And one common example of an RNA virus known as the retrovirus that in fact humans is known as HIV or human immunodeficiency virus. Now the next type of category within RNA viruses that we're going to discuss are plus strand RNA and minus strand RNA also known as positive strand RNA and negative strand RNA viruses. Now what exactly is the plus strand or the positive strand RNA virus? So these are the viruses that contain the RNA molecules that serve directly as the mRNA. So once our plus stranded RNA virus inject the RNA into the cytoplasm that same RNA is used to translate into proteins to synthesize those proteins. However, in minus trend RNA viruses the viral RNA that is injected into the cytoplasm must first be transcribed must first be modified into the mRNA before it can actually be used to synthesize our protein.