BIOS 20175 Lecture Notes - Lecture 6: Ionizing Radiation, Hayflick Limit, Reverse Transcriptase
25 Jul 2020
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Importance of telomeres: disposable repeats at the end of dna that get shorter after each division . When they become too short they will prevent replication, leading to senescent cells or triggering apoptosis. Hayflick limit : number of times dna can divide before the telomere stops replication. Telomerase : contains a rna primer and a reverse transcriptase enzyme that allows for the addition of repetitive sequences to be added to the end of newly replicated dna = Mutation- any alteration to the dna sequence that changes an organism"s. Inherited via germline mutations while acquired are via somatic mutations. Somatic mutations are not passed onto offspring while germ- line mutations are. Physical mutagensex: ionizing radiation, which can lead to double stranded breaks. Uv light leads to pyrimidine primers on the same side of the. Reactive chemical mutagens: reactive chemicals can covalently alter bases, can cause cross-linking or strand breaks. Dna polymerase, when it doesn"t do its job.
