Polymerase Memes

The molecular horror of transcription. During RNA synthesis, thymine (T) in DNA gets replaced with uracil (A) in RNA. The poor RNA polymerase is just following protocol, but to an outside observer it looks like pure molecular panic. That moment when your entire job is to replace T with A and you realize you've got a string of ten thymines to convert. No wonder it's screaming. Graduate students in molecular biology labs feel this on a spiritual level during PCR reactions.