Citric Acid Cycle Question?

Question

The two CO2 molecules produced from the first round of citric acid cycle originate from which compound?

Answer 1

From Oxaloacetate

1. The citric acid cycle begins with Acetyl-CoA transfering its two-carbon acetyl group to the four-carbon acceptor compound, oxaloacetate, forming citrate, a six-carbon compound.
2. The citrate then goes through a series of chemical transformations, losing first one, then a second carboxyl group as CO2.

Answer 2

1.The citric acid cycle begins with Acetyl-CoA transfering its two-carbon acetyl group to the four-carbon acceptor compound, oxaloacetate, forming citrate, a six-carbon compound.
2.The citrate then goes through a series of chemical transformations, losing first one, then a second carboxyl group as CO2.
3.Most of the energy made available by the oxidative steps of the cycle is transferred as energy-rich electrons to NAD+, forming NADH. For each acetyl group that enters the citric acid cycle, three molecules of NADH are produced.
4.Electrons are also transferred to the electron acceptor FAD, forming FADH2.
5.At the end of each cycle, the four-carbon oxaloacetate has been regenerated, and the cycle continues. Products of the first turn of the cycle are one GTP, three NADH, one FADH2, and two CO2.
6.Because two acetyl-CoA molecules are produced from each glucose molecule, two cycles are required per glucose molecule.
7.At the end of all cycles, the products are two ATP, six NADH, two FADH2, four CO2.
The first CO2 is formed from Oxalosuccinate and second from alpha ketoglutarate