QUESTION 44 Consider a 10-carbon fatty acid. How many electrons will be carried
ID: 211318 • Letter: Q
Question
QUESTION 44 Consider a 10-carbon fatty acid. How many electrons will be carried to the electron transport chain as a result of the complete oxidation of this molecule (fatty acid oxidation + Krebs cycle)? QUESTION 45 Only glucose, through the generation of pyruvate and the subsequent oxidation of pyruvate to acetyl-CoA can be used to fuel the Krebs cycle. True False QUESTION 46 Consider a 10-carbon fatty acid. How many FADH2 molecules will be produced during the complete oxidation of this molecule (fatty acid oxidation + Krebs cycle)?Explanation / Answer
44. In the first stage of fatty acid oxidation, fatty acids undergo oxidative removal of successive two-carbon units in the form of acetyl-CoA, starting from the carboxyl end of the fatty acyl chain. Therefore, fatty acid oxidation of 10 carbon fatty acid generates 5 acetyl CoA molecules, 4 NADH and 4 FADH2 molecules. From one molecule of acetyl-CoA, 3 NADH molecules and one FADH2 molecule are formed by Krebs cycle.
Total NADH formed = 4 (from fatty acid oxidation) + 15 (5 acetyl-CoA generates 15 NADH during Krebs cycle) = 19
Total FADH2 formed = 4 (from fatty acid oxidation) + 5 (5 acetyl-CoA generates 5 FADH2 during Krebs cycle) = 9
One NADH and FADH2 donates 2 electrons during its oxidation. Then total number of electrons are transported to the ETC will be
(19*2) + (9*2) = 38 + 18 = 56
45. Only Glucose, through the generation of pyruvate and the subsequent oxidation of pyruvate to acetyl-coA can be used to fuel the Krebs cycle---this statement is false, as fatty acid oxidation also generates acetyl-CoA which enters into Krebs cycle and ETC to generate ATP (the fuel).
46. Complete oxidation of 10 carbon fatty acid generates in total nine FADH2 molecules.