ATP yield from

Note The.se P/O ratios of 2.5 and 1.5 for mitochondrial oxidation of NADH and [FADHg] are consen.sns values. Because diey may not reflect actual values and because these ratios may change depending on metabolic conditions, the.se estimates of ATP yield from glucose oxidation are approximate. 

When calculating ATP yields from p oxidation, you have to be careful to notice whether you start with the fatty acid or with the fatty acyl-... 

You only have to look at the ATP yield from the TCA cycle, 12 of them per molecule of acetyl-CoA, to know that oxidative phosphorylation must be important. That s where all the electrons from NADH and FADH2 go after they re made by the TCA cycle. 

The current estimate for the number of ATPs made per 2 electrons is actually about 2.5. This is because of the uncertainties in the number of protons pumped out at each electron transfer step. This affects ATP yields from glucose (30 instead of 36), so be sure you ask your professor which to use. 

A. The ATP yield from glucose metabolism via oxidative phosphorylation is approximately 34—36 ATP molecules per glucose molecule (Table 7-1). 

CoA (see Table 17-1). A similar calculation can be made for the ATP yield from oxidation of each of the amino acids (Chapter 18). Aerobic oxidative pathways that result in electron transfer to 02 accompanied by oxidative phosphorylation therefore account for the vast majority of the ATP produced in catabolism, so the regulation of ATP production by oxidative phosphorylation to match the cell s fluctuating needs for ATP is absolutely essential. 

TABLE 19-5 ATP Yield from Complete Oxidation of Glucose... 

This compares with only two ATPs as the net ATP yield from glycolysis. Thus an extra four ATPs per glucose are required to reverse glycolysis. 

Table 1. Calculation of the ATP yield from the complete oxidation of palmitate ...

The oxidation of palmitic acid to acetyl-CoA requires seven /3-oxidation cycles, each producing 1 FADH2 molecule (2 ATP) and 1 NADH molecule (3 ATP). This is 35 ATP for the seven cycles. Because each palmitic acid molecule requires an equivalent of 2 ATP molecules to become activated [Equation (19.5)], the net ATP yield is 33. Because each acetyl-CoA yields 12 ATP via the Krebs cycle (Chapter 18), the total ATP yield from the oxidation of one palmitic acid molecule is 12(8) + 33 = 129. 

Table 20.2 Net ATP Yields from the Catabolism of Amino Acids...

As a comparison, note that 32 moles of ATP can be obtained from the complete oxidation of one mole of glucose but glucose contains 6, rather than 18, carbon atoms. Three glucose molecules contain 18 carbon atoms, and a more interesting comparison is the ATP yield from the oxidation of three glucose molecules, which is 3 X 32 = 96 ATP for the same number of carbon atoms. The yield of ATP from the oxidation of the lipid is still higher than that from the carbohydrate, even for the same number of carbon atoms. The reason is that a fatty acid is all hydrocarbon except for the carboxyl group that is, it exists in a... 

Mathematical Calculate the net ATP yield from the complete processing of a saturated fatty acid containing 17 carbons. Consider the P-oxidation steps, processing of acetyl-CoA through the citric acid cycle, and electron transport. 

Mathematical Calculate the net ATP yield from oleic acid (18 1 A ). Hint Remember the step that bypasses acyl-CoA dehydrogenase. 

Mathematical Calculate the net ATP yield from linoleic acid (18 2 A 4 ). For this calculation, assume that the loss of an NADPH is the same as the loss of an NADH. 

These answers are readily obtained if one remembers the ATP yields from the various parts of glycolysis and remembers that (1) cytoplasmic NADH yields only 1.5 ATP,... 

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