Anatomy and Cell Biology 4429A Lecture Notes - Lecture 17: Antioxidant, Cysteine, Telomerase

• School: Western University
• Department: Anatomy and Cell Biology
• Course: Anatomy and Cell Biology 4429A
• Professor: Paul Walton

Document Summary

17: senescence: by dividing too often or exposure to damaging environment. Wi-38 cell line most used, used for vaccines. Ha(cid:455)fli(cid:272)k"s (cid:272)ells do(cid:374)"t die (cid:271)ut the(cid:455) stop di(cid:448)idi(cid:374)g. Cellular senescence: older cells = increased sabg. Increased expression of p21 (inhibits almost all) and p16 (cyclin d inhibitor) Replicative senescence: stop dividing after a specific number of divisions: telomeres, b(cid:396)eakage a(cid:374)d fusio(cid:374), (cid:894)(cid:271)(cid:396)eakage (cid:449)ould(cid:374)"t al(cid:449)a(cid:455)s happe(cid:374) (cid:449)he(cid:396)e (cid:272)h(cid:396)o(cid:373)oso(cid:373)e (cid:271)(cid:396)oke(cid:895) If the(cid:455) do(cid:374)"t stop di(cid:448)idi(cid:374)g: e(cid:374)d to e(cid:374)d fusio(cid:374)s (cid:271)e(cid:272)ause the(cid:455) (cid:272)a(cid:374)"t (cid:373)ai(cid:374)tai(cid:374) the telo(cid:373)e(cid:396)es. The structure of the telomere: telomeric sequences: 6 base repeats (ttaggg), thousands of copies; overhanding strand tucks in to form displa(cid:272)e(cid:373)e(cid:374)t loop. Ch(cid:396)o(cid:373)oso(cid:373)es do(cid:374)"t ha(cid:448)e e(cid:374)ds, (cid:271)ut a loop that protects the ends of chromosomes. Telomeres are protective: yeast would use linear dna as food and got degraded, put bett(cid:455) bla(cid:272)k(cid:271)u(cid:396)(cid:374)"s telo(cid:373)e(cid:396)i(cid:272) se(cid:395)ue(cid:374)(cid:272)es o(cid:374) the li(cid:374)ea(cid:396) dna a(cid:374)d (cid:449)he(cid:374) i(cid:374)t(cid:396)odu(cid:272)ed i(cid:374)to yeast they were protected.