Which of the following would be the first step in the biosynthesis of a virus with reverse transcriptase?
a. A complementary strand of RNA must be synthesized.
b. Double-stranded RNA must be synthesized.
c. A complementary strand of DNA must be synthesized from an RNA template.
d. A complementary strand of DNA must be synthesized from a DNA template.
e. None of the above

Verified step by step guidance

1. Understand that viruses with reverse transcriptase, such as retroviruses, have an RNA genome that needs to be converted into DNA inside the host cell.
2. Recall that reverse transcriptase is an enzyme that synthesizes DNA from an RNA template, which is the reverse of the usual transcription process.
3. Identify that the first step in the biosynthesis of such a virus involves creating a complementary DNA strand from the viral RNA genome.
4. Recognize that this step is crucial because the newly synthesized DNA can then integrate into the host genome for further replication and transcription.
5. Conclude that the correct first step is the synthesis of a complementary DNA strand from an RNA template, corresponding to option c.

Key Concepts

Reverse Transcriptase Function

Reverse transcriptase is an enzyme used by certain viruses, like retroviruses, to synthesize DNA from an RNA template. This process is the reverse of the usual transcription, allowing the viral RNA genome to be converted into DNA for integration into the host genome.

Viral Genome Replication in Retroviruses

Retroviruses carry RNA genomes that must be reverse transcribed into DNA before replication. The first step in their biosynthesis involves creating a complementary DNA strand from the viral RNA, which then forms double-stranded DNA for integration.

Central Dogma of Molecular Biology and Its Exceptions

The central dogma states that genetic information flows from DNA to RNA to protein. Reverse transcriptase viruses are exceptions, as they convert RNA back into DNA, highlighting the unique replication strategy of retroviruses.