AP BIOLOGY

Detailed explanation-1: -In higher eukaryotic genomes, Long Interspersed Nuclear Element 1 (LINE-1) retrotransposons represent a large family of repeated genomic elements. They transpose using a reverse transcriptase (RT), which they encode as part of the ORF2p product.

Detailed explanation-2: -Reverse transcriptase first transcribes a complementary strand of DNA to make an RNA:DNA hybrid. Next, reverse transcriptase or RNase H degrades the RNA strand of the hybrid. The single-stranded DNA is then used as a template for synthesizing double-stranded DNA (cDNA).

Detailed explanation-3: -After a retrovirus enters a host cell, reverse transcriptase converts the retroviral RNA genome into double-stranded DNA. This viral DNA then migrates to the nucleus and becomes integrated into the host genome. Viral genes are transcribed and translated.

Detailed explanation-4: -They are approximately 350 base pairs long, do not encode proteins and can be recognized by the restriction enzyme AluI (hence the name). Their distribution may be important in some genetic diseases and cancers. Copy and pasting Alu RNA requires the Alu’s adenine-rich end and the rest of the sequence bound to a signal.