Question

In the absence of retroviruses, reverse transcription may occur in eukaryotes if which of the following is present?

1) promoters
2) transcription factors
3) retrotransposons
4) prions
5) None of these are correct.

Answer 1

Reverse transcription can occur in eukaryotes in the absence of retroviruses if retrotransposons, which contain the enzyme reverse transcriptase, are present.

Step-by-step explanation:

The direct answer to the question is option 3) retrotransposons. In the absence of retroviruses, reverse transcription in eukaryotes can still occur if retrotransposons are present. Retrotransposons are genetic elements that can amplify themselves in a genome and are capable of the reverse transcription process.

Unlike retroviruses, retrotransposons do not need to infect a cell from the outside; they are already part of the eukaryotic cell's DNA. Since retrotransposons contain sequences that encode the necessary enzyme for reverse transcription, specifically reverse transcriptase, they can synthesize DNA from their RNA sequences within the host cell without the presence of an external virus.