Question

Double-stranded DNA (dsDNA) copy of the viral RNA genome integrates into a host chromosome to form a ___________.

Answer 1

The double-stranded DNA copy of a viral RNA genome that integrates into a host chromosome is known as a provirus. This process is facilitated by the enzyme reverse transcriptase, characteristic of retroviruses like HIV, enabling chronic infection.

Step-by-step explanation:

The double-stranded DNA (dsDNA) copy of the viral RNA genome that integrates into a host chromosome forms a provirus. This integration is a characteristic feature of Group VI viruses, which are also known as retroviruses. They possess diploid ssRNA genomes, and using the enzyme reverse transcriptase, they synthesize a complementary dsDNA from their RNA genome. This dsDNA is then transported into the nucleus of the host cell where it integrates into the host's own DNA.

Once the viral DNA is inserted, it resides in the host chromosome and can direct the synthesis of viral mRNA through the process of transcription, thus enabling the production of viral proteins and new viruses. This integration facilitates a chronic infection as the provirus can remain with the host for a prolonged duration. The mechanism of integration is analogous to the prophage stage in bacteria but with the key difference that, unlike prophage, the provirus typically does not excise itself from the genome.

Answer 2

A double-stranded DNA (dsDNA) copy of the viral RNA genome integrates into a host chromosome and is called a provirus. This is a characteristic process of Group VI viruses, such as HIV, which use reverse transcriptase to form the dsDNA that integrates into the host genome.

Step-by-step explanation:

The double-stranded DNA (dsDNA) copy of the viral RNA genome that integrates into a host chromosome to form a stable genetic element is called a provirus.

This process is characteristic of Group VI viruses, also known as retroviruses, which include HIV. These viruses contain diploid ssRNA genomes and use the enzyme reverse transcriptase to convert their RNA into complementary DNA (cDNA).

The cDNA is then converted into dsDNA and integrated into the host's genome, where it can remain for a long period and establish a chronic infection. The integrated dsDNA can be transcribed to produce mRNA for the creation of viral proteins.