DNA Replication Serving the Hereditary Function

Overview Manufacture of an exact copy of the DNA contained within a cell Required to occur prior to cell division Occurs only once in the life of a cell.

Overview Semi-conservative Hershey-Chase experiment Each daughter molecule is half old and half new Errors = mutation

Base Pairing A=T –Two H Bonds G=-C –3 H bonds Number of A=T Number of G=C

Types of mutations Substitution Deletion –Can cause frame shift Addition –Can cause frame shift

Major Components Involved Helicases Topoisomerases Single stranded binding proteins (SSB) Primase DNA Polymerase III DNA Polymerase I DNA Ligase

Steps Open the two complementary strands Copy leading strand –Towards replication fork Copy lagging strand –Away from replication fork Seal gaps

DNA Recipe function Transcription –Copy DNA into RNA –Nucleus in eukaryotic cells Translation –Read genetic code in RNA –Produce protein –Cytoplasm –Ribosomes