How many molecules of ATP in cell respiration?

Question

How many molecules of ATP are produced in aerobic cellular respiration? My teacher and textbook say 38, but some other sources say 36.

Answer 1

There are three steps in the process of cellular respiration: glycolysis, the Krebs cycle, and the electron transport chain.

In contrast to fermentation, in the process of cellular respiration, the pyruvic acid molecules are broken down completely to CO2 and more energy released. Note that three molecules of O2 must react with each molecule of pyruvic acid to form the three carbon dioxide molecules, and three molecules of water are also formed to “use up” the hydrogens. As mentioned above, in glycolysis, a total of four molecules of ATP are produced, but two are used up in other steps in the process. Additional ATP is produced during the Krebs Cycle and the Electron Transport Chain, resulting in a grand total of 40 ATP molecules produced from the breakdown of one molecule of glucose via cellular respiration. Since two of those are used up during glycolysis, in prokaryotes a net total of 38 molecules of ATP are produced by cellular respiration. Most prokaryotes have very simple cells which lack several types of organelles present in eukaryotes, and therefore the Krebs Cycle and the Electron Transport Chain occur in the cytoplasm and/or using chemicals embedded in the cell membrane. In contrast, eukaryotes have more complex cells with more specialized organelles to perform given functions. In eukaryotes, the Krebs Cycle and Electron Transport Chain occur within the mitochondria, and thus the pyruvic acid resulting from glycolysis must be sent into the mitochondria for these reactions to occur. However, to move one molecule of pyruvic acid (remember each molecule of glucose turns into two pyruvic acid molecules) from the cytoplasm into a mitochondrion “costs” the cell one molecule of ATP (therefore two ATPs for a whole glucose), thus a net total of 36 ATP molecules per molecule of glucose is produced in eukaryotes as compared to only two in fermentation. The overall reaction for cellular respiration is C6H12O6 + 6O2 6CO2 + 6H2O (+ energy for the cell to use for other things).

Answer 2

38

Answer 3

It can actually be 34 to 38. There is not a certain number to how much ATP can be produced but it is in that range.

Answer 4

Theoretically it is 36 ATPs total. But Actual yield it maybe lower than 36 because:

1. inner mitochondrial membrane leaky to protons, which allows these leaky protons to reenter the matrix without passing through ATP-generating channels (thus lesser ATP produce than 36). If all the protons passing through ATP-generating channels and make ATP then we would have 36 ATP total, but not all protons passing through ATP-generating channels. Therefore actual yield of ATP is lower than 36.

2. Mitochondria use proton gradients for other purposes as oppose to just making ATP. Therefore, actually yield is even lower than 36.

Answer 5

According to Tortora & Anagnostakos, as well as every text I have ever used and been taught by every professor, the net gain is 38.
C6 H12 O6 + 6O2 + 38 ADP yields 6CO2 +6H2O + 38 ATP.

Answer 6

36 are formed from each sugar molecule in the mitochondria. The other 2, well I can't remember, but there are 38 all together.

Answer 7

http://biology.clc.uc.edu/Courses/bio104/cellresp.htm

Answer 8

35.9999