Microbiology Practice Exam

A retrovirus is a specific type of RNA virus that has the unique ability to integrate its genetic material into the host genome. This process typically involves reverse transcription, where the viral RNA is reverse-transcribed into DNA by the enzyme reverse transcriptase. Once the viral DNA is formed, it can be integrated into the host's chromosomal DNA via integrase, allowing the virus to persist in the host cell, potentially leading to replication during cell division.

This integration is a hallmark of retroviruses and is instrumental in their lifecycle and pathogenicity. They can cause long-lasting infections because the integrated viral genome can be transcribed and translated by the host's cellular machinery, leading to the production of new virions. This ability to insert genetic material into the host's genome distinguishes retroviruses from other types of viruses that may rely solely on their RNA or DNA to produce new viral particles without integrating into the host genome.

In contrast, other virus types mentioned in the options do not typically integrate into the host genome in this manner. Traditional RNA viruses generally remain in the cytoplasm and do not integrate their genetic material, while most DNA viruses can replicate within the nucleus but do not necessarily integrate into the host's DNA. Envelope viruses refer to a classification based on