Question

The TCA cycle can be used for the complete oxidation of organic carbon in respiring organisms. This is obvious by observing that one full "turn" of the cycle releases________ (one, two, three, four, six) molecules of_________ (acetyl-CoA O2, CH4, CO, CO2).

Answer 1

Answer:

2, CO2

Explanation:

Acetyl CoA (a 2 carbon compound) enters into the TCA cycle and combines with oxaloacetate (4C compound) to form a six-carbon intermediate called citrate. Further reactions include the release of one CO2 during decarboxylation of Isocitrate into alpha-Ketoglutarate and release of the second CO2 during decarboxylation of alpha-Ketoglutarate to form succinyl-CoA. In this way, the 2 carbon atoms that enter the TCA cycle in the form of acetyl CoA are released in the form of 2 molecules of CO2.