nucleus.
30 examples of bacteria
- Flavobacterium
- Polaromonas vacuolata
- Chlamydomonas nivalis
- Thermus aquaticus
- Pyrococcus furiosus
- Pyrolobus fumarii
- Thermoproteus
- Thermus aquaticus
- Staphylococcus aureus
- Enterococcus faecalis
- Clostridium botulinum
- Salmonella typhi
- Neisseria gonorrhoeae
- Mycobacterium tuberculosis
- Vibrio cholerae
- Deinococcus radiodurans
- Escherichia coli
- Vibrio fischeri
- Thiobacillus thiooxidans
- Thiobacillus ferrooxidans
- Picrophilus oshimae
- Bacillus alcalophilus
- Natronobacterim gregoryi
- Leptospira interrogans
- Treponema pallidum
- Lactobacillus Casei
- Burkholdeira
- Pseudomonas
- Bacillus Coagulans
- Streptococcus pneumoniae
