What is equivalent to half a glucose molecule that has been oxidized to the extent of losing two electrons as hydrogen atoms?

Explanation

Half a glucose molecule corresponds to a three-carbon unit. In glycolysis, when this unit loses two electrons as hydrogen atoms, it reduces NAD⁺ to NADH. The molecule that directly undergoes this oxidation is glyceraldehyde-3-phosphate. Pyruvate is formed later, and dihydroxyacetone phosphate is not directly oxidized. Therefore, the correct equivalent of half a glucose losing two electrons is glyceraldehyde-3-phosphate.