Question

1.) Which of the following uses its length and flexibility to facilitate transfer of an acetyl group in pyruvate dehydrogenase?

a) FAD

b) lipoamide

c) coenzyme A

d) NAD

2.) Approximately how many ATP molecules per glucose are synthesized by anaerobic metabolism in eukaryotes?

a) 2

b) 4

c) 32

d) 300

Answer 1

1. The pyruvate dehydrogenase enzyme complex has three subunits out of which the second subunit contains a lipoamide that helps in the transfer of an acetyl group onto a coenzyme A. Hence the correct answer is: b. Lipoamide. The FAD and NADH act in the third subunit of the enzyme complex restoring the native state of the enzyme and the coenzyme A is the substrate in this reaction.

2. In anaerobic metabolism, only the glycolysis pathway occurs and during this pathway 2 net ATP are produced and 2 NADH are produced per glucose molecule. But the 2 NADH produced are reused during the conversion of pyruvate to either lactate or ethanol in eukaryotes and hence the total amount of ATP produced is 2. Hence the correct answer is: a. 2.

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