Which of the following is absent in C4 Plants:

Correct answer: D. CO2 Fixation in Mesophyll Cells

  • A. Calvin Cycle
  • B. Bundle Sheath Cells
  • C. PEP Carboxylase
  • D. CO2 Fixation in Mesophyll Cells

Explanation

In C4 plants, CO2 fixation occurs in the mesophyll cells, but it follows a unique pathway compared to C3 plants. C4 plants are adapted to minimize photorespiration by initially fixing CO2 in the mesophyll cells using the enzyme PEP Carboxylase, forming a four-carbon compound (oxaloacetate). This compound is then transported to the bundle sheath cells, where the Calvin cycle occurs. Therefore, the statement that CO2 fixation is absent in mesophyll cells is incorrect.The Calvin cycle is indeed present in C4 plants, but it occurs in the bundle sheath cells, not the mesophyll cells. Bundle sheath cells are essential for the Calvin cycle in C4 plants, and PEP Carboxylase is vital for the initial CO2 fixation. Thus, options A, B, and C are incorrect.

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