Before pyruvate enters the citric acid cycle, it is decarboxylated, oxidized, and combined with coenzyme A, forming acetyl-CoA, carbon dioxide, and one molecule of:

Explanation

Before entering the citric acid cycle, pyruvate undergoes a preparatory step where it is decarboxylated and oxidized, resulting in the formation of acetyl-CoA, carbon dioxide, and NADH. NADH is created when NAD+ is reduced, capturing electrons released during the oxidation of pyruvate. FADH2, ATP, and ADP are not products of this specific conversion; FADH2 is generated in later stages of the citric acid cycle, while ATP and ADP are involved in energy transfer processes elsewhere in cellular respiration.