grow in the 5' 3' direction only
DNA synthesis, new nucleotides are added to the
existing 3' end by a 3'
5' phosphodiester bond (R
- O - P - O - R). The original 5' end
remains unmodified, and the polynucleotide "grows" by modification of
the 3' end, in the 5'3' direction. Biochemical syntheses of nucleic
acids occur only in the 5'3' direction.
Do not try to
understand this process in any other way!
Figure © 2010 PJ Russell, iGenetics 3rd ed.; all text material © 2011 by Steven M. Carr