Which metabolite is produced by anaerobic glycolysis?

• A. Pyruvate
• B. Lactate
• C. Acetyl-CoA
• D. Oxaloacetate

Answer: (B)

Lactate is produced during anaerobic glycolysis. When oxygen is scarce, pyruvate from glycolysis cannot be efficiently shuttled into the mitochondria to be converted into acetyl-CoA for the TCA cycle. To keep glycolysis functioning and regenerate the essential NAD+, cells convert pyruvate into lactate using lactate dehydrogenase, which reoxidizes NADH back to NAD+. This allows glycolysis to continue producing a small amount of ATP despite the lack of oxygen.

Pyruvate itself is the end product of glycolysis, but its fate depends on oxygen: with oxygen available, pyruvate is converted to acetyl-CoA and enters the TCA cycle; acetyl-CoA is a downstream product of that aerobic pathway. Oxaloacetate is a TCA cycle intermediate that can be formed in other pathways, but it is not the immediate product of anaerobic glycolysis.