Viruses, Prions, And Viroids

What are Viruses, Prions, And Viroids?

What are Viruses, Prions, and Viroids? They sound like some kind of robots from Star Trek, don't they? We'll they may not be from Star Trek but they are foreign to other organisms, and they are definitively something you do not want to come into contact with! 

Viruses are and infective agent that have nucleic acid molecules in a protein coat. They are widely considered nonliving but also have traits of being living by the particular state that they are in. They cannot survive with out a host cell and depend on protein syntheses of living cells to reproduce. They are about ten times smaller then average bacteria making them too small to be seen by a light microscope. Once they enter a cell in as little as ten minutes, a virus may take over a cell, copy itself hundreds of times, and kill the cell. There are many forms of viruses and they can do remarkably terrible things. The most common form of a virus is the Influenza virus, or even more commonly known; the flu. It can be spread as all viruses through the air, by being swallowed, or inhaled, and also through skin to skin touch. It can cause a dry cough, sneezing, high temperature, aches and pains throughout the body, and extreme sleepiness.  The way to treat a virus is by resting, eating healthy, and drinking plenty of fluids since they cannot be treated with antibiotics.

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Prions are a protein particle that is believed to be the cause of brain disease. They do not contain nucleic acid such as viruses but are believed to be responsible for a family of illnesses called Transmissible Spongiform Encephalopathies (TSEs), these include but are not limited to including Scrapie in sheep, Kuru in humans, and "mad cow disease" in cows. These diseases are all caused by the beak down of the nervous system and once an autopsy of the brain has been done of a specimen it has shown that the tissue has been literally eaten away forming holes in it. TSE diseases cannot be treated. Organisms can become infected with TSE prions by ingesting them in things like infected tissue in meats and through contaminated blood products, animals come upon them by eating contaminated feed from which they used animal byproducts that were contaminated.    

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Viroids are a small RNA that infect plants. They are 80 times smaller than a typical virus and consisting only of a nucleic acid without a protein coat. In order to protect themselves since they do not have a protein coat they mask themselves appear to be items from the host organism's cell. In order to reproduce they take control of polymerase 2, an enzyme that combine messenger RNA within the cell, and uses that to produce copies of itself. The after effects of viroids is after however long its takes for them to gain control of the plant, ranging from two weeks in tomato plants to two years in potato plants with the Potato spindle tuber viroid, the plants growth is stunted. Although it started out as an issue among plants, scientist are now trying to apply it to items in agriculture, an example of this is them trying to make smaller or 'dwarf' citrus trees. 

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