GENETICS - 1/30 GENETICS replication contd begin...

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1/30 GENETICS- replication contd.- begin transription Telomerase carries around its own template that is used over and over again…. made out of RNA…get it’s a alignment by base- pairing its’ RNA with the part that’s hanging off….templates are relatively short and add about 6 nucleotides and then fall off and then connect and add the same sequence it added previously…. what it adds does not encode anything…it is useful in its uselessness…sacrificial DNA (can be lost without consequence)…now there is room for another okazaki fragment DNA pol Alpha adds a few nucleotides and then DNA pol delta attaches and goes all the way to the end and ligase connects the two fragments A lot of cells do not carry telomerase causing the cells to eventually stop dividing…cells shut down their capacity for division because they are losing too much genetic material when the telomores get short Cancer cells have an unlimited amount of telomerase causing the cells to continuously divide…other examples are germs and unicellular eukaryotes (where telomerase was discovered) Do not have active telomerases are somatic cells Wound healing requires cell division and cell division requires replication….the reason why as we get older, it takes longer for cuts to heal. Telomerase is a factor in aging but not the only reason or even a major reason Telomerase could be a target in anti- caner drugs Bacteria does not have this issue because it has a circular replication which means it fully replicates and has no need for telomerase MITOCHONDRIAL REPLICATION-has its own DNA which is circular, double stranded…separation for replication must start in the origin of replication… requires a primer which is made out of RNA…chemical and enzymatic part of it is same as we have seen Differences: carries DNA pol Y (gamma) (only one that carries this) and does all replication….replication is unidirectional (only one fork) and there is no lagging strand…DNA pol gamma makes the leading strand all the way around…ligase still comes in to close it up Other strand is strand specific…has a different origin and goes the opposite direction…unidirectional….must have a primer…both cases ¼ of the replication that usually happens TRANSCRIPTION only mRNA are translated while tRNA rRNA and snRNA are not
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GENETICS - 1/30 GENETICS replication contd begin...

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