Class 11 · Respiration in Plants

Electron Transport System and O2 — NEET Biology

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📖 NCERT Source

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

NCERT Biology · Class 11 · Chapter 12 · Paragraph 35
How NTA Uses This Concept

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.

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This paragraph was tested 3 times in NEET.

Q1 of 3NEET 2025

In the electron transport system, the terminal electron acceptor is: NEET 2025

Q2 of 3NEET 2018

Which statement is incorrect? NEET 2018

Q3 of 3NEET 2015

Cytochromes are found in: NEET 2015/ AIPMT 2015

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