Over the centuries, the word "virus" has gradually derived another meaning, referring to any infectious substance.
But it was not until the late19th century that it began to approach our present usage due to an agricultural disaster. (Tobacco mosaic virus, resulting in no harvest in Dutch tobacco farms. )
At first, scientists were completely unsure what it belonged to, even if there was life. Some people even claimed that "humans can't determine the nature of the virus." Until the 20th century, people solved the problem of "what is an enzyme" in biology through X-ray irradiation and crystallization, and some scientists began to think whether the virus is also a kind of protein. (Most of the enzymes are protein, and a few are RNA. ) Then, after several generations of scientists, people finally figured out that the virus is composed of 95% protein and 5% magic long molecules, that is, nucleic acids. Many years later, scientists discovered that ribose is the substance that constitutes genes. (deoxyribonucleic acid, short for DNA; Ribonucleic acid, RNA for short. )
In the 1950s, virologists finally grasped the basic information of the virus. But this is not enough. We still don't know how viruses make people sick.
Viruses are highly variable.
The rhinovirus that can make us catch a cold is ABC III, and we may be infected by these different viruses every year. Once the virus has developed a little resistance, natural selection will also help it develop.
The virus doesn't just hurt me.
In childhood, I was infected with some relatively harmless viruses or bacteria, and some harmless ailments appeared, but in adulthood, the probability of developing allergies and Crohn's disease due to immune system disorder will be reduced.
New viruses can be produced by genetic recombination.
Virus A infects the host 1, and the host helps to copy the gene of virus A and create a new virus A (this is how viruses "reproduce"). At this time, virus B also conquered the host numbered 1 and asked the host to "help" copy the genetic material. This will form a very chaotic scene. Just like animal and plant reproduction, parents' genes are mixed together to produce new DNA. Viruses can also be mixed together to produce viruses with new genes. Of course, the effect of this virus may be more deadly and contagious than before, or it may be milder and less contagious. Just like more human beings, the children of excellent parents are not necessarily as good as them.
Phage, the enemy of the enemy.
As the name implies, viruses that invade bacteria. At first, the scientific community didn't believe this discovery and thought it was ridiculous and incredible. And triggered a bloody battle in the scientific community. Scientists conducted a lot of experiments and found that some experimental bacteria died, but some experimental bacteria did not. Of course, it was later found that there are many kinds of bacteriophages, and the relationship between different bacteriophages and hosts is not the same. Such as "bacteriolytic phage", this state of phage will kill the host in the process of proliferation. There is also a "mild phage", which infects the host and the host will not burst and release new phage; Instead, the genes of these bacteriophages are integrated into the host's own genome, and then the host grows and divides as usual, as if the host and bacteriophage are one.
-To be determined-
People don't know much about viruses. This creature, which has lived on the earth for much longer than us, needs continuous understanding and research from generation to generation.
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I hope to write a review to force me to read carefully and take notes, especially books related to my major. The most important thing is to integrate information and prepare for writing reports and papers. ? ( 'ω' )? (I am moved by myself)