1. DNA serves as the carrier of genetic information in both prokaryotes and eukaryotes (Devlin, 1997, 564). The flow of biological information goes from one class of nucleic acid (DNA) to another (RNA), with only minor exceptions, and goes from RNA to proteins. For this transfer to occur faithfully, each preceding macromolecule serves as a structure-specific template for the subsequent member of the sequence. DNA is a replicon - a molecule that can undergo self-replication, allowing it to make copies of itself during cell division so that it can pass these copies on to daughter cells, which inherit every property and characteristic of the original cell. In this way, DNA serves as genetic information, determining the properties of living cells by control of protein synthesis and transferring biological information from one generation to the next.
2. Because DNA is double stranded, each strand can act as a template for replication of the other strand (Devlin, 1997, 642). Replication is semiconservative, with each new double strand of DNA containing one old strand and one new strand (643). Each strand serves as a DNA polymerase template for the synthesis of a new strand. Primers are formed by primerases to initiate replication by assembling the first few nucleotides, generally using ribonucleotides for incorporation into primers. In mammalian cells, DNA polymerase ? catalyzes the synthesis of the leading strand, and DNA polymerase ? catalyzes synthesis of the lagging strand(654-655). Synthesis is initiated in eukaryotic cells by an autonomous replicating sequence. Synthesis is bidirectional, both strands being replicated at once, and the original strands separating as replication takes place. This is achieved by the helicase enzyme, which separates the strands (648). Because synthesis only occurs in the 5' to 3' direction, the first chain replicated is synthesized continuously, but the second chain is synthesized discontinu...