NAD +molecule
Explanation:
Krebs cycle and electron transport chain are important steps in cellular respiration.
In the Krebs cycle, there is a need of NAD+ molecule which is then in Krebs cycle reduced to form a NADH2 molecule.
NADH2 is also an energy currency. It , giving electron in electron transport chain and return to Krebs cycle as NAD+.
Now in the Krebs cycle, it is ready to take electrons again.
