Why do most of Biology textbooks, consider the energy output of cellular respiration to be 36-38 ATPs?

Question

I mean the total energy is 38 ATPs,, why do textbooks give the range of 36-38?? is there any lost energy?? I don't think so!!!

Answer 1

From wikipedia:

Biology textbooks often state that between 36-38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 32-34 from the electron transport system). Generally, 38 ATP molecules are formed from aerobic respiration. However, this maximum yield is never quite reached due to losses (leaky membranes) as well as the cost of moving pyruvate and ADP into the mitochondrial matrix.

Answer 2

1) The answer is ATP. ATP is consumed in the preparatory phase of glycolysis. 2) This should be obvious to you. Just look at your potential answers, do you honestly think humans use alcoholic fermentation? We do not produce alcohol as a waste product, you should know this. Otherwise we'd be drunk ALL the time since metabolic waste products are transported through the blood stream. Try to think. 3) I am assuming D is actually "CO2 and H2O" You should be familiar with the cellular respiration equation. 6O2 + C6H12O6 ------------> 6CO2 + 6H2O + ATP The waste products are the products of the overall reaction, or the right side of the equation. These questions are very easy and could have been easily been answered by using wikipedia.

Answer 3

Yes most science texts do consider this to be correct for how many ATP molecules are produced in the three steps of cell respiration. Think about each of the three steps involved in cellular respiration, there is some variance as with anything in science, which by the way changes everyday so get ready. Physics might be right up your alley! In oxidative phosphorylation you will have the variance dependent on the cytochrome proteins. Sometimes there are simply fewer materials present for the number of reactions required for 38 hence it produces 36. I would suggest you get a graduate biochemistry text they explain process quite well.

Answer 4

It depends on how many electrons enter the electron transport chain as NADH vs. FADH2. FADH2 provides one less electron and thus produces one less ATP.