NEETBotanyPhotosynthesis in Higher Plants
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Photorespiration is absent in C ₄ plants. Reason (R) : C ₄ plants have a mechanism that increases the concentration of CO ₂ at the enzyme site. In the light of the above statements, choose the most appropriate answer from the options given below :
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- B(A) is correct but (R) is not correct
- C(A) is not correct but (R) is correct
- DBoth (A) and (R) are correct and (R) is the correct explanation of (A)
Correct answer
D. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct as photorespiration does not occur in C ₄ plants. Reason (R) is also correct and explains the assertion. C ₄ plants lack photorespiration because they have a mechanism that increases the concentration of CO ₂ at the enzyme site. This takes place when the C ₄ acid from the mesophyll is broken down in the bundle sheath cells to release CO ₂ . This results in increasing the intracellular concentration of CO ₂ , which ensures that RuBisCO functions as a carboxylase minimizing the oxygenase acti