Why do human muscle cells produce lactate during anaerobic respiration while yeast cells produce an alcohol?
Specifically due to the enzyme in muscles (lactate dehydrogenase) that breaks down glucose into lactate. Lactate is then transported to the liver which is reduced to pyruvate and put into the gluconeogensis cycle and new glucose is produced to continue the cycle. Alcohol is a toxin and its break down yields acetaldehyde which is responsible for the hangover feeling the next morning.
