Which molecule carries high-energy electrons produced during glycolysis?

• A. FADH2
• B. NAD+
• C. NADH
• D. ADP

Answer: (C)

The main concept here is how energy-rich electrons are captured and carried during glycolysis. In glycolysis, glucose is oxidized and its electrons are transferred to NAD+, reducing it to NADH. This NADH then acts as the shuttle for those high-energy electrons to the mitochondrial electron transport chain, where their energy is used to generate ATP. That makes NADH the best answer, because it is the molecule that actually carries the electrons produced in glycolysis. FADH2 is another electron carrier but is produced later in other pathways like the citric acid cycle. NAD+ is the oxidized form that accepts electrons, not the carrier itself, and ADP is the substrate that becomes ATP, not an electron carrier.