RNA Primer synthesis and Primer-dependent DNA Synthesis
Most DNA
polymerases are primer-dependent, that is,
they require a free 3' end to begin nucleotide
attachment. In prokaryotes, a short RNA Primer
is synthesized chemically from the template strand by an
RNA Primase. This provides the necessary 3' end.
Figure © 2012 TA Brown, Introduction to Genetics (1st ed.); additional text © 2012 by Steven M. Carr