Given below are two statements:
Statement I: In C3 plants, some O2 binds to RuBisCO, hence CO2 fixation is dec

Question

Given below are two statements:
Statement I: In C3 plants, some O2 binds to RuBisCO, hence CO2 fixation is decreased.
Statement II: In C4 plants, mesophyll cells show very little photorespiration while bundle sheath cells do not show photorespiration.

In the light of the above statements, choose the correct answer from the option given below:

Accepted Answer

According to the textbook:
- Statement I is Correct: In C3 plants, RuBisCO has an affinity for both CO2 and O2. Some O2 binds to RuBisCO, and hence CO2 fixation is decreased, leading to a process called photorespiration .
- Statement II is Incorrect: In C4 plants, photorespiration does not occur . Furthermore, the mesophyll cells of C4 plants lack the enzyme RuBisCO entirely , so they cannot perform photorespiration (which is catalysed by RuBisCO). The bundle sheath cells contain RuBisCO, but the C4 mechanism increases intracellular CO2 concentration there, ensuring the enzyme acts as a carboxylase and preventing photorespiration .

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