Photorespiration

Photorespiration - Photorespiration Stomata and CO2...

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Photorespiration Stomata and CO 2 Concentration Stomata (singular stoma) are microscopic openings on the undersurface of leaves that allow gas exchange and water evaporation from inside the leaf. Because dehydration can be a serious problem, the stomata close when the plant is under water stress. When closed, CO 2 needed for the Calvin cycle cannot enter. A stoma can be seen in the diagram of a leaf below. CO 2 Fixation in C 3 Plants Plants that undergo photosynthesis as described above are called C 3 plants because the end result of CO 2 fixation is two 3-carbon molecules (PGA). In C 3 plants, CO 2 is fixed to RuBP to form a 6 carbon compound by the enzyme rubisco. When the concentration of CO 2 is low, oxygen will bind to the active site of rubisco. The  resulting reactions do not produce sugar and they consume ATP. In addition,  organic compounds that are involved in photosynthesis are broken down.  During photosynthesis, CO2 is fixed by the enzyme rubisco. During hot, dry conditions, the level of CO2 drops
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This note was uploaded on 12/15/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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Photorespiration - Photorespiration Stomata and CO2...

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