I have a question regarding the DNA synthesis that takes place on the lagging strand of a DNA molecule.
I'm aware that replication on the lagging strand is discontinuous due to the anti-parallel nature of DNA's structure, and that primase lays down RNA primers, to whose free 3' DNA polymerase adds nucleotides in the direction opposite of the DNA polymerase on the leading strand.
However, what I fail to understand is how the very first RNA primer on the lagging strand "works", for lack of a better word. How does primase know where to place the primer? Also, more importantly, how does DNA polymerase know when to stop extending the nucleic acid chain, since there are no RNA primers ahead of it to "bump" into? Where does it stop?
Also, consequently, I know that in a replication "bubble" there are two replication forks, and that on each strand, one end acts as a lagging strand and the other as a leading strand. How does this work? How are the strands that are being separately and in different ways later attached; that is, where does each one stop being replicated?
Any help is greatly appreciated, as I have a test on this material on Friday. Many thanks in advance!