LSCI 204 Lecture Notes - Lecture 14: Ribonucleoside, Proofreading, 2 On
8 Feb 2018
School
Department
Course
Professor
Document Summary
Dna replication happens during the s phase to g2. A disease that arises from a defect in one of several genes encode dna synthesis and repair enzymes. The happy tree, camptotheca acuminata, contains camptothecin, a substance used to treat cancer. Camptothecin inhibits cancer by blocking an important part of the replication machinery. Genetic information must be accurately copied every time a cell divides. Replication has to be extremely accurate: one error per million bp leads to 6400 mistakes every time a cell divides, which would be catastrophic. Replication also takes place at high speed: e. coli replicates its dna at a rate of 1000 nucleotides per second. Three proposed models of replication are conservative replication, dispersive replication, and semiconservative replication. Conservative replication: the entire double-stranded dna molecule serves as a template for a whole new molecule of dna, the original dna molecule is fully conserved during replication. None of the original molecule is conserved.
