Yes, discussions this week; Exams back Friday

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Yes, discussions this weekExams back Friday
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CB 36.2
Water and minerals move up from the ground in
xylem, Sugars move down, up and/or laterally via
phloem.
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CB 36.13
What moves the water through the
xylem?Transpiration, Adhesion, Cohesion,
andTension
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Stomata on the underside of a leaf
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100 ?m
Water conducting cells of Xylem
vesselsandtracheids(types of sclerenchyma)
CB 35.9
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CB 35.12 and .13
In roots the vascular bundle is in the center
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Phloem on outside
Xylem on inside
Radially arranged vascular bundle in a stem
CB 35.16
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water transport limits plant growth
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More xylem is needed for more water transport
secondary growth
phloem
xylem
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CB 35.10
Primary vs. secondary growth
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Primary growth in a stem
CB 35.18
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Secondary growtha vascular meristem (cambium)
forms between the xylem and phloem
CB 35.18
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Secondary growthnew xylem to the inside, new
phloem to the outside
CB 35.18
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Secondary xylem (wood) and phloem
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Some additional cells help form the bark and fill
in the increasing circumference
CB 35.20
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Xylem is tough, and full of lignin- inhibits the
ability to use plants to produce biofuels
phloem
xylem
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U.S. Energy use in 2005
Units are in quads 1 quad 1015 British thermal
units 1.055 exajoules
http//www.sciencemag.org/sciext/sustainability/
Science 9 February 2007Vol. 315. no. 5813, pp.
796 - 798
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28 of U.S. energy is used in transportation
http//www.eia.doe.gov/kids/energyfacts/uses/trans
portation.html U.S. Department of Energy,
Transportation Energy Data Book Edition 26-2007.
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In 2005, there were almost 239 million vehicles
(cars, buses, and trucks) in the United States.
http//www.eia.doe.gov/kids/energyfacts/uses/trans
portation.html U.S. Department of Energy,
Transportation Energy Data Book Edition 26-2007.
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Automobiles, motorcycles, trucks, and buses drove
nearly 3.0 trillion miles in 2005. Thats almost
1/12th the distance to the nearest (non-sun)
star. Its like driving to the sun and back
13,440 times.
Transportation fuel use
http//www.eia.doe.gov/kids/energyfacts/uses/trans
portation.html U.S. Department of Energy,
Transportation Energy Data Book Edition 26-2007.
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Vehicle Energy Use
http//www.eia.doe.gov/kids/energyfacts/uses/trans
portation.html U.S. Department of Energy,
Transportation Energy Data Book Edition 26-2007.
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World Primary Energy Supply 2004
http//www.sciencemag.org/sciext/sustainability/
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Research money spent on alternative energy
http//www.sciencemag.org/sciext/sustainability/S
cience 9 February 2007 Vol. 315. no. 5813, pp.
782 - 783
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Ethanol vs Gasoline prices
http//www.sciencemag.org/sciext/sustainability/
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Biofuel production
http//www.sciencemag.org/sciext/sustainability/
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CB 5.7
Cellulose, sugars as structural support
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CB 5.8
The major component of plant cell walls is
cellulose
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Fermentation break down sugar to ethanol
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http//www.iogen.ca/images/m1_fuel_cycle2.jpg
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Lignin a complex branched, aromatic polymer
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Lignin cross-links cellulose fibers and makes
secondary walls waterproof
http//www.ccrc.uga.edu/mao/intro/ouline.htm
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Lignin removal is necessary for cellulose
processing
Nature Biotechnology 20, 557 - 558 (2002)
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Treatment efficiencies of untreated transgenic
biomass are comparable to that of unmodified
biomass subjected to pretreatment
Loosening lignin's grip on biofuel production
Clint Chapple, Michael Ladisch Rick Meilan
Nature Biotechnology 25, 746 - 748 (2007)
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Research is ongoing to produce woody and
non-woody plants with decreased lignin to improve
the efficiency of biofuel production
xylem
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Yes, discussions this weekExams back Friday