Non-Living Entities that Functioning as Organisms (L40)

There are many questions to be asked when studying biology; what is that? what does it do? why does it do it? Is it alive? Despite the fact that biology itself is “the study of living organisms, divided into many specialized fields that cover their morphology, physiology, anatomy, behavior, origin, and distribution”, there are a few instances where work is being carried out by things that aren’t quite alive, however they do act as though they are. Examples of such entities include viroids, retrovirsues, and prions.
Viroids are short strands of RNA that have been given the mission of inserting themselves into (plant) cells, and self-replicating using the host cell’s enzymes to do so. This can interfere with natural plant cycles and result in stunted growth.
Retroviruses are class IV animal viruses, and can be extremely serious; these particular viruses consist of a single-stranded RNA that serve as a template for DNA. The process of a retrovirus begins by the entering of a cell; reverse trancriptase then creates DNA from the RNA template. The new viral DNA (provirus) is then incorporated into the cell genome. The cell goes on to produce more RNA genome, reverse transcriptase and other viral proteins. Eventually  these are assembled to create a new virus which leaves the cell and spreads to others. Viruses are made up of protein and nucleic acids; RNA (specified nucleic acid) enables a virus to reprogram a cell to create more viruses and replicate the viral genome. One example of a retrovirus today is HIV.
Lastly, prions are proteins that multiply (self-replicate) by infecting other proteins. (This is an exception to Crick’s Central Dogma theory). These proteins have been misfolded, and in turn cause other proteins to misfold around it. Unfortunately, these misfolded proteins are extremely stable, and there is no known cure or treatment to the issue as of current. Prions are known to be the cause of many serious illnesses, one of which being Mad Cow disease.

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