Especially with the COVID-19 pandemic, viruses, whose name we have started to hear frequently, are one of the smallest microorganisms. Viruses, which are discussed whether they are a living thing or not, because they only survive by infecting living cells and multiply in this way, are the biggest enemy of humanity because they cause many different diseases, but they also form the basis of life.
There is no single answer to the question of how viruses reproduce, because there are millions of different types of viruses that have been detected so far, and each of them tends to be transmitted and multiplied in different ways. Likewise, there is not always an easy treatment or preventive vaccine for viral diseases. Let’s take a closer look at how viruses reproduce, how they emerge, and get to know this micro world a little more closely.
First of all, let’s make a definition, what is a virus?
Viruses that infect, spread and multiply by infecting living cells are one of the smallest microorganisms. Viruses, which are also defined as a kind of agent, become hosts in animals, plants or bacteria to maintain their lives. For this very reason, it is a matter of debate whether viruses are alive or not.
Viruses can find a place for themselves in all ecosystems on earth that you do not think of. They are considered the most abundant biological species. Virology, which is the science of viruses; examines viruses that can be found in animals, plants, bacteria, archaea and many more microorganisms.
When we think of a microscopic creature, we think of a virus, but a bacterium is microscopic, and a virus is even smaller than that. Namely, a human cell is about 120 micrometers, e coli bacteria is 1 micrometer, and most viruses are at most 400 nanometers. That’s why we couldn’t see viruses fully until the electron microscope was invented in the 1940s.
Are viruses alive, how did they arise?
Scientists who have studied the evolutionary process over millions of years have been unable to find an origin story for exactly how viruses emerged. It is speculated that some viruses may have evolved from pieces of DNA called plasmids that have the ability to move between cells, while others may have evolved from bacteria.
Viruses are considered an important part of the evolutionary process, as they increase genetic diversity and play a major role in horizontal gene transfer. Whether they are alive or not is a matter of debate. Because they carry genetic material, reproduce and undergo natural selection; that is, they are alive. However, they cannot live without living cells and do not have a cell structure. For this reason, viruses have different definitions such as ‘organisms on the edge of life’ and ‘replicators’.
Viruses were discovered more than a hundred years ago:
After the French microbiologist Charles Chamberland invented a filter in 1884 to see small pores from bacteria, in 1892, Russian biologist Dmitriy Ivanovskiy began to examine organisms infecting tobacco plants with this filter. In the article he published, he talked about the factors that he thought were not bacteria. With the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, humanity became acquainted with viruses.
Since then, virology, a sub-specialty of microbiology, has been working on viruses. To date, it has been discovered that there are millions of different types of viruses. What is interesting is that we can only describe a little more than 6,000 of them in detail. In other words, it is perfectly normal that we meet a new virus every day and do not understand what it is.
Viruses discovered to date generally have two forms, rod and sphere. Viruses that infect bacteria, called bacteriophages, uniquely have a head and a tail. Regardless of shape, all viruses consist of a protein outer shell and have either DNA or RNA genetic material.
So how do these tiny viruses reproduce?
To date, two different methods have been discovered that viruses use to reproduce. These are called the lytic cycle and the lysogenic cycle. Some viruses reproduce using one of these, some using both.
In the lytic cycle, the virus first attaches to the living host cell and then transfers its own DNA to it. Finding the host’s cellular metabolism, DNA begins to build proteins and replicate them. The increasing number of viruses breaks down the cell, gets out and continues the cycle by finding new cells.
In the lysogenic cycle, the virus first attaches to the living cell and transfers its DNA. The DNA of the virus is then incorporated into the DNA of the host cell. Thus, as the host’s cells are replicated, the DNA of the virus is also copied. Eventually the host becomes completely filled with virus DNA.
How do these multiplying viruses spread?
Which one shall we count? For example, viruses in plants are transmitted to insects by using aphids and the plant’s own sap to spread, and then spread to other plants. Viruses found in animals are absorbed by blood-sucking insects and travel across the land. Such carrier insects are called vectors.
Influenza viruses, which we are all familiar with, spread through the respiratory tract. Norovirus and rotavirus, which cause diseases such as gastroenteritis, are transmitted through contact, water and food. Viruses such as HIV that cause AIDS are transmitted sexually or through blood. It can travel on the back of the bacterium, spread between different living things, so a virus can spread in any way it wants.
How are viral diseases treated?
If you say that I will buy a box of antibiotics, you are wrong because antibiotic drugs are used in the treatment of diseases caused by bacterial infections. Eating bonibons has the same effect as taking antibiotics for viral infections. For this reason, viral infections are primarily tried to be prevented through vaccines. Some antiviral drugs can also have a therapeutic effect. Some powerful antiviral drugs prevent the replication of the virus by stopping DNA synthesis.
Viruses will one day be very useful to us:
Damn, don’t think we have to eradicate all viruses, because as we get to know them, we start using them to our advantage. They are of vital importance, especially in gene therapies. We can carry beneficial genes by using viruses that incorporate their DNA into the host DNA. Moreover, we can cause cancerous cells to be destroyed by injecting viruses. It is too early to say for sure, but if we look at the studies, viruses may save our lives in the near future.
Although they cause many diseases in the human body, we tried to open the doors of this micro world a little by answering questions such as how viruses, which form the basis of life, reproduce and how they emerged. It is impossible not to be respected by the scientific world, which works to save our lives with these tiny organisms that are powerful enough to take our lives.
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