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RNA Viruses
RNA viruses are biological. viruses chemically associated with or based on the RNA molecule. Mostly, viruses tend to be of the RNA virus category, as this is the simplest, most facilitative method of continued existence for the virus itself.
RNA viruses tend to affect plants predominantly, as they (the viruses) are a simpler genetic structure, and therefor are likely to infect a simpler genetic life form such as plant life.
The replication centre of an RNA virus is the cellular cytoplasm, rather than the nucleus itself, as is the case in DNA viruses.
RNA viruses fall under four main categories. These are as follows: i)
(+)ssRNA viruses, ii) (-)ssRNA viruses iii) dsRNA viruses and iv) dsRNA-RT viruses as
illustrated and briefly exemplified below.
1) (+)ssRNA viruses: The 'ss' in this case, stands for Single-Strand,
referring to the fact that the virus in question maintains only one
polymer strand of RNA. Chemically, this means that the polymer strand
of the virus in question is not attached to a parallel partner strand,
drastically changing the behavioural replication and chemical
interaction patterns of the virus itself. +ssRNA is referred to as such, because it is chemically identical to mRNA, an important and key factor in the genetic replication process of the virus. Since +ssRNA is identical to mRNA, it can replicate immediately by translations through the host cell.
2) (-)ssRNA viruses: Similar to +ssRNA, the -ssRNA is only different from the (+) version in the sense that it is chemically complimentary (rather than identical) to the mRNA molecule. As such, it requires additional stages during the replication process through the host molecule, thus further complicating the genetic replication of the virus.
3) dsRNA viruses: the 'ds', in this case, stands (obviously) for
Double-Strand, evidently referring to the fact that the virus contains
a dual stranded polymer chain, whereby each base element connected to
the polymer chain is in fact paired with another base element connected
to a parallel polymer chain.
4) dsRNA-RT refers to the fact that the viral molecule in question is
not only Double Stranded, but also 'Reverse Transcribing' as well. This
points to the fact the the replicative process of the RNA strand of the
virus is in fact physio-chemically 'backwards' from the traditional
replicating method. Reverse transcribing viruses are, of course, less
common than standard replicating viruses, but still just as deadly to
another living organism in the traditional 'viral' sense.
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