Question

Which is FALSE in regard to retroviruses and some retrotransposons?

a) 4 bp from each of the two most external ITRs are lost during ds DNA insertion into the host genome.
b) ITRs are a part of LTRs.
c) LTRs represent direct repeats at the retrovirus DNA form of genome.
d) The RNA form of retrovirus has incomplete LTRs.

Answer 1

The claim that 'The RNA form of retrovirus has incomplete LTRs' is false; retroviruses have complete LTRs in their RNA form. Unlike retroviruses, LTR retrotransposons lack the ability to form infectious particles and do not have an ENV gene-encoded envelope. Non-LTR retrotransposons like LINEs do not possess LTRs at all.

Step-by-step explanation:

The student asked which statement is FALSE regarding retroviruses and some retrotransposons. The correct answer is that the statement 'The RNA form of retrovirus has incomplete LTRs' is FALSE. Retroviruses, unlike retrotransposons, do indeed have complete Long Terminal Repeats (LTRs) in their RNA form. Although LTR retrotransposons share many features with retroviruses, such as reverse transcriptase, integrase, and LTRs for replication and integration into the host genome, they lack the infectious properties of retroviruses and do not contain the ENV gene-encoded envelope.

An important distinction to note is that non-LTR retrotransposons, like LINEs, do not have LTRs but rather encode the enzymatic machinery needed for their transposition and generate direct repeats flanking the inserted element. It is only the LTR retrotransposons that possess LTRs and are more structurally similar to retroviruses.