Final answer:
NAD+ and FAD are the carrier molecules that are used to transport hydrogen and electrons during cellular respiration, particularly in the Electron Transport Chain where they contribute to ATP synthesis.
Step-by-step explanation:
The hydrogen and electron carrier molecules utilized during cellular respiration are NAD+ (which becomes NADH when it is carrying electrons and hydrogen) and FAD (which becomes FADH2 when it is carrying electrons and hydrogen). These carrier molecules are essential for the transfer of energy during cellular respiration. In the final stage known as the Electron Transport Chain, NADH and FADH2 generated from earlier stages such as glycolysis and the Krebs Cycle donate high-energy electrons, which are used to create a proton gradient across the inner mitochondrial membrane and synthesize ATP via oxidative phosphorylation.