Originally posted by sonhouse
I see these illustrations in rags like Scientific American, there are some really nice new pieces about DNA and how they are activated or closed off, with methyl and acetalization, opening up the histones or closing them down and such. I wondered, from the images which shows the RNA and such wrapping around the now open DNA stretch, when that process is fin ...[text shortened]... t zipper back together or is it a one track read and then the whole thing chopped up in aptosis?
DNA only uncoils in small sections at a time, and generally only in specific locations. When it's done transcribing RNA it zips right back up again. DNA lasts about 30 years in most cells, meaning that even for a youngstrel like me (28), I'm quite literally a different person than I was as a child!
The RNA, on the other hand, is broken down pretty rapidly in the normal course of things.
[I should explain, for those who don't know, that DNA is transcribed
to RNA (specifically messenger RNA, or mRNA), which leaves the nucleus (in eukaryotes) and moves to the ribosome (normally on the rough endoplasmic reticulum). The RNA is translated
, in 3-base sections (called codons), by the ribosome, into a protein. Each codon codes for 1 amino acid (the building blocks of proteins). The act of lining up the right amino acids is facilitated by another class of RNA, called transfer RNA, or tRNA.]