Question

can anyone tell me what is + strand and - strand in Viruses?

Answer 1

RNA viruses that have single-stranded RNA are divided into positive and negative:
Positive (+) RNA virus: their genomic RNA either can serve directly as mRNA (all except the retroviruses) or has the same sequence as the mRNA (so they need no transcription)
Negative (-) RNA virus: they carry an RNA-dependent RNA polymerase that enables the production of the (+) RNA homologue that can be used as a mRNA or as a template to make more negative copies to viral progeny

Conclusion: positive RNA viruses can directly use the RNA genome to produce proteins without being transformed into an intermediate, while negative RNA viruses need to transform their negative RNA into positive before carrying on molecular operations.

Answer 2

Thanks Mate (Y) :)

Answer 3

U're welcome ;)