Are bacteria living things?

Despite being invisible to the human eye and having different structures and functions than eukaryotic cells and multicellular organisms, science DOES recognize bacteria as living beings . In fact, they are one of the most primitive groups of living beings, that is, they appeared at the beginning of the beginning of life on Earth.

What are bacteria – definition

Bacteria are unicellular microorganisms , made up of a single cell of the prokaryotic type (from the Greek “pro”, primitive and “karyotic”, nucleus). The vast majority of bacteria are free-living, except those that are obligate intracellular. However, all of them have mechanisms that produce energy and genetic material, both necessary for their growth and development.

In the next section we will see more characteristics of these amazing microorganisms to learn how to differentiate them from other types of microorganisms and living beings. In addition, we recommend that you read this other AgroCorrn article about the Difference between viruses and bacteria .

As we have seen in the previous section, bacteria are prokaryotic unicellular microorganisms , but what other characteristics of bacteria can we observe?

• In their cellular structure they lack intracellular compartments delimited by membranes, and their DNA is always circular and closed.
• They have a strong cell wall that allows them to survive in extreme environmental conditions. In this wall appear fimbriae, pilis or flagella, which bacteria use to communicate with each other, as well as to perceive chemical information from their environment, or even to move inside aqueous environments.
• The reproduction of bacteria is always asexual, and it is carried out by a simple division method known as binary fission (as opposed to the mitosis division process used by eukaryotic cells). Thus, during binary fission, the cell that constitutes the bacterium grows and forms an intracellular protein septum, which will allow the formation of two daughter cells, which contain an identical duplicate of the stem cell’s genome.
• Most bacteria multiply rapidly, forming colonies of bacteria in a few hours, provided they have a temperature and atmosphere that favors their development.

The variety of families of bacteria that exist in nature is really extensive and varied. In the next section we will see what types of bacteria exist and how we can group them.

By observing bacteria with different chemical colorations under the light microscope, it is possible to identify their structures and shapes. In this way, it is possible to classify the types of bacteria as follows:

• Spirils (spiral).
• Cocci (spherical or oval).
• Bacilli (cylindrical or rod-shaped; straight or curved).

On the other hand, it is possible to differentiate two large groups of bacteria according to the environment in which they live and the absence / presence of peptidoglycan in their cell walls:

• Archaeobacteria: They lack peptidoglycan and live in anaerobic and acidic environments with high temperatures, such as the deep sea.
• Eubacteria: They have peptidoglycan in their cell wall. They live freely in multiple environments such as soil and water; but also inside living organisms. This group includes bacteria of medical interest, photosynthetic green and purple bacteria, as well as cyanobacteria.

To get a closer look at some of the most abundant and well-known bacteria, let’s look at some of the names of the bacteria and the diseases they cause :

• Botulismo: Clostridium botulinum
• Difteria: Corynebacterium diphtheriae
• Cholera: Vibrio cholerae
• Gastritis: Helicobacter pylori
• Gonorrea: Neisseria gonorrhoeae
• Leprosy, Mycobacterium leprae
• Meningitis: Neisseria meningitidis
• Pneumonia: Staphylococcus aureus
• Fish: Yersinia pestis
• Salmonella: Escherichia coli
• Tétanos: Clostridium tetani
• Tos ferina: Bordetella pertussis
• Tuberculosis: Mycobacterium tuberculosis

Despite all the disease-causing bacteria that we have seen in the previous section, there are also a large number of species of bacteria that create symbiosis and positive relationships with living beings. Learn more about What is symbiosis in ecology and biology with examples here.

Therefore, we can affirm that bacteria are living beings and good and bad microorganisms , depending on the species of bacteria and its relationship with one or another living organism. Thus, within the beneficial symbiotic relationships in which some bacteria participate, we can highlight:

• The bacterial flora present in the digestive system of humans and other animals such as ruminants.
• Nodulating nitrogen-fixing bacteria that live in the root nodules of legume plants.
• Bacteria from probiotics frequently used as supplements in the diet.
• Bacteria that live in association with algae for the decontamination of waters and in the decomposition of bioplastics.

If you want to learn more about bacteria, you can also read this other article about the Monera Kingdom: what it is, characteristics, classification and examples , because bacteria and other living beings belong to this kingdom of nature.

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