Can ribosomes also manufacture nucleic acid & not just protein, like when a virus reproduces itself inside a host cell?

Question

As I understand it, ribosomes in the cell manufacture proteins as needed by the body, but only proteins & not nucleic acids. Yet when a virus invades & hijacks the machinery of the host cell for its own purposes, the final product is thousands of newly minted copies of the whole virus nucleoprotein--that is, protein & nucleic acid together. How did the nucleic acid part come about--was it also produced by the host cell’s ribosomes,or by some other mechanism in the cell?

Anonymous · Answer

Per Wikipedia’s "Virus" there are 6 BASIC STAGES in viral replication: attachment (to the surface of the host cell it invades), penetration, uncoating, replication, assembly, release

The REPLICATION STAGE "involves primarily multiplication of the genome"; and viral protein synthesis is followed by "viral genome replication". From these it is clear that indeed the end product is not just protein material but genetic, or nucleic acid, material.

We should distinguish between 2 types of viruses: DNA virus & RNA virus.

If DNA type, genome replication usually takes place in the host cell’s nucleus; if RNA type, in that cell’s cytoplasm—where of course the ribosomes are located.

Incidentally, the COVID virus (SARS-CoV-2) is the RNA type. And "all RNA viruses use their own RNA replicase enzymes to create copies of their genes"

From the foregoing, I think it's safe to conclude the host cell’s ribosomes do manufacture nucleic acids as well as proteins when invaded by a virus. Whereas  in normal conditions they'd produce only protein material, since there is no need to replicate their own genome (which  theyre able to do as a matter of course in the process of cell division)

What's more, what could be more intriguing is that it appears the host cell could produce the viral copies—nucleic acid, protein & all—without even using ribosomes! This in the case of DNA virus. For while there are millions of ribosomes in the host cell’s cytoplasm, so far as is known none are present in its nucleus nor in the protoplasm that houses it

Cowboy · Answer

DNA codes for both proteins and RNA.....

? · Answer

Why do you have to pose this question more than once?

hcbiochem · Answer

The viral proteins are synthesized by the host cell ribosomes which translate viral mRNA molecules. The viral nucleic acid is produced by replication (of DNA viruses) or by multiple rounds of transcription for RNA polymerases. Find a microbiology text and read the introductory chapter on viruses.

So, no, ribosomes cannot synthesize nucleic acids.

Can ribosomes also manufacture nucleic acid & not just protein, like when a virus reproduces itself inside a host cell?

4 Answers