Which energy pathway involves producing cellular energy without oxygen, using glycolysis to yield 2 ATP per glucose and produce lactic acid?

Which energy pathway involves producing cellular energy without oxygen, using glycolysis to yield 2 ATP per glucose and produce lactic acid?

• A. Aerobic respiration
• B. Anaerobic respiration
• C. Oxidative phosphorylation
• D. Krebs cycle

Answer: (B)

When oxygen isn’t available, cells rely on glycolysis followed by fermentation to meet energy needs. Glycolysis makes a net 2 ATP per glucose and yields pyruvate. In the absence of oxygen, pyruvate is converted to lactate to regenerate NAD+, allowing glycolysis to continue. This produces 2 ATP per glucose and lactate (lactic acid) as a byproduct, which is the hallmark of anaerobic energy production. In contrast, aerobic pathways require oxygen and involve mitochondria (Krebs cycle and oxidative phosphorylation) to make much more ATP.

When oxygen isn’t available, cells rely on glycolysis followed by fermentation to meet energy needs. Glycolysis makes a net 2 ATP per glucose and yields pyruvate. In the absence of oxygen, pyruvate is converted to lactate to regenerate NAD+, allowing glycolysis to continue. This produces 2 ATP per glucose and lactate (lactic acid) as a byproduct, which is the hallmark of anaerobic energy production. In contrast, aerobic pathways require oxygen and involve mitochondria (Krebs cycle and oxidative phosphorylation) to make much more ATP.