1. Yes, discussions this week; Exams back Friday

2. CB 36.2 Water and minerals move up from the ground in xylem, Sugars move down, up and/or laterally via phloem.

3. CB 36.13 What moves the water through the xylem? Transpiration, Adhesion, Cohesion, and Tension

4. Stomata on the underside of a leaf

5. CB 35.9 Water conducting cells of Xylem: vessels and tracheids (types of sclerenchyma) 100  m

6. CB 35.12 and.13 In roots the vascular bundle is in the center

7. CB 35.16 Radially arranged vascular bundle in a stem Xylem on inside Phloem on outside

8. water transport limits plant growth

9. xylem phloem More xylem is needed for more water transport: secondary growth

10. CB 35.10 Primary vs. secondary growth

11. CB 35.18 Primary growth in a stem

12. CB 35.18 Secondary growth: a vascular meristem (cambium) forms between the xylem and phloem

13. CB 35.18 Secondary growth: new xylem to the inside, new phloem to the outside

14. Secondary xylem (wood) and phloem

15. CB 35.20 Some additional cells help form the bark and fill in the increasing circumference

16. xylem phloem Xylem is tough, and full of lignin- inhibits the ability to use plants to produce biofuels

17. U.S. Energy use in 2005 http://www.sciencemag.org/sciext/sustainability/http://www.sciencemag.org/sciext/sustainability/ Science 9 February 2007:Vol. 315. no. 5813, pp. 796 - 798 Units are in quads; 1 quad = 1015 British thermal units = 1.055 exajoules

18. ~28% of U.S. energy is used in transportation http://www.eia.doe.gov/kids/energyfacts/uses/transportation.htmlhttp://www.eia.doe.gov/kids/energyfacts/uses/transportation.html U.S. Department of Energy, Transportation Energy Data Book: Edition 26-2007.

19. In 2005, there were almost 239 million vehicles (cars, buses, and trucks) in the United States. http://www.eia.doe.gov/kids/energyfacts/uses/transportation.htmlhttp://www.eia.doe.gov/kids/energyfacts/uses/transportation.html U.S. Department of Energy, Transportation Energy Data Book: Edition 26-2007.

20. Automobiles, motorcycles, trucks, and buses drove nearly 3.0 trillion miles in 2005. That’s almost 1/12 th the distance to the nearest (non-sun) star. It’s like driving to the sun and back 13,440 times. Transportation fuel use http://www.eia.doe.gov/kids/energyfacts/uses/transport ation.htmlhttp://www.eia.doe.gov/kids/energyfacts/uses/transport ation.html U.S. Department of Energy, Transportation Energy Data Book: Edition 26-2007.

21. http://www.eia.doe.gov/kids/energyfacts/uses/transportation.html http://www.eia.doe.gov/kids/energyfacts/uses/transportation.html U.S. Department of Energy, Transportation Energy Data Book: Edition 26-2007. Vehicle Energy Use

22. World Primary Energy Supply 2004 http://www.sciencemag.org/sciext/sustainability/

23. Research money spent on alternative energy http://www.sciencemag.org/sciext/sustainability/ http://www.sciencemag.org/sciext/sustainability/ Science 9 February 2007: Vol. 315. no. 5813, pp. 782 - 783

24. Ethanol vs Gasoline prices http://www.sciencemag.org/sciext/sustainability/

25. Biofuel production http://www.sciencemag.org/sciext/sustainability/

26. CB 5.7 Cellulose, sugars as structural support

27. CB 5.8 The major component of plant cell walls is cellulose

28. Fermentation: break down sugar to ethanol

29. http://www.iogen.ca/images/m1 _fuel_cycle2.jpg

30. Lignin: a complex branched, aromatic polymer

31. http://www.ccrc.uga.edu/~mao/intro/ouline.htm Lignin cross-links cellulose fibers and makes secondary walls waterproof

32. Nature Biotechnology 20, 557 - 558 (2002) Lignin removal is necessary for cellulose processing

33. Loosening lignin's grip on biofuel production Clint Chapple, Michael Ladisch & Rick Meilan Nature Biotechnology 25, 746 - 748 (2007) Treatment efficiencies of untreated transgenic biomass are comparable to that of unmodified biomass subjected to pretreatment

34. xylem Research is ongoing to produce woody and non-woody plants with decreased lignin to improve the efficiency of biofuel production

35. Yes, discussions this week; Exams back Friday