Define A virus in 500 words?
Answers
Explanation:
virus is the smallest type of parasite to exist, usually ranging from 0.02 to 0.3μm in size, although some viruses can be as large as 1μm.
A viral particle or virion contains a single nucleic acid (RNA or DNA) core surrounded by a protein coat and sometimes enzymes that are required to initiate viral replication. Viruses can only replicate within the cells of animals, plants, and bacteria and, as such, are referred to as obligate intracellular parasites.
Viruses are not classified according to the illnesses they cause; instead, they are grouped into different families based on whether the nucleic acid is single- or double-stranded, whether a viral envelope is present and their mode of replication.
Rabies is a deadly viral disease of the nervous system, 3d illustration Credit: nobeastsofierce / Shutterstock
Rabies is a deadly viral disease of the nervous system, 3d illustration Credit: nobeastsofierce / Shutterstock
Single-stranded RNA viruses are further classified based on whether they have positive- or negative-sensee RNA. DNA viruses tend to replicate within the nucleus of host cells, whereas RNA viruses generally do so in the cytoplasm.
Historically, few parasites have caused the devastation of animals, plants, and humans that viruses have. Diseases such as polio, foot, and mouth and smallpox are all well known for the widespread, devastating effect on people and animals. Less well known about is the complete crop failure that a vast number of viruses have the potential to cause.
Are viruses alive?
When researchers first discovered viruses and realized they seemed to behave similarly to bacteria, they generally became considered as biologically "alive."
Ad
However, this changed in the 1930s when it was demonstrated that virions lacked the mechanisms that are required for metabolic function. Once scientists determined that viruses simply consist of DNA or RNA contained within a protein shell, they generally became thought of as biochemical mechanisms rather
Answer:
hey hii good afternoon dear have a nice day my love ❤❤❤❤❤❤
Explanation:
The earliest indications of the biological nature of viruses came from studies in 1892 by the Russian scientist Dmitry I. Ivanovsky and in 1898 by the Dutch scientist Martinus W. Beijerinck. Beijerinck first surmised that the virus under study was a new kind of infectious agent, which he designated contagium vivum fluidum, meaning that it was a live, reproducing organism that differed from other organisms. Both of these investigators found that a disease of tobacco plants could be transmitted by an agent, later called tobacco mosaic virus, passing through a minute filter that would not allow the passage of bacteria. This virus and those subsequently isolated would not grow on an artificial medium and were not visible under the light microscope. In independent studies in 1915 by the British investigator Frederick W. Twort and in 1917 by the French Canadian scientist Félix H. d’Hérelle, lesions in cultures of bacteria were discovered and attributed to an agent called bacteriophage (“eater of bacteria”), now known to be viruses that specifically infect bacteria.