How many molecules of NADH + H⁺ are produced during the breakdown...

We have till now seen that glucose has been broken down to release CO₂ and eight molecules of NADH + H⁺ ; two of FADH2 have been synthesised besides just two molecules of ATP in TCA cycle. You may be wondering why we have been discussing respiration at all – neither O₂ has come into the picture nor the promised large number of ATP has yet been synthesised. Also what is the role of the NADH + H⁺ and FADH2 that is synthesised? Let us now understand the role of O₂ in respiration and how ATP is synthesised.