n the Baltimore classification system there are 7 types of virus genome, each of which needs to generate mRNA to express viral proteins. Which of the following genome types produce mRNA in three steps?Choose all that apply     Group of answer choicesdsDNAssDNAdsRNA(+)ssRNA(-) ssRNAssRNA-RTdsDNA-RT

The Baltimore classification system categorizes viruses into seven groups depending on their type of genome and their method of replication. The types that produce mRNA in three steps are:

1. dsDNA (double-stranded DNA)
2. ssRNA(-) (negative-sense single-stranded RNA)
3. dsDNA-RT (double-stranded DNA reverse transcriptase)

Here's why:

1. dsDNA: This type of virus first transcribes the dsDNA into mRNA (step 1), which then undergoes translation to produce viral proteins (step 2). The mRNA is then used as a template to synthesize new dsDNA (step 3).

2. ssRNA(-): This type of virus first uses its negative-sense RNA to synthesize a positive-sense RNA (step 1), which then serves as a template for the production of mRNA (step 2). The mRNA is then translated into viral proteins (step 3).

3. dsDNA-RT: This type of virus first uses its dsDNA to produce mRNA (step 1), which is then translated into viral proteins (step 2). The mRNA is then reverse transcribed back into dsDNA (step 3).