Question

The first stable product identified in Calvin cycle of $C_3$ and $C_4$ plants are respectively

• A. 3-PGA and 3-PGA
• B. 3-PGA and OAA
• C. 1,3-di PGA and malate
• D. 3-PGA and malate

Answer 1

The correct option is A 3-PGA and 3-PGA

The first stable compound produced in Calvin cycle is a 3 carbon compound, that is 3 phosphoglyceric acid (PGA). Due to this, the Calvin cycle is also called as C${}_3$ cycle. In C${}_4$ plant, the first stable product is a 4 carbon compound, that is Oxaloacetic Acid (OAA). This oxaloacetic acid is then converted into malate, a 4 C compound. This 4 C compound then enters the bundle sheath cell where the Calvin cycle takes place in a chloroplast. Over here, the first stable product formed is 3 phosphoglyceric acid (PGA).

Thus, the correct answer is '3-PGA and 3-PGA.'