1. Eukaryotic Chromosome Organization

4. Chromosome Organization if all of the DNA was stretched out, it would measure 1.8 metres in length How does it fit into a typical human cell nucleus, 10 micrometres in diameter? there is a hierarchical organization DNA is coiled around a group of 8 stabilizing proteins called histones, forming nucleosomes

5. Chromosome Organization See animation: http://www.biostudio.com/c_%20education%20mac.htm http://www.biostudio.com/c_%20education%20mac.htm Histones Linkers Nucleosome (8 histones) Solenoid (6 nucleosomes) Supercoil

6. Chromosome Organization Solenoid = a group of 6 nucleosomes coiled into chromatin fibres chromatin fibres fold into final chromatin structure through supercoiling.

7. Prokaryotic DNA

9. primary DNA is single circular chromosome supercoiling happens in prokaryotes plasmids are other circular pieces of DNA contained in prokaryotes plasmids can be exchanged through conjugation

10. Telomeres

11. telomeres are non-coding, repetitive sequences at the ends of chromosomes

12. Telomeres

14. during replication, the last 5’ end primer on the lagging strand is removed but not replaced with DNA This shortens the telomeres on each subsequent replication cycle

15. »http://www.youtube.com/watch?v=8_bNf Qd7Smc

16. Telomeres after many replications, telomeres will eventually disappear, allowing coding DNA to be damaged cell senescence- deteriorated functioning with age as chromosomes shorten Hayflick limit = total number of times a normal cell can divide (about 50 in humans)

17. Dolly the Sheep

18. Anti-Aging

19. Dani Walker “Stop Aging Now TS-X Telomere Supplement”

20. 20 Homework 1.Read 6.5 for review. 2.Read 6.6 & answer: a.What is the DNA sequence found in telomeres? b.What is telomerase? What is its function? Where is it found? c.What is the role of telomeres in aging? d.What is the role of telomeres in cancer? e.Complete the tables provided.