Introduction: Since 2019, the new crown epidemic began to spread, and now it can be said that it has become a normalization. The culprit of this outbreak is undoubtedly the “coronavirus”. What is overwhelming is the constant mutation of this virus, which has led to the fact that the antibodies studied in humans cannot be fully immune for the time being.
There are a variety of organisms on our earth, and viruses are one of them. At the same time, because of the existence of the virus, it poses a certain threat to the life and health of other life forms on the earth.
1. Definition of virus and structure of virus
We all know that almost all of us humans and the vast majority of organisms are dual-core inheritance, using DNA as genetic information. But the virus is different. It is only composed of a nucleic acid molecule, that is, it only has deoxyribonucleotides (DNA) or only ribonucleotides (RNA), and then binds to the form formed by proteins (non-cellular) . Its size is very small, much smaller than bacteria.
Viruses also have a relatively diverse structure, such as decahedron, spiral, etc. The structure of a virus is a protein coat that surrounds the nucleotides that represent its genetic information. The survival and reproduction of viruses mainly rely on parasitism in other cell species. Therefore, whether a virus is a living organism or not, the scientific community’s definition of it is relatively vague.
At the same time, viruses are not classified into the five categories of protists, prokaryotes, fungi, animals and plants. The reproduction mode of the virus is completed in its host cell, using the proteins in the host cell and the continuous replication of its own genetic information.
Viruses cannot grow and reproduce independently of host cells. Its infectious ability is extremely strong, and it can infect almost all organisms with cellular structures. However, some people ask what is the origin of the specific virus? Now the scientific community is also scratching their heads (currently, it is relatively accepted that viruses originated from plasmids and bacteria).
2. Virus reproduction mechanism and process
We briefly mentioned above that virus reproduction, in fact, virus replication refers to a process in which viruses invade host cells and then release genetic information. The whole process includes virus adsorption, genetic information entry, gene expression, and genetic information. replication, binding to proteins, and release of large amounts of virus. There may be slight differences depending on the type of virus.
1. Adsorption and entry of viruses
Taking T4 phage as an example, the virus first binds to the receptor on the surface of E. coli, and then penetrates the membrane structure of E. coli through the tail shaft, and transfers the genetic information (DNA or RNA) inside the protein to the inside of E. coli.
2. Expression of viral genes
After the genetic information of the virus enters E. coli, the genetic information is translated in E. coli by means of transcription to form a large number of corresponding proteins (including enzyme substances and protein structures). This series of processes is also known as gene expression.
3. Virus transcription
Virus transcription is mainly carried out in six ways. The way of transcription is almost the same as that of host cells. It needs to transcribe messenger RNA through the process of double-strand formation, and then translate it to form a new genetic information. There are different ways of transcription according to different viral nucleic acid types.
3. Why do viruses mutate so frequently and what drives them to mutate
I believe everyone must have heard the word “gene mutation”. Gene mutation occurs in all organisms, and human beings will also have gene mutation. At the same time, it is precisely because of gene mutation that the evolution and development of organisms are caused. Similarly, the mutation of the virus is also due to the existence of genetic mutation.
That’s why virus mutations can be so frequent, while other species’ mutations are rare. First of all, the genetic information of human organisms is determined by DNA, and DNA has a double-helix structure. This structure is very stable, and some purines are not prone to mutation, etc., which also leads to DNA double-stranded structure of biological genes Mutations are rare.
The virus is different. Its genetic information includes DNA and RNA. However, they are all single-stranded structures. Relatively speaking, they are extremely unstable and easy to mutate, even caused by purine pairing errors. Therefore, virus mutation will be more frequent.
Write at the end. To sum up, the variability of the virus is determined by its special structure and growth and reproduction. For example, our current new crown virus has mutated nearly 240 viruses such as “Omicron virus” and “beta virus”.
It can be seen that, in view of the current anxious situation of the global epidemic, it is necessary to prevent not only the existing strains, but also the harm caused by the strains that may be mutated. Therefore, readers and friends, if you are interested in the new coronavirus, you can do more research on the mutation mechanism and reproduction mechanism of the virus.