Complex sentence: By convention, RNA sequences are written in a 5'to 3' direction, where the 5'end is the part of the RNA molecule that is transcribed first, and the 3' end is transcribed last.
Split into simpler sentences: By convention, RNA sequences are written in a 5'to 3' direction. The 5'end is the part of the RNA molecule that is transcribed first, and the 3' end is transcribed last.