Anatomy of the Heart. Your heart is located under your ribcage in the center of your chest between your right and left lungs. Its muscular walls beat, or contract, pumping blood to all parts of your body. The size of your heart can vary depending on your age, size, and the condition of your heart.
In anaerobic respiration, NADH loses its electrons to other molecules in the process of fermentation for the purpose of regenerating the NAD+ needed to continue oxidizing organic molecules to produce ATP by substrate-level phosphorylation.
In an aerobic process of cellular respiration, Stage 2 is when pyruvate and NADH are used to make ATP but in an anaerobic process of cellular respiration, a pyruvate is converted to either ethanol and carbon dioxide or lactate through fermentation.