kkentm Posted June 20, 2011 Report Share Posted June 20, 2011 Just wondering why RNA containing viruses have to synthesize DNA and then insert it into the host cell's nucleus instead of having their RNA translated by ribosomes in the cytoplasm right away? Im sure theres a very simple answer for this but I just need to know... Thanks Link to comment Share on other sites More sharing options...
thehumanmacbook Posted June 20, 2011 Report Share Posted June 20, 2011 Just wondering why RNA containing viruses have to synthesize DNA and then insert it into the host cell's nucleus instead of having their RNA translated by ribosomes in the cytoplasm right away? Im sure theres a very simple answer for this but I just need to know... Thanks I think you mean why the lysogenic cycle exists - and some believe that is to prolong the viruses' occupation of the host organism. However, no one is really sure why some viruses do that: http://en.wikipedia.org/wiki/Lysogenic_cycle If it were translated almost immediately, that would be the lytic cycle: http://en.wikipedia.org/wiki/Lytic_cycle -> quicker destruction of target cell Link to comment Share on other sites More sharing options...
kkentm Posted June 20, 2011 Author Report Share Posted June 20, 2011 well my kaplan book makes 2 distinctions between RNA containing viruses: those that use reverse transcriptase ie retroviruses and those that use RNA replicase however, im still wondering why it is necessary for viruses to replicate their RNA or synthesize DNA when they already have strands of RNA. why cant their original RNA strands be translated by the ribosomes of the host cell? Link to comment Share on other sites More sharing options...
kkentm Posted June 20, 2011 Author Report Share Posted June 20, 2011 now that i think about it, maybe RNA replication is necessary so that the virus atleast retains some sort of genetic information? is that correct? cuz if its original RNA was used for translation then the virus would be completely absent of genetic information (temporarily) until translation was complete Link to comment Share on other sites More sharing options...
thehumanmacbook Posted June 20, 2011 Report Share Posted June 20, 2011 They can - plus strand viruses can immediately be translated by harnassing the cell's ribosomes. Ex. influenza virus. However, some viruses are minus stranded DNA, or even double stranded RNA - and some are even single/double stranded DNA viruses. You can't simply cram that into a ribosome and demand protein translation... So by nature's design...there's no clear answer, I think it depends on the type of virus and it's construction. Link to comment Share on other sites More sharing options...
kkentm Posted June 20, 2011 Author Report Share Posted June 20, 2011 They can - plus strand viruses can immediately be translated by harnassing the cell's ribosomes. Ex. influenza virus. However, some viruses are minus stranded DNA, or even double stranded RNA - and some are even single/double stranded DNA viruses. You can't simply cram that into a ribosome and demand protein translation... So by nature's design...there's no clear answer, I think it depends on the type of virus and it's construction. k thanks. thats wat i was wondering since my book didnt mention any viruses that can translate their RNA without replication involved. Link to comment Share on other sites More sharing options...
thehumanmacbook Posted June 20, 2011 Report Share Posted June 20, 2011 now that i think about it, maybe RNA replication is necessary so that the virus atleast retains some sort of genetic information? is that correct? cuz if its original RNA was used for translation then the virus would be completely absent of genetic information (temporarily) until translation was complete That wouldn't matter - the initial infecting virus is never really "put back together"; it can't re-engineer a new capsid and such for the strand. Either it enters the lytic or lysogenic cycle to produce virions, so I don't think that this conservatism of the initiating virus exists. I may be wrong though, it doesn't make too much sense to me (ex. how could the provirus suddenly peel itself off of the DNA strand in the lysogenic cycle to be re-transcribed into a virion? Somewhat inefficient, wouldn't you say?) Link to comment Share on other sites More sharing options...
TheBoss Posted June 20, 2011 Report Share Posted June 20, 2011 They can - plus strand viruses can immediately be translated by harnassing the cell's ribosomes. Ex. influenza virus. However, some viruses are minus stranded DNA, or even double stranded RNA - and some are even single/double stranded DNA viruses. You can't simply cram that into a ribosome and demand protein translation... So by nature's design...there's no clear answer, I think it depends on the type of virus and it's construction. This post pretty well answers the main question. If you want to know more about the different types of viruses, you could look up the Baltimore classification system, although you obviously wouldn't have to know it. Link to comment Share on other sites More sharing options...
thehumanmacbook Posted June 20, 2011 Report Share Posted June 20, 2011 This post pretty well answers the main question. If you want to know more about the different types of viruses, you could look up the Baltimore classification system, although you obviously wouldn't have to know it. LIKE A BOSS. And yeah, baltimore classification is pretty cool. http://en.wikipedia.org/wiki/Baltimore_classification But I think all you need to know are + strand, minus strand, retroviruses, and some other forms exist. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.