Fates of Pyruvate – Key Vocabulary

Nine vocabulary flashcards summarizing essential terms related to pyruvate metabolism, fermentation, and metabolic effects discussed in the lecture.

Fermentation

ATP-yielding metabolic process that operates without O₂ and maintains the cellular NAD⁺/NADH balance, e.g., lactic acid or ethanol production.

Lactic Acid Fermentation

Anaerobic pathway; pyruvate accepts electrons from NADH and is reduced to lactate while regenerating NAD+ via lactate dehydrogenase

Ethanol (Alcohol) Fermentation

Anaerobic reduction of pyruvate into ethanol and CO2; pyruvate decarboxylase converts pyruvate into acetaldehyde, then alcohol dehydrogenase converts this into ethanol, regenerating NAD+

Pasteur Effect

the rate and total glucose consumption under anaerobic conditions is greater than aerobic conditions because ATP yield from glycolysis is much smaller than oxidation to CO2 (2 vs 30-38/ glucose); when O2 is present, yeast, etc will send pyruvate to become acetyl-CoA → citric acid cycle → ETS for ATP production, thus consuming less glucose

Warburg Effect

tumor cells favor high-rate glycolysis with lactate production even in the presence of O₂, lowering pH; assisted by HIF-1α (transcription factor that increases glucose consumption); basis for PET imaging.

Cori Cycle

Metabolic loop in which anaerobic muscle exports lactate to the liver, where it is converted back to glucose that returns to the muscle for energy.

Cori cycle step 1

muscle breaks down glucose for energy, creating pyruvate; when O2 is present, pyruvate goes to the CAC; when no O2, pyruvate stays in the cytosol and is converted into lactic acid

Cori cycle step 2

lactic acid is exported into the blood and taken up by the liver to be converted back into pyruvate in hepatocytes for gluconeogenesis; the liver releases that glucose back into the blood, where muscle can take it up again