PHOTOSYNTHESIS
PHOTORESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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C4 plants have stomata that are open only at night.
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C4 plants do not undergo the Calvin cycle.
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C4 plants use PEP-carboxylase for initial carbon dioxide fixation.
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C4 plants are adapted to cold wet environments.
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Detailed explanation-1: -RuBisCO takes up oxygen to perform photorespiration when carbon dioxide concentration is low. In C4 plants, since carbon dioxide concentration is high at the RuBisCO site thus, photorespiration is highly reduced. C4 plants possess special leaf anatomy called ‘Kranz anatomy’ and undergo the C4 pathway of photosynthesis.
Detailed explanation-2: -Under high temperature, high light, and the current CO2 concentration in the atmosphere, the C4 pathway is more efficient than C3 photosynthesis because it increases the CO2 concentration around the major CO2 fixating enzyme Rubisco. The oxygenase reaction and, accordingly, photorespiration are largely suppressed.
Detailed explanation-3: -C3 plants include around 95% of the shrubs, trees, and plants. While C4 plants are defined as the plants that use the C4 pathway during the dark reaction. The chloroplasts of these plants are dimorphic and unlike C3 plants the leaves of C4 plants possess kranz anatomy. C4 plants include around 5% of plants on earth.
Detailed explanation-4: -What is the role of PEP carboxylase in C4 and CAM plants? PEP carboxylase is essential for carbon fixation in C4 and CAM plants. It is present in the mesophyll cells. It catalyses the initial carbon fixation where PEP acts as an acceptor for CO2, and produces OAA.
Detailed explanation-5: -Explanation: Due to high rate of photosynthesis and reduced rate of photorespiration, C4 plants are more efficient than C3 plants. C4 plants have special leaf anatomy called ‘Kranz anatomy’. It have less CO2 compensation points and chlorophyll concentration is more than in C3 plants.