BIOL 222 Lecture Notes - Lecture 12: Proofreading, Helicase, Chromosome
Document Summary
Biol 222 lecture 12 dna replication 2. Origin of replication fixed point where replication begins. Dnaa protein (initiator protein) binds to origin and unwinds dna. Ssdna binding protein (ssb) stabilizes single-stranded dna (ssdna) Dna helicase disrupts h bonds holding the two strands together at the replication fork. Primase an rna polymerase with a specific purpose and function: dnap requires duplex template for dna replication, primase synthesizes a short rna primer. Creates a short rna/dna duplex for replication: primer is extended by dnap iii, dnap can"t initiate without a primer. Grows in opposite direction of the replication fork: dnap iii functions as a dimer so that both strands are synthesized simultaneously. Lagging strand loops around 180 degrees so that it can be synthesized in the 5" to 3": several antibiotics target components of the replication machinery. Proof reading: dnap i and dnap iii posses 3" to 5" exonuclease activity that serves a proofreading function.
