BGEN 3020 Lecture Notes - Lecture 9: Philadelphia Chromosome, G Banding, Chronic Myelogenous Leukemia
3 Oct 2018
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Document Summary
Dr. hayflick established that normal cells cultured in vitro had a finite replicative period after which they withdrew from the cell cycle and become senescent. Cells that are immortal are: stem cells, tumour cells. Repetitive dna sequences found at the distal end of chromosomes (furthest from the centromere) Proposed roles: maintain integrity of dna ends, likened to caps at the end of shoelaces; chromosomes without telomeres are less stable, finishing dna replication, orienting chromosomes in the nucleus. As cells proliferate, the length of telomeres normally decrease with each cycle, functioning as a built in timer: except in tumour cells and stem cells, which are immortal. Lagging strand is stitched together and requires primers. End for lagging strand will be incomplete. Composed of protein and a template rna. Telomerase activity is increased in stem cells and cancer cells which are immortal. This information is important for diagnostic purposes: analysis of cancers and pre-natal screening.
