Bacteria, viruses, and various parasites troubled mankind throughout its history. The examples are not far to seek, outbreak of coronavirus in 2020 — a clear confirmation. But the microorganisms also changed the lives (not always for the worse) and influenced our evolution. For example, parasites have helped our immune system to gain the necessary impetus and become working, and the bacteria is entirely determined rules of life on this planet. It sometimes seems that we humans are just toys in their hands. And here arises a very reasonable question: what, in fact, different germs, bacteria and viruses?
What are germs
Microbes - microscopic organisms that live in the environment. The germs can dwell not only in land, water or air, but even in plants, animals and humans.
Most microbes are harmless to humans, but there are those who, once in the body, cause various diseases and infections. Depending on the structure and effects on humans there are several types of germs, including the most common:
In other words, microbes include the living organisms that surround us. And already they are divided into types. Often in everyday life, a microbes means bacteria, that is, they equate to each other. In theory it is possible to do (we call oranges fruit), but the bacteria is a particular class of microbes.
What is bacteria
Bacteria — single-celled microorganisms (microbes), which is not decorated cell nucleus. This is the most common type of living organisms that inhabit the Earth.
Bacteria are not only “bad” that cause infection and ensuing disease. Many bacteria are an integral part of human life, without them we simply could not life. For example, in this moment, as you read this text, benefit from the work of bacteria. From the oxygen you breath, to nutrients, which remove the stomach of food, you can thank bacteria for the prosperity on this planet. In the body of microorganisms, including bacteria, more than our own cells about ten times.
In the human body about 39 trillion bacteria.
Because of this, many joke that we probably have more germs than humans. And to some extent it really is.
Than bacteria so unique? Everything in the world consists of cells — the building blocks of life, of which are tissues of our body, paw your cat and a tree that grows outside the window. Such cells possess a nucleus and are called eukaryotes. Bacteria do not have nuclei, and their genetic material (DNA) floats freely within the cell. They have other methods of reproduction and transmission of genetic material. Bacteria are considered prokaryotes.
What is the difference between bacteria from germs
To select bacteria among microbes, you must make sure that we are dealing with non-nuclear single-celled organism. That to the experts — microbiologists.
Microbiology is the study of all types of microbes, including bacteria, fungi, viruses and protozoa — helps to distinguish the bacteria from their microbial brethren.
Unlike other microbes, the bacteria produce into categories according to the criteria that apply only to them:
- Survival in an environment without oxygen;
- Form bacteria: Bacillus (bacillus), round (cocci) or spiral (spirillum);
- Whether the bacteria outer protective membrane that prevents staining of the inside of the cell;
- As bacteria move (many bacteria have flagella that allow them to move around).
Most bacteria are beneficial, and they are often used in industry, using a bright as they can is what man can not. Bacteria have evolved to absorb all types of products, from oil spills and by-products of nuclear fission to human waste and decomposition products.
It bacteria cause unpleasant smell that appears in the trash — they recycle food scraps and emitting their own gaseous by-products. You can also blame bacteria that they cause these awkward moments, when you yourself emit gases, or if you breath.
How old is bacteria? Scientists still can’t answer this question. Presumably they have created some of the oldest fossils, which are 3.5 billion years old. How long before that there was the bacteria themselves — and to imagine difficult. The fact that some bacteria can withstand extreme conditions, when either very hot or too cold, or lacking the nutrients and chemicals which we normally associate with life. They can exist almost forever.
Despite having many useful properties, some bacteria can be pathogenic, i.e. cause disease and illness. For example, that bacteria caused the plague: the plague Bacillus Yersinia pestis killed more than 100 million people. It bacteria responsible for staph infection. Moreover, they are characterized by their ability to develop resistance to antibiotics. So the bacteria that cause anthrax, pneumonia, meningitis, cholera, salmonellosis, sore throat and other diseases are always the threat to us.
Most harmful bacteria are able to destroy with antibiotics, but if you stop the treatment early, the bacteria that survive develop resistance to the medication and will remain, waiting for the next chance. Therefore, doctors recommend to complete the course of antibiotics to finish.
Bacteria can also be used as a biological weapon. For example, with their help, at one time artificially staged epidemic of anthrax. So do not underestimate these single-celled organisms. In fact, we are completely at their mercy.
Bacteria of the species Halomonas titanicae right now corrode the metal remaining after the collapse of the ship "Titanic". Imagine what they can do.
What is the virus
But if the bacteria can be so dangerous, why are we more afraid of viruses than bacteria? Unlike bacteria, viruses can infect not only complex organisms, but… the bacteria themselves.
Virus — non-cellular infectious organism that can only live inside living cells.
Viruses can affect all organisms, from animals and plants to bacteria and archaea. At the same time, are parasites, meaning they cannot survive by themselves, unlike bacteria. Viruses use cells (human, plants, animals) to live. If the virus is outside the cell, it exists in the form of viral particles, but can also be dangerous: any contact with a living cell can activate him, give him food. Thus to reproduce the cellular method, the virus can not — its copies it creates only with the help of living cells.
When the virus is near the cell, it attaches to it, creating a link between viral envelope proteins and receptors on the surface of living cells. With this when the virus penetrates inside the cell and releases its genetic material. And there is a case for small — to create copies of itself and to settle in the same way new cells.
What distinguishes bacteria from viruses
The feature of viruses is that they can not change the genetic level. These changes lead to mutations in organisms; in the case of coronavirus, for example, the first virus could infect only animals (bats), and then changed the DNA so that has got ability to infect human cells.
Interestingly, scientists still can't come to the conclusion that it is a live virus or not. So the viruses are called "organisms at the border of the living".
Viruses can be more dangerous than bacteria because of their ability to change at the genetic level. So came the influenza viruses, immunodeficiency, hepatitis A and C. But if the viruses and parasites can’t exist without living organisms, because they like something there? According to one hypothesis, the viruses once (billions of years ago) were small bacteria that parasitize on larger living organisms. Later, these bacteria have been simplified, deprived of functions that are not needed for parasitic lifestyle. Proof of this hypothesis is the existence of Rickettsia and chlamydia. So viruses are “pumped” bacteria that nonetheless are unable to live independently.
The size of the virus particles approximately 100 times smaller than the size of bacteria, and the shape varies from simple helical to more complex structures. One of their forms like a crown. It is the coronavirus.
What is more dangerous bacteria or viruses?
Obviously, viruses can cause much more harmthan the bacteria. For the simple reason that there are no “good” viruses, as in the case of bacteria (like bifidobacteria and lactobacilli, which allow us to digest food). In addition, many viruses are different is just ugly behavior — they can exist within the cells, causing chronic disease. An example of such a virus may be herpes.
All three of the germs, bacteria and viruses, it turns out that the most dangerous are the microbes, since they include all the microorganisms both beneficial and the most harmful to the body. Now scientists are working to extract as many benefits from the “good” bacteria: it is actively exploring the possibility of introducing certain microbes and bacteria in the human body, which can give certain advantages. For example, to destroy the tumor. By the way, because of the bacteria was accidentally discovered penicillin — the antibiotic that has saved many lives.