LIFESCI 3 Chapter Notes - Chapter 11.5: Terf2, Tinf2, Exosphere
Document Summary
Eukaryotic cells have to replicate the ends of linear chromosomes. Telomeres and telomerase solve the end replication problem in eukaryotes. End replication problem: when the rna primer at the extreme end is removed for replacement with dna there is no 3" terminus for dna polymerase to extend from. Single stranded gap can"t be converted to duplex dna. Genetic information in the gap will be lost in the next round of replication ends will progressively shorten until genes near the ends are entirely lost. Does not occur in circular dna with no ends. Chromosomes broken in two can heal by joining the chromosome ends creating a chromosome with two centromeres. During cell division chromosomes are pulled to opposite poles breaking the chromosomes another round of healing. Healing and breaking chromosome rearrangements, loss of genetic info and cell death. Ends of normal chromosomes do not join together by the healing process.
