Question

Choose the correct answers from the alternatives given :
The greatest contributor of electrons to the electron transport system is

• A. oxygen
• B. transition reaction
• C. glycolysis
• D. Krebs cycle

Answer 1

The correct option is D Krebs cycle

• Electron transport system is the transport system that is present in the mitochondrial membrane where it transports the electrons and hydronium ions from NADH and FAD through various complex of the chain.
• In chemiosmotic phosphorylation the $F_1$-$F_0$ complex is used for the synthesis of one molecule of ATP for every 2 hydronium ion that is transported through the complex from the intermembrane matrix.
  
• For each NADH transported through the chain 3 times 2 hydronium ions are released which means every molecule of NADH produces 3 molecules of ATP. For every FADH molecules passed 2 times 2 hydronium are released which means that every molecule of FADH gives 2 ATP molecules.
• Therefore when per pyruvic acid after going under kerb cycle gives 4 NADH and 1 FADH molecule that gives the cell with 12 ATP and 2 ATP molecules respectively per cycle.
• Therefore it can be said that kerb cycle is the major contributor to the electron that are provides to the ETS for the production of ATP.
• Therefore option 'Krebs cycle' is the correct answer.