Question

Give a graphic outline of the biosynthetic phase of photosynthesis.

Answer 1

Hint:- It is independent of light but deals with the products of the light reaction, this stage is also called the dark phase. It takes place inside the chlorophyll stroma. Glucose is formed by using $ATP$ and $NADPH$ during this process.

Complete step-by-step solution:-
The biosynthetic process of photosynthesis occurs in the chloroplast stroma. Light from sunlight does not involve this operation. In this process, with the aid of hydrogen ions that are formed during light-dependent photosynthesis reactions, carbon dioxide is reduced to glucose. ATP and NADPH are used for synthesizing food in the biosynthetic process of photosynthesis. $CO_2$ is fixed to form a result of $CO_2$ fixation.

Fig: Biosynthetic phase of photosynthesis.

When carbon dioxide from the atmosphere reaches plant cells, the cycle begins. The first reaction catalyses an enzyme called rubisco, which binds $CO_2$ to a particular 5-carbon molecule called ribulose-1,5-bisphosphate (RuBP). A 6-carbon molecule is formed by this response, which then splits into two 3-carbon molecules. Carbon fixation is called this section of the cycle. This just implies that, like sugar, inorganic carbon is converted to organic molecules.

Additional information:
For biosynthesis or dark phases, there are two major pathways; the cycle of Calvin and the cycle of $C4$ dicarboxylic acid. CAM metabolism is a third pathway and is an intermediary between the two pathways. The plants with the Calvin cycle and the $C4$ dicarboxylic acid cycle are called $C3$ and $C4$ plants, respectively.

Note:- The light reaction is unable to take place in the absence of light. It is observed that even the biosynthetic process stops (although it goes on for a while) after some time. This demonstrates that it is indirectly light dependent and requires that the light reaction products proceed.