Photosynthesis160-page3

Photosynthesis160-page3 - Stomata structure will be...

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Photosynthesis - 3 1 . Water Water is the hydrogen and electron donor for the process of photosynthesis. Water is obtained from the environment, absorbed by roots and conducted throughout the plant in the xylem of the vascular system. Water needed for photosynthesis is but one of the demands for water in plants. Light energy is used to split water molecules, forming 2H + , 2e - , and Oxygen ( 1 / 2 O 2 ) during the process of photosynthesis. 2 . Carbon Dioxide Carbon dioxide provides the carbon source for manufacturing the carbohydrates in photosynthesis. Carbon dioxide diffuses from the atmosphere through pores in leaf surfaces, called stomata, which are formed by a pair of guard cells. The carbon dioxide then diffuses to the photosynthetic cells of the leaf mesophyll. The rate of diffusion of carbon dioxide and availability of carbon dioxide often limit the rate and amount of photosynthesis that occurs in a plant.
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Unformatted text preview: Stomata structure will be observed in the laboratory. 3 . Chloroplasts Photosynthesis occurs in chloroplasts. Recall that the chloroplast has a double membrane with a series of internal stacked membranes. Light energy is captured by the photosynthetic pigments located on the special membranes in the chloroplast called thylakoids, which are folded into disk-shaped stacks called grana. The interior compartments of thylakoids serve as reservoirs for hydrogen ions (H + ) that are needed for producing ATP. The reactions of photosynthesis that are involved in the transformation of light energy to chemical energy are called the light-dependent reactions. The reactions needed to produce carbohydrates occur in the stroma region of the chloroplast. Enzymes are located in the stroma. These reactions are known as the Calvin-Benson cycle or light-independent reactions....
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