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1. The impossibility of zero-calorie beer (6) Ethanol that we consume is oxidize

ID: 591300 • Letter: 1

Question

1. The impossibility of zero-calorie beer (6) Ethanol that we consume is oxidized to acetate in the liver, which is then converted to acetyl-CoA and further metabolized to 2 CO2 Determine how many molecules of ATP (or equivalent) are produced from the complete oxidation of one molecule of ethanol to 2 CO2 Assume that 1 ATP molecule is consumed to form acetyl-CoA from acetate and CoA Reactions for the metabolism of ethanol to acetate are in the textbook, p.342. Use P:O ratios of 2.5 ATP per NADH and 1.5 ATP per for QH2 Show your reasoning!

Explanation / Answer

In the presence of enzymes alcohol dehydrogenase and acetaldehyde dehydrogenase, ethanol is converted into acetaldehyde and acetate respectively and both use NAD+ and oxidant.

Therefore in the cytosol, 2 NAD are produced.

Depending on the movement of electrons into the mitochondria, 1.5 ATP are produced per NADH, so conversion of ethanol into acetate 3 ATP are produced.

During conversion of ethanol into acetyl-CoA, further produced 2CO2 and 1 ATP molecule.

Complete oxidation of acetyl-CoA in the TCA cycle produced 10 ATP molecules in which

3 NADH produced 2.5 ATP each;

1 FADH2 produced 1.5 ;

1 GTP

Ethanol oxidation thus produced= 11 ATP or

                                                    =11 ATP/2 carbons

                                                        = 5.5 ATP/ carbon