Question

Choose the correct answers from the alternatives given :
Most of the ATP made during cellular respiration is generated by

• A. direct synthesis of ATP by the Krebs cycle
• B. substrate-level phosphorylation
• C. oxidative phosphorylation
• D. glycolysis

Answer 1

The correct option is C oxidative phosphorylation

• Oxidation phosphorylation is the process where the electron acceptor such as NADH and FADH release their H ions and the ions and the electrons are tranported through various complexs of electron transport system.
• NADH gives electrons which pass through 5 complexs of the ETS and FADH pass through 4 complexs of the ETS
• These electron at the end of the transport system react with oxygen and form a molecule of water.
• Where the proton which is released by the complexs of the ETS during the transport of electrons are used in formation of ATP.
• one molecule of NADH forms 3 molecules of ATP and one molecule of FADH forms 2 molecules of ATP
• So after one cycle of kerb 4 molecules of NADH are released and one molecule of FADH which results in formation of 12 ATP and 2 ATP respectively. Thus generating 14 ATP for each pyruvic acid.
• Therefore the amount of the maximum generated ATP in cellular respiration is done by oxidative phosphorylation.
• Therefore the answer option 'oxidative phosphorylation' is correct.