Question

If one triose phosphate completely oxidized inside a prokaryotic cell than the gain of ATP of energy equal to?
A. 5 ATP
B. 4 ATP
C. 20 ATP
D. 19 ATP

Answer 1

Hint: Troise phosphate is sugar and for its complete oxidation, it undergoes various steps like glycolysis, gateway reaction, and the TCA cycle.
ATP is produced either through oxidative phosphorylation in the ETC or directly in the above-mentioned pathways.

Complete answer: When one triose phosphate sugar is completely oxidized inside a prokaryotic cell then the net gain of Total ATP energy is the sum of the ATP's produced at different cycles at different steps.
The net gain of ATP is a total of 20ATP's these 20ATP are divided at different steps of the different cycles.
As in the glycolysis step 2 ATP and 1NADH are produces that are again followed with the 1NADH in the gateway reaction and 1GTP, 3NADH, and $1FADH_2$ in the TCA cycle(tricarboxylic acid cycle).

\[1FAD{H_2} = 2ATP,{\text{ }}1GTP = 1ATP,1NADH = 3ATP.\]

So when we add up all these we get the 20 ATP's in total.

Additional information: The ATP molecule reserve energy in the form of a high energy phosphate bond joining the terminal phosphate group to the rest of the molecule.
In this form, energy can be reserved at one location, then moved from one part of the cell to another, where it can be released to function other biochemical reactions.

Hence, the correct option is (C), 20 ATP.

Note: The generation of ATP from the $FADH_2$, NADP, GTP occurs in the ETC or the electron transport chain, these are not produced directly inside the cycles wherein these products are made.