Topic: Replication of DNA Standard: Explain the role of DNA in storing and transmitting cellular information

2/4/14 How do you distinguish between DNA and RNA? How do you distinguish between DNA and RNA?

When & why does DNA have to replicate? Replicates during Interphase inside of the nucleus Replicates during Interphase inside of the nucleus Replicates so that there will be enough genetic information for the cell to divide Replicates so that there will be enough genetic information for the cell to divide Called Called“semi-conservative”replication

Semi-conservative replication (p. 333) 3 Phases 3 Phases –Unwinding –Base Pairing –Joining

DNA Replication: Step 1: Unwinding DNA helicase unwinds the DNA by breaking the hydrogen bonds between the bases DNA helicase unwinds the DNA by breaking the hydrogen bonds between the bases 2 single strands of 2 single strands of DNA remain

DNA Replication: Step 2: Base Pairing DNA polymerase catalyzes the addition of new base pairs DNA polymerase catalyzes the addition of new base pairs New base pairs are added to the end of the new DNA strand New base pairs are added to the end of the new DNA strand This way, the new strands of DNA are identical to the old ones This way, the new strands of DNA are identical to the old ones

DNA Replication: Step 2: Base Pairing One strand is the leading strand and the other is the lagging strand One strand is the leading strand and the other is the lagging strand The lagging strand The lagging strand is broken up into Okazaki fragments by DNA polymerase

DNA Replication: Step 2: Base Pairing The leading and lagging strands add new bases in opposite directions The leading and lagging strands add new bases in opposite directions Over all the Over all the direction of replication is the same

DNA Replication: Step 3: Joining Sections where DNA replication is complete finally join (bubbles fill in) Sections where DNA replication is complete finally join (bubbles fill in) Uses DNA Ligase to help seal the DNA strands Uses DNA Ligase to help seal the DNA strands

Practice Replication Parent Strand: ATC GCT GAT AGC TAG Parent Strand: ATC GCT GAT AGC TAG New Strand: TAG CGA CTA TCG ATC New Strand: TAG CGA CTA TCG ATC Parent Strand: CTT TAA ACC ATC GGA Parent Strand: CTT TAA ACC ATC GGA New Strand: GAA ATT TGG TAG CCT New Strand: GAA ATT TGG TAG CCT Parent Strand: GTA GGG CGC ATA CGT Parent Strand: GTA GGG CGC ATA CGT New Strand: CAT CCC GCG TAT GCA New Strand: CAT CCC GCG TAT GCA