True about electron transpo chain
Current Concept, Energetics of ATP Synthesis The free energy released by electron transpo through complex I to IV must be conserved in a form that ATP synthase can perform energy coupling. The energy of electron transfer is used to drive protons out of the matrix by the complexes I, III and IV that are proton pumps. The proton gradient thus created is maintained across the inner mitochondrial membrane till electrons are transferred to oxygen to form water. The electrochemical potential of this gradient is used to synthesize ATP. According to the estimated free energy of synthesis, it was presumed that around 3 protons are required per ATP synthesized. Hence when one NADH transfers its electrons to oxygen, 10 protons are pumped out. This would account for the synthesis of approximately 3 ATP. Similarly the Fig. 19.12. Complex IV (cytochrome oxidase) of respiratory chain pumping of 6 protons, accounting for 2 molecules of ATP. However, Peter Hinkle recently proved that the actual energy production is less, because there is always leakage of protons. This results in harnessing of energy required for the production of 2.5 ATP from NADH and 1.5 ATP from FADH2. The synthesis of one ATP molecule is driven by the flow of 3 protons through the ATP synthase (see below). When NADH is oxidized, 10 hydrogen ions (protons) are pumped out (Fig. 19.13). According to recent findings, one NADH may generate only 2.5 ATP; and one FADH2 may generate only 1.5 ATP. So, one molecule of glucose will generate only 32 ATPs. The traditional values and the new values are compared in Table 19.4. (Please note that there is no change in the values of ATP generation by substrate-level phosphorylation). Energy efficiency of glucose oxidation giving 32 molecules of ATP and palmitate giving 106 molecules of ATP is given as 34% and 33% respectivelyRef: MN Chatterjea Textbook of Medical Biochemistry, 6th edition, page no: 230
FADH gives 2 ATP
Entry point of NADH is at complex II
NADH gives 3 ATP
FADH gives 3 ATP
Respiratory chain