According to K. Weze, all living beings are divided into several domains. There are three of them: bacteria, archaea and eukaryotes. Viruses are considered as a non-ranking category. The fact is that not all scientists attribute this group of creatures to the living world. But the majority, like the creator of the RNA world hypothesis, tends to group viruses into a separate domain. And this, despite the fact that bacteria and viruses are the smallest among other creatures, and are also quite simply arranged.
The question of the origin of viruses and bacteria remains open. There is not even an exact idea which of these groups appeared earlier. It is logical to assume that viruses and bacteria should have a common ancestor and at least the same origin. The first theories were based on such judgments. But a detailed study of these microorganisms led to the conclusion that the differences between viruses and bacteria are more significant than previously thought.
The difference between viruses and bacteria
The most important of these differences is the way of life that bacteria and viruses have completely different. The first, despite the simplicity of their device, are beingsindependent. Even if they live inside a cell. As do, for example, chlamydia. Viruses outside the cell have no biological activity. They generally lack any organs for elemental metabolism. A particle of all viruses consists of two elements. This is the genome (it is represented by one or two strands of ribonucleic acid) and a protein shell. Some have an additional capsid on top of the shell.
All viruses, depending on what kind of ribonucleic acid they have, are divided into two large groups: RNA- and DNA-containing.
The shape of viruses can be of several variants.
- Icosahedrons.
- Phages.
- Octahedrons.
- Spiral.
Bacteria and viruses are quite different in size. If the sizes of the former are measured in units and hundreds of micrometers, then the largest virus is no more than 1300-1400 nanometers. Thus, the largest virus is smaller than the smallest bacterium.
The pathogenicity of viruses depends on their ability to penetrate certain cells.
While the existence of bacteria requires a combination of protection from the aggression of the macroorganism and the ability to rapidly increase in numbers and form colonies. In other words: it is most important for bacteria to "conquer" a certain living space in which to exist.
Accordingly, both bacteria and viruses have different sensitivity to drugs aimed at their destruction. As an antiviral drug, the mostInterferons and their analogues are effective. To fight bacteria, antibiotics are used, which do not work on viruses.
The entire life cycle of viruses can be described in several stages. First, the particle enters the cell. The virus genome is then integrated into the cell genome. The latter begins to produce copies of the virus, and the cell's organelles switch from their own metabolism to creating shells for these genomes. Then the virus particles exit the cell and everything starts again.
Viruses pathogenic to humans cause measles, smallpox, rubella, polio, AIDS, colds of the upper respiratory tract and others. Whereas bacteria are the culprits of whooping cough, diphtheria, typhoid, etc.
