Microbial Metabolism Practice Test 2026 – Complete Exam Prep Resource

Microbes rely on a small set of molecules that store and transfer energy. ATP is the direct energy currency its hydrolysis powers many cellular processes. NADH and FADH2 are electron carriers that store reducing energy and deliver it to the electron transport chain to drive ATP synthesis. Pyruvate, by contrast, is a central metabolic intermediate—an entry point for fermentation or respiration and a source of energy only after it’s converted through downstream pathways. It isn’t used to transfer energy in the same direct way as ATP, NADH, or FADH2. That’s why pyruvate is not considered a high-energy molecule in this context.