website/email

1. website/email http://mscwan.wordpress.com mscwan2@gmail.com

2. TEST: Tues. February 7th • identifying organelles and their functions • DNA structure (nucleotide base pairing) • protein synthesis (only at depth of textbook) • types of mutations (addition, deletion, substitution; positive, negative, neutral) • causes of mutations (mutagens) • how gene therapy works

3. TEST: Tues. February 7th • Questions?

4. recap • mutagens cause mutations in DNA • mutations = change in genetic sequence  proteins not made properly

5. recap • positive = beneficial to survival • negative = detrimental to survival • neutral = no effect on survival

6. recap • addition = insertion of an extra base • TACTGC  TACCTGC • deletion = removal of a base • TACTGC  TACTC • substitution = switching of a base • TACTGC  TAATGC

7. recap • gene therapy is a highly experimental procedure to correct mutations • insertion of healthy gene into cold virus, which carries the gene to target cells • cell must activate healthy gene to synthesize correct amounts of the healthy protein

8. mitosis & cancer 30 January 2012

10. question • How does each cell in the body get a complete set of DNA when a cell divides?

11. which stage? • longest stage of the cell cycle interphase

12. which stage? • spindle fibres pull chromosomes into a line metaphase

13. which stage? • nuclear membrane breaks down prophase

14. which stage? • spindle fibres contract and shorten anaphase

15. which stage? • condensation of chromatin into visible chromosomes prophase

16. which stage? • individual chromosomes not visible interphase

17. which stage? • nucleolus disappears prophase

18. which stage? • growth and DNA replication occurs interphase

19. which stage? • spindle forms prophase

20. which stage? • nuclear membranes start to re-form telophase

21. which stage? • spindle attaches to centromere prophase

22. which stage? • chromosomes aligned at cell equator metaphase

23. which stage? • spindle fibres start to disappear telophase

24. which stage? • sister chromatids pulled to opposite poles of the cell anaphase

25. which stage? • cell membrane pinches to divide cytoplasm and organelles cytokinesis

26. which stage? • one set of chromosomes at each pole of the cell telophase

27. which stage? • centromere pulled apart anaphase

28. which stage? • DNA loosely coiled so it can be transcribed into RNA interphase

29. which stage? • nucleolus reappears telophase

30. which stage? • shortest stage of mitosis anaphase *

33. “In Cell Division” song • http://www.youtube.com/watch?v=IlV9hExXZnM

34. question & discussion • Nina spent all summer tanning on the beach without any sunscreen. After feeling poorly for several months, she went to see a doctor, who told her that she had metastatic melanoma, and that there were tumours growing on her internal organs. How did she get cancer? How did it spread from her skin to her organs?

35. checkpoints

36. cancer • loss of cell cycle control (mutation in gene that codes for a checkpoint protein) • may lead to uncontrollable cell division

37. cancer

38. cancer

39. cancer • cancerous cells release chemicals that cause blood vessels to branch into tumour • nutrients delivered, tumour grows • cancerous cells may break away and be carried to other locations where they form a new tumour

40. cancer (extra) 30 January 2012

41. general facts • leading cause of death worldwide • lung, stomach, liver, colon and breast cancer cause the most cancer deaths each yr. • most frequent types of cancer differ between men and women. • About 30% of cancer deaths due to the five leading behavioural and dietary risks: high body mass index, low fruit and vegetable intake, lack of physical activity, tobacco use, alcohol use.

42. general facts • In the US, direct medical costs (total of all health expenditures): $102.8 billion

43. UV damage • “…key reaction on the DNA molecule that is linked to sunburn happens with astounding speed - in less than one picosecond.” • one picosecond = one trillionth of a second (10-12 seconds) http://www.scienceagogo.com/news/20070101164743data_trunc_sys.shtml

44. UV damage • “Badly damaged cells simply die - the effect that gives sunburn its sting.” • “… chronic damage creates mutations that lead to diseases such as skin cancer.” http://www.scienceagogo.com/news/20070101164743data_trunc_sys.shtml

45. UV damage • “UV-B light causes crosslinking between adjacent cytosine and thymine bases creating pyrimidine dimers. This is called direct DNA damage. • UV-A light creates mostly free radicals. The damage caused by free radicals is called indirect DNA damage.” http://en.wikipedia.org/wiki/DNA_repair#Types_of_damage

46. free radicals • atom or group of atoms with an odd (unpaired) number of electrons • highly reactive

48. free radicals • as molecules react with oxygen in cellular respiration, they become free radicals, which are highly unstable and highly reactive • free radical goes around cell, ‘stealing’ electrons from stable molecules, rendering them unstable

49. free radicals • antioxidants

50. eating grilled red meat cancer? • The Nature of Things • “Myth or Science?” • original air date: November 24, 2011 • http://www.cbc.ca/video/#/Shows/The_Nature_of_Things/1242300217/ID=2170768762