Question

Classification of a biosynthetic phase of dark reaction as $C_3$ and $C_4$ is primarily based on

• A. Intial $C{O}_2$ fixation
• B. Final $C{O}_2$ assimilation
• C. First CO${}_2$ receptor
• D. Number of ATP get consumed

Answer 1

The correct option is A Intial $C{O}_2$ fixation

The next phase of photosynthesis after the light reaction is the biosynthetic phase. In this, ATP and NADPH are used for synthesizing the food. This stage is also called the dark phase as it is independent of light but deals with the products of the light reaction. The first stable product formed in the C${}_3$ cycle is three carbon compound phosphoglyceric acid and in the C${}_4$ cycle is four carbon compound oxaloacetic acid. Thus, the classification of biosynthetic phase is primarily based on initial C0${}_2$ fixation

So, the correct answer is 'Initial C0${}_2$ fixation'.