Question

Number of ATP molecules produced from 1 glucose molecule in aerobic respiration.
A. 38
B. 32
C. 30
D. 28

Answer 1

Hint: Aerobic respiration involves the breakdown of glucose molecules into energy in the presence of oxygen. It is also known as the cellular respiration that takes place in the cytosol of the cell.. The energy produced is in turn involved in the production of ATP(adenosine triphosphate). ATP is known as the energy currency of the cell because it provides energy to the cell for its working.

Complete step by step answer: The conversion of glucose to ATP occurs in a stepwise manner. The ATP molecules can also be produced from NADPH (nicotinamide adenine dinucleotide phosphate) and $FAD{H}_2$ (flavin adenine dinucleotide).These molecules will be sent to the electron transport chain and then converted into ATP molecules. The conversion of glucose takes place in the following steps:
In the first stage glycolysis occurs where glucose is converted into two pyruvate molecules. In this reaction 2 ATP and 2 NADH molecules are produced.
Even though 4 ATPs are produced in glycolysis 2 ATPs are required during the glycolysis. Hence the net gain of ATPs during the glycolysis is 2.
The next stage two molecules of pyruvate are converted into Acetyl-CoA, 2 NADH are produced.
IN Kreb’s cycle 2 ATP, 6 NADH and 2 $FAD{H}_2$ are produced.
Now these NADH and $FAD{H}_2$ molecules are sent into the electron transport chain for conversion.
4 hydrogen ions are required for 1 ATP.
1 NADH molecule produces 10 hydrogen ions which produces 2.5ATP.
Then from glycolysis there are 2 NADH molecules . they will give 3ATP.
From conversion of pyruvate to Acetyl CoA will give 2 NADH then it gives 5 ATPs
The 6 $FAD{H}_2$ molecules from Krebs cycle give 15 ATP.
1 $FAD{H}_2$ molecule produces 6 hydrogen ions which gives 1.5 ATP.
2 $FAD{H}_2$ molecules from Kreb cycle gives 3 ATP molecules
In total 30 ATP molecules are produced per glucose.
So, the correct answer is option (C) 30.

Note: - The actual ATPs produced by one molecule of glucose are 32 but 2 molecules of ATP are used during the initial stages of glycolysis. So if we calculate the net ATP produced at last we will get 30 molecules of ATP per one glucose molecule.