Cellular Respiration Questions!

If NAD+ is being reduced, it is gained electrons. Hydrogen ions are positively charged. If the NAD+ plus molecule becomes reduced by two electrons, one electron is going to make it in NAD (no charge) and a second electron is going to make it NAD-. Now that it is negatively charged, it will attract a hydrogen ion (H+), making it into NADH.

NAD+ NAD NAD- NADH

You mean the carbonyl becomes a carboxyl? When succinyl-CoA is converted to succinate, it is undergoing a chemical reaction through the hydrolytic release of coenzyme A by succinyl-CoA synthetase. The release of CoA from succinyl releases a relatively large amount of energy, leaving succinyl molecule highly charged and free to attract free hydroxyl molecules floating in the medium where the kreb cycle is occuring. Recall that water is made up of H2O; in the presence of charged molecules, some water molecules in the vicinity of the reaction chemically convert to -OH (hydroxyl molecules) - which is where the extra oxygen came from. My advice is don't look to into it - they won't ask you why on a test.

The reaction: GDP + Orthophosphate (Pi) + Succinyl-CoA <=> GTP + Succinate + CoA