Review of Related Diseases (RRD) 1 Practice Exam

Under low oxygen, cells rely more on glycolysis to make ATP because oxidative phosphorylation needs oxygen to function. Glycolysis happens in the cytosol and can proceed without oxygen, providing ATP, though less efficiently. To keep glycolysis going, cells must regenerate NAD+, often by converting pyruvate to lactate, which allows glycolysis to continue even when oxygen is scarce. Hypoxia also activates HIF-1, which increases glucose transporters and glycolytic enzymes, further boosting glycolysis as an adaptive response. This is why hypoxia forces cells to rely on glycolysis for energy production. The other statements aren’t accurate: lack of oxygen does not inhibit glycolysis, glycolysis does not stop entirely in hypoxia, and oxidative phosphorylation does not become more active when oxygen is scarce.