Elongation of the RNA transcript

The process is similar to that of DNA strand elongation: the two terminal PO4 groups are clipped from the new ribonucleotide, and the 5' terminus is added to the old 3' terminus. The RNA growth thus occurs in the 5'3' direction, like DNA.

Figure © 2012 TA Brown, Introduction to Genetics (1st ed.); additional text © 2014 by Steven M. Carr