Electron Transport System and O2 — NEET Biology
✅ Asked in NEET 2025In the electron transport system, the terminal electron acceptor is: NEET 2025
In the electron transport system, the terminal electron acceptor is: NEET 2025
Which statement is incorrect? NEET 2018
Cytochromes are found in: NEET 2015/ AIPMT 2015
Answer & NCERT explanation
Correct answer: D — Oxygen
In electron transport system, oxygen serves as the terminal electron acceptor. Electrons flow through complexes I, III, and IV, and finally oxygen accepts electrons and combines with protons to form water. Cytochrome oxidase is the enzyme that catalyzes this final step, but oxygen itself is the acceptor.
Read more NCERT concept on the PYQ
The following steps in the respiratory process are to release and utilise the energy stored in NADH+H+ and FADH2. This is accomplished when they are oxidised through the electron transport system and the electrons are passed on to O2 resulting in the formation of H2O. The metabolic pathway through which the electron passes from one carrier to another, is called the electron transport system (ETS) and it is present in the inner mitochondrial membrane. Electrons from NADH
The electron transport system (ETS) in the inner mitochondrial membrane transfers electrons from NADH and FADH2 to oxygen, forming water. This is the final step of aerobic respiration where energy is released. Students often confuse ETS with the Calvin cycle or forget that O2 is the final electron acceptor, not an intermediate one. Many wrongly think water formation happens during photosynthesis respiration. Remember: ETS requires oxygen as the terminal electron acceptor, electrons pass through carrier proteins in the inner mitochondrial membrane, and this process generates maximum ATP. The coupling of electron transfer with ATP synthesis is what NTA emphasizes.
What does NCERT say about following steps respiratory process?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.