Biology 1001A Lecture Notes - Lecture 8: Telomerase, Dna Replication, Germ Cell
B1001a Sept. 27/2016
Lecture 05: Inheritance of Sameness
- DNA pol III a ol eted a hroosoe addig o to the 3’ ed of it. All ko polerases i
the world can only moe fro the 5’ ed to the 3’ed o the e strad
- DNA replication begins at the origin (sequences of DNA). Bi-directional replication: Goes in opposite
direction
- DNA replication is semi conservative, semi discontinuous, and bi-directional
- In most active cells (most of the time) telomerase is not active because they want their chromosomes
to shorten which allows them to gage how much replications they have left. Once telomeres reach a
minimum length, cells know that they have replicated too much times (accumulate too many mutations)
so they program cell death.
- In cancer cells, telomerase is active so they can divide rapidly.
- Stem cells also express telomerase
- Germ cells also express telomerase (you want to give your babies young chromosomes with long
telomeres, not old chromosomes w/ shortened telomeres)
- Meristematic cells express telomerase
- Any cells that are actively dividing express telomerase.
- *Teloerase atiit is regulated it is ot just o or off, the a e like half-o
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Document Summary
Dna pol iii (cid:272)a(cid:374) o(cid:374)l(cid:455) e(cid:454)te(cid:374)d a (cid:272)hro(cid:373)oso(cid:373)e (cid:271)(cid:455) addi(cid:374)g o(cid:374) to the 3" e(cid:374)d of it. (cid:894)all k(cid:374)o(cid:449)(cid:374) pol(cid:455)(cid:373)erases i(cid:374) the world can only mo(cid:448)e fro(cid:373) the 5" e(cid:374)d to the 3"e(cid:374)d o(cid:374) the (cid:374)e(cid:449) stra(cid:374)d(cid:895) Dna replication begins at the origin (sequences of dna). Dna replication is semi conservative, semi discontinuous, and bi-directional. In most active cells (most of the time) telomerase is not active because they want their chromosomes to shorten which allows them to gage how much replications they have left. Once telomeres reach a minimum length, cells know that they have replicated too much times (accumulate too many mutations) so they program cell death. In cancer cells, telomerase is active so they can divide rapidly. Germ cells also express telomerase (you want to give your babies young chromosomes with long telomeres, not old chromosomes w/ shortened telomeres) Any cells that are actively dividing express telomerase.