Final answer:
The statement is false; retroviruses like HIV have single-stranded RNA that is reverse transcribed into DNA by reverse transcriptase before the usual transcription into mRNA and translation into viral proteins.
Step-by-step explanation:
The statement that retroviral proteins encode 2 RNA molecules is false. Retroviruses like HIV have genetic material composed of single-stranded RNA (ssRNA), not two RNA molecules. Upon infection of a host cell, retroviruses utilize the enzyme reverse transcriptase to convert their ssRNA into DNA, an intermediary step that differs from the general pathway of gene expression where DNA is normally transcribed into mRNA.
After the viral RNA is reverse transcribed into DNA, it is integrated into the host's genome and subsequently transcribed into mRNA, which is then translated into viral proteins. This process is a key part of the retrovirus life cycle and is an example of the exceptions to the central dogma of molecular biology.