Ciro Santilli @cirosantilli 37

Converts RNA to DNA, i.e. the inverse of transcription. Found in viruses such as Retrovirus, which includes e.g. HIV.

Makes RNA from RNA.

Used in Positive-strand RNA virus to replicate.

I don't think it's present outside viruses. Well regulated organisms just transcribe more DNA instead.

Converts DNA to RNA.

Sequencing the DNA tells us what the organism can do. Sequencing the RNA tells us what the organism is actually doing at a given point in time. The problem is not killing the cell while doing that. Is it possible to just take a chunk of the cell to sequence without killing it maybe?

Sequence alignment is trying to match a DNA or amino acid sequence, even though the sequences might not be exactly the same, otherwise it would be a straight up string-search algorithm.

This is fundamental in bioinformatics for two reasons:

These can be used to break cells apart from tissue, and also break up larger DNA or RNA molecules into smaller ones, suitable for sequencing.