Which organism is not a DNA virus?

Which organism is not a DNA virus?

• A. Hepatitis B
• B. Adenovirus
• C. Influenza
• D. CMV

Answer: (C)

The key idea here is distinguishing viruses by the type of genome they carry: DNA or RNA. Influenza has an RNA genome (negative-sense, single-stranded RNA, segmented) and does all transcription and replication with an RNA-dependent RNA polymerase brought in by the virus; there is no DNA stage in its life cycle. The other organisms listed—Hepatitis B, Adenovirus, and CMV—have DNA genomes (Hepatitis B is a DNA virus that uses reverse transcription during replication, while Adenovirus and CMV are double-stranded DNA viruses). So the one that is not a DNA virus is the influenza organism.

The key idea here is distinguishing viruses by the type of genome they carry: DNA or RNA. Influenza has an RNA genome (negative-sense, single-stranded RNA, segmented) and does all transcription and replication with an RNA-dependent RNA polymerase brought in by the virus; there is no DNA stage in its life cycle. The other organisms listed—Hepatitis B, Adenovirus, and CMV—have DNA genomes (Hepatitis B is a DNA virus that uses reverse transcription during replication, while Adenovirus and CMV are double-stranded DNA viruses). So the one that is not a DNA virus is the influenza organism.