Final answer:
The molecule used to carry electrons in the cell is NADH. Along with its role in electron transport, other carriers such as FADH₂ and Coenzyme Q also participate in shuttling electrons to drive ATP synthesis.option 2 is correct .
Step-by-step explanation:
The nucleotide-containing molecule commonly used to carry electrons in the cell is NADH. Nicotinamide adenine dinucleotide (NAD+) can accept electrons from an organic molecule and get reduced to NADH, which then serves as an electron carrier. This process is an essential part of the electron transport chain in cellular respiration, where NADH donates its electrons to help form a proton gradient that ultimately drives the synthesis of ATP through a protein complex called ATP synthase.
In addition to NADH, other electron carriers include FADH₂ and Coenzyme Q (ubiquinone). FADH₂ is also involved in carrying electrons directly to the electron transport chain, but since these electrons bypass the first complex, fewer ATP molecules are made from FADH₂. Coenzyme Q is a mobile electron carrier that moves freely in the hydrophobic environment within the mitochondrial inner membrane, shuttling electrons from both NADH and FADH₂ to later stages of the electron transport chain.