Final answer:
Pyruvic acid is converted to acetyl CoA during cellular respiration after the removal of a carbon dioxide molecule and two hydrogen ions. This conversion takes place in the presence of oxygen in the mitochondria and leads to the formation of acetyl CoA, which enters the citric acid cycle.
Step-by-step explanation:
During cellular respiration, pyruvic acid is converted to acetyl CoA following the loss of one carbon dioxide molecule and two hydrogen ions. The correct answer to the question is c. Acetyl CoA.
In the presence of oxygen, a three-carbon pyruvate molecule undergoes a transformation in the mitochondrial matrix. This transformation is catalyzed by the enzyme pyruvate dehydrogenase, which leads to the oxidative decarboxylation of pyruvate into a two-carbon acetyl coenzyme A (acetyl CoA) molecule, releasing one molecule of carbon dioxide and transferring electrons to form NADH. Subsequently, acetyl CoA enters the citric acid cycle (also known as the Krebs cycle or TCA cycle), where it combines with a four-carbon molecule, oxaloacetate, to form a six-carbon molecule called citric acid.