Transcription (1-25-07)

Transcription (1-25-07) - Transcription Telomerase lines up...

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Transcription Telomerase- lines up with strand, then adds about 6 nucleotides at which point it let goes, moves down 6 nucleotides, then re-alligns itself and adds another 6 nucleotides, until there’s a pretty considerable overhang of DNA on the 3’ end. This enables another okazaki fragment where there couldn’t have been one before. So the shorter strand (5’ end) can lengthen. There is a limited number of divisions a eukaryotic cell can undergo; we know this is somehow due to the shortening of the telomeres. Cancer cells are one of the only known cells that can divide an unlimited number of times and they have “active” telomerase. Germ cells (reproductive) must also have active telomerase. Unicellular eukaryotes also must have active telomerase. Somatic cells don’t have active telomerase Mitochondria- have their own DNA (cicular, double-stranded); DNAPolymerase gamma (DNAP γ); Replication only occurs on the leading strand in mitochondria (only one fork that has only the leading strand); It’s okay because it’s relatively small, and doesn’t take that long to come back around. There are two origins of replication, and is specific to only one of the two strands (they are also at two different locations on the circle)
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This note was uploaded on 04/27/2008 for the course BIO 325 taught by Professor Saxena during the Fall '08 term at University of Texas.

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Transcription (1-25-07) - Transcription Telomerase lines up...

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