What are dark and light reactions in photosynthesis?

C3 plants have the disadvantage that in hot dry conditions their photosynthetic efficiency suffers because of a process called . When the CO2 concentration in the drops below about 50 ppm, the catalyst that helps to fix carbon begins to fix oxygen instead. This is highly wasteful of the energy that has been collected from the light, and causes the rubisco to operate at perhaps a quarter of its maximal rate.

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Light and dark reactions in photosynthesis Photosynthesis is divided into two parts: 1

4 Answers - What are the phases of photosynthesis?

Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Benison Cycle, and it occurs in the stroma. ATP provides the energy while NADPH provides the electrons required to fix the CO2 (carbon dioxide) into carbohydrates.







26/11/2015 · What are the phases of photosynthesis

The drawback to C4 photosynthesis is the extra energy in the form of that is used to pump the 4-carbon acids to the bundle sheath cell and the pumping of the 3-carbon compound back to the mesophyll cell for conversion to PEP. This loss to the system is why C3 plants will outperform C4 plants if there is a lot of water and sun. The C4 plants make some of that energy back in the fact that the rubisco is optimally used and the plant has to spend less energy synthesizing rubisco.

Photosynthesis is the process by which plants and other things make food
In the Light-independent or dark reactions the enzyme RuBisCO captures ..

Dark Reactions of Photosynthesis: The Calvin-Benson …

The connection to hot and dry conditions comes from the fact that all the plants will close their stomata in hot and dry weather to conserve moisture, and the continuing fixation of carbon from the air drops the CO2 dramatically from the atmospheric concentration of nominally 380 ppm (2004 value). If the CO2 compensation point is lower on the above scale, the plant can operate in hotter and dryer conditions. The limits are placed by the fact that begins to fix oxygen rather than CO2, undoing the work of photosynthesis. C4 plants shield their rubisco from the oxygen, so can operate all the way down to essentially zero CO2 without the onset of photorespiration.

The Dark reaction of photosynthesis is purely enzymatic and it is slower than the light reaction.

Light and Dark Reactions in Photosynthesis Written by tutor Kathie Z

These intermediates are characterized by their resistance to so that they can operate in higher temperatures and dryer environments than . At right, the ranges of CO2 compensation points for the three types of plants are shown. These compensation points are the values at which the plants cease to provide net photosynthesis.

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Photosynthetic: Light reactions/Dark reactions | New …

Moore, et al. point to Flaveria (Asteraceae), Panicum (Poaceae) and Alternanthera (Amarantheceae) as genera that contain species that are intermediates between C3 and C4 photosynthesis. These plants have intermediate leaf anatomies that contain bundle sheath cells that are less distinct and developed than the .