Question

How is the viral nucleic acid packaged into a virus particle and distinguished from other nucleic acids in the cell? Explain for segmented and non-segmented viral genomes

Answer 1

Hey there !

Virus are the entities who are capable of replicating themselves, but are really lazy in doing so. That is why they need host's machinery to replicate themselves. Their genes encode for two most important things that help them to stay in host's body, namely-

1. Replicase: Enzyme that replicates the viral genome.

2: Capsid: Protien that protects the viral genome.

Now, most viruses have either RNA or DNA as the genetic material and can be either single stranded or double stranded. The infectious particle of the virus is called VIRION (such a cool bad guy name) and it consists of the nucleic acid (DNA/RNA) and the outer shell of protien.

Now the genome can either be linear, or it can be circular. It can be non-segmented (most often) or it can be segmented, ie,there are many segments of genetic material that complete virus genome. What's cool about this is that, since this microscopic organism is so complex and peculiar, we can easily recognise them by their characteristics.

For example,

1. There is only one single stranded DNA virus- Parvovirus

2. There is only one dsRNA virus- Reovirus

3. Circular viruses are pox and herpesvirus.

Now, Viruses that are RNA often replicate in the cytoplasm, while DNA viruses replicate in the nucleus. A DNA virus don't have an RNA polymerase gene to carry out transcription, therefore it happens in the nucleus by using host RNA polymerase. Whereas, RNA viruses have their own RNA polymerase, so they don't need the nucleus.

Hope this helps!