Photosynthesis
- Ferredoxin is a constituent of
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In PSI, when the electron passes from ferredoxin and plastoquinone, the electron loses sufficient energy to form ATP from ADP and inorganic phosphate.
Correct Option: A
In PSI, when the electron passes from ferredoxin and plastoquinone, the electron loses sufficient energy to form ATP from ADP and inorganic phosphate.
- With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?
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In C3 plants photosynthesis decreases at higher temperature due to increased photorespiration. C4 plants have higher temperature optimum because of the presence of enzyme called pyruvate phosphate dikinase, which is sensitive to low temperature.
Correct Option: B
In C3 plants photosynthesis decreases at higher temperature due to increased photorespiration. C4 plants have higher temperature optimum because of the presence of enzyme called pyruvate phosphate dikinase, which is sensitive to low temperature.
- A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant?
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C4 plants are adapted to hot and dry climate and lack photorespiration due to Kranz anatomy and have Greater productivity of biomass.
Correct Option: B
C4 plants are adapted to hot and dry climate and lack photorespiration due to Kranz anatomy and have Greater productivity of biomass.
- Bundle sheath cells
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In C4 plants, bundle sheath cells are rich in RUBISCO, but lack PEPcase. The CO2 released in the bundle sheath cells enters the C3 or the Calvin pathway, common to all plants. Thus, the basic pathway that results in the formation of sugars, the calvin pathway is common to the C3 and C4 plants.
Correct Option: A
In C4 plants, bundle sheath cells are rich in RUBISCO, but lack PEPcase. The CO2 released in the bundle sheath cells enters the C3 or the Calvin pathway, common to all plants. Thus, the basic pathway that results in the formation of sugars, the calvin pathway is common to the C3 and C4 plants.
- A process that makes important difference between C3 and C4 plants is :
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Photorespiration is absent is C4 plants. Photorespiration does not produce energy or reducing power. Rather, it consumes energy. Further, it undoes the work of photosynthesis. There is 25% loss of fixed CO2. Therefore, photorespiration is a highly wasteful process. This happens only in case of C3 plants.
Correct Option: D
Photorespiration is absent is C4 plants. Photorespiration does not produce energy or reducing power. Rather, it consumes energy. Further, it undoes the work of photosynthesis. There is 25% loss of fixed CO2. Therefore, photorespiration is a highly wasteful process. This happens only in case of C3 plants.
