The reduced electron carrier produced when NAD+ picks up high-energy electrons is:

1. An electron carrier shuttles high-energy electrons between pathways. 2. NAD+ is the oxidised form of one such carrier. 3. The sixth step in glycolysis oxidizes the sugar, extracting high-energy electrons, which are picked up by the electron carrier NAD+, producing NADH. 4. FADH2 is the reduced form of a different carrier, FAD. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 7 'Cellular Respiration', sections 7.1-7.7_