In the preparatory reaction that involves movement of pyruvic acid into mitochondria TAKES PLACE IN THE MITOCHONDRIAL MATRIX WHERE THE PYRUVIC ACID IS OXIDIZED AND CARBON DIOXIDE IS RELEASED. In this reaction, NAD+ is also reduced. The end products of a preparatory reaction are 4 NADH molecules, 4 hydrogen ions, 2 carbon dioxide molecules, 2 ATP molecules and 2 acetyl CoA molecules.