Question

Which of the following enzymes are commonly found within viral capsids???

A.)		DNA-dependent RNA polymerase
B.)		RNA-dependent RNA polymerase
C.)		Reverse Transcriptase
D.)		Telomerase
E.)		a, b and c

Answer 1

Viruses can be categorized into main three categories according to the nature of viral genome:

1. DNA virus

2. RNA virus

3. Reverse transcribing viruses

A virus needs to covert the genomic information into messenger RNA (mRNA) and translates it into viral proteins. Moreover, it also needs to replicate identical copies of its genome to encapsulate in the newly assembled viral capsid.

Therefore, according to the nature of the genomic material different virus-encoded polymerases are required

DNA virus replicates their genome by means of DNA-dependent DNA polymerases and transcribes mRNA using DNA dependent RNA polymerases.

RNA virus replicates and transcribe their genome using RNA dependent RNA polymerases

The reverse-transcribing virus can have either RNA or DNA as genomic material. Retrovirus have single-stranded RNA (ssRNA) that replicate via DNA intermediate which requires RNA dependent DNA polymerases also known as reverse transcriptase

Telomerase also known as terminal transferase is an enzyme which posses a specialized reverse transcriptase activity used in the elongation of telomeric region of eukaryotic chromosome not common in the virus.

Therefore option E is the correct choice