BIOL 1107 Lecture Notes - Lecture 13: Telomerase, Primase, Dna Replication
Document Summary
Cell must separate the double strands of dna in order for a copy machine to come in and copy the dna. Dna synthesis starts at points of replication and proceeds in both directions from each starting point. The enzyme helicase catalyzes the breaking of hydrogen bonds between the two dna strands to separate them. The single-strand dna-binding proteins (ssbps) attach to the separated strands to prevent them from closing. Unwinding the dna helix creates tension further down the helix. To relieve the tension, the enzyme topoisomerase cuts and rejoins the dna downstream of the replication fork. Cleaves the dna in spots ahead of the helicase so that helicase can come in and push the dna molecules apart. Need a primer to start the dna replication process. The enzyme that creates the new strands must be activated (needs to be primed). This enzyme is not normally reactive unless pushed to be.
