When coenzyme a enters the krebs cycle with a 2-carbon molecule, what happens?

a. an atp molecule is produced.
b. nadh is produced to go to the electron transport chain.
c. a carbon dioxide molecule is released.
d. a citric acid molecule is produced.

The correct answer is D.

Acetyl CoA is condensed with a four carbon intermediate , oxaloacetate, to form citrate.  The citrate then goes through a series of chemical transformations , losing two carboxyl groups as CO2.

The Krebs  cycle serves two  main purposes namely.

1. to increase the cell's ATP producing potential by generating reduced electron carriers such as NADH and reduced ubiquinone.

2. to provide the cell with a variety of metabolic precursors which are one FADH and four NADH molecules

cellular respiration oxidizes food into energy in the form of atps.

glycolysis (6 c hexose) > 2x atps are used > 6c hexose biphosphate > 2 x 3c triphosphate >

2 x 3c pyruvate (2x nadh produced from nad) and (4x atp produced)

pyruvate actively pumped mitochondrial matrix.