Question

Why not a pentose? Or a tetrose? Or a deoxy sugar? Or just some other hexose, like fructose?

Is there some chemical reason life should have settled on glucose as the standard photosynthetic output, or is it just random? It seems very suspicious that this ubiquitous molecule nicely break down into exactly 3CO2 + 3CH4, or 6CO2 + 6H2O - 6O2, or 6H2CO, when such convenient formulas are not true of the actual immediate products of carbon fixation.

Answer 1

Glucose, with the chemical formula C6H12O6, is preferred in photosynthesis over other sugars because of its versatility and efficiency as an energy source. It fulfills energy requirements for plants and is stored as starch, and during cellular respiration, it provides energy for ATP production. Its molecular structure offers an ideal balance for biological processes.

Step-by-step explanation:

The question why life has settled on glucose as the standard photosynthetic output over other sugars like pentoses, tetrose, deoxy sugars, or other hexoses like fructose is intriguing. Glucose is a six-carbon sugar with the chemical formula C6H12O6, and it plays a central role in the biochemistry of most living organisms.

During cellular respiration, glucose is broken down, releasing energy which helps in the formation of adenosine triphosphate (ATP), the primary energy currency of the cell. Moreover, the molecular structure of glucose allows for it to efficiently participate in numerous biochemical pathways and provide a balance between stability and reactivity.