Photosynthesis can be broadly separated into:

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Photosynthesis can be broadly separated into
light reactions - light dependent dark
reactions - light independent
Light reactions are involved in the
oxidation of water to oxygen reduction of NADP
to NADPH and ATP occur in thylakoid
membranes Dark reactions use NADPH and ATP to
fix CO2 into CH2O occur in stroma matrix of
chloroplasts
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Lecture 21 Photosynthetic pathways and the
environment.  
By the end of this lecture you should be able
to Describe the initial steps of carbon
fixation, including the contrasting carboxylase
and oxygenase function of RUBISCO. Concepts and
terms Calvin cycle, photorespiration Describe
the three different photosynthetic
pathways. Concepts and terms C3, C4, CAM,
bundle sheath cell, malate, Kranz
anatomy. Describe how these different
photosynthetic pathways respond to key
environmental variables.  
Discuss the relationship between the different
photosynthetic pathways and geographic
distribution. Assigned reading Chapter 10 in
the text. Reference Chapter 15 Photosynthesis,
In Terrestrial Plant Ecology, 3rd ed., Barbour
et al.
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Figure 10.17 The Calvin cycle (Layer 1)
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RUBISCO
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Photorespiration
http//treebiol.forest.wisc.edu/forestry415/TreeSt
ructure/leaves/darkReactions/photoresp.htm
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http//biog-101-104.bio.cornell.edu/BioG101_104/tu
torials/botany/stomata2.html
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CAM pathway e.g., pineapple, cacti
C4 pathway e.g., corn, sugarcane
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Figure 10.17 The Calvin cycle (Layer 1)
Photosynthetic pathways C3, C4, CAM
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C3
Krantz anatomy
C4
C4 phtosynthetic pathway
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Leaf x.s. of Poa C3 http//www.uri.edu/artsci/b
io/plant_anatomy/100.html
Note that the bundle sheath cells are small and
contain no specialized chloroplasts.
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Leaf x.s. of Bouteloua C4 http//www.uri.edu/ar
tsci/bio/plant_anatomy/99.html
bundle sheath the layer of tightly-packed cells
that surround the vascular tissue in leaves
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Figure 10.18 C4 leaf anatomy and the C4 pathway
PEP phosphoenolpyruvate
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Crassulacean Acid Metabolism (CAM)
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Crassulacean Acid Metabolism (CAM) http//www.teac
hing-biomed.man.ac.uk/student_projects/2000/mnby7l
mg/lectures/cam.html
PEP phosphoenolpyruvate
OAA oxaloacetate
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Diurnal cycle for a typical CAM plant like Agave
desertii.
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Figure 10.19 C4 and CAM photosynthesis compared
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• grass taxa that are C4 B.
  dicotyledon taxa that are C4.
• From Lambers et al.