Question

In C4 plants, the CO 2 concentration in the chloroplast is increased by initially fixing CO 2 into a four‑carbon compound in the mesophyll cell and then releasing it later in the bundle sheath cell.

The enzyme 1.____ catalyzes the initial CO2 fixation in the mesophyll cell and generates 2.____

1. options : rubisco, magic enzyme, phosphoenolpyruvate carboxykinase, phosphoenolpyruvate carboxylase, pyruvate carboxylase

2. options : malate, pyruvate, 3-phosphoglycerate, oxaloacetate

Answer 1

Ans- in C4 plants, the light-dependent reaction takes place in the mesophyll cell, and the Calvin cycle takes place in the bundle sheath cells.

In C4 plant, the initial CO₂ fixation takes place in mesophyll cells and form a 4 carbon organic acid known as oxaloacetate. This reaction is catalyzed by phosphoenolpyruvate carboxylase enzyme. This oxaloacetate is further converted into malate by malate dehydrogenase. This malate transported to the bundle sheath cell, and inside bundle sheath cells malate is broken and release a molecule of CO₂.

The enzyme phosphoenolpyruvate carboxylase catalyzes the initial CO2 fixation in the mesophyll cell and generates oxaloacetate.

so correct answer 1- phosphoenolpyruvate carboxylase 2- oxaloacetate