Step 1, Glycolysis- Outside of the mitochondria, this step breaks down glucose into pyruvic acid molecules to continue the process. 2 ATP is used to break down glucose into 2 acids, and because glucose has 6 carbons, both acids have 3 carbons now, and covalent bonds are broken (Catabolic). 4 ADP gets turned into 4 ATP, 2 NADH+ into 2 NADH (Endergonic), and there is a net gain of 2 ATP Increases entropy