electron transport chain ETC and oxidative phosphorylation .pptx

1. Electron Transport Chain ETC
and
Oxidative phosphorylation

2. What is an Electron Transport chain?
The electron transport chain (ETC) is a sequence of redox reactions that take place in a cell’s inner
membrane of the mitochondria (or plasma membrane in prokaryotes).
The ETC is essential in the process of oxidative phosphorylation, which is the method by which
cells make ATP by transferring electrons using the ETC and subsequently production of ATP by
ATP synthase.
How ETC produce ATP?
During the ETC, electrons are transmitted down a succession of protein complexes (complex I, II,
III, and IV) and mobile electron carriers (such as coenzyme Q and cytochrome c) in a sequence of
redox processes, causing a proton gradient across the membrane. This proton gradient is
subsequently utilized to fuel the production of ATP by ATP synthase, which uses the gradient’s
energy to convert ADP and inorganic phosphate into ATP.
The ETC is a highly controlled mechanism that needs the coordinated activity of numerous
proteins, coenzymes, and prosthetic groups. Any interruption in this process can result in the
accumulation of reactive oxygen species (ROS) and oxidative stress, which can damage cellular
components and contribute to the development of a range of illnesses.
Electron Transport Chain (ETC) & Oxidative phosphorylation

3. https://www.youtube.com/watch?v=zJNx1DDqIVo
Watch this
Electron Transport Chain (ETC) & Oxidative phosphorylation

5. Components of Electron transport chain
The electron transport chain (ETC) is made up of protein complexes and electron carriers that are found
in the inner mitochondrial membrane of eukaryotic cells or the plasma membrane of prokaryotic cells.
Complex I (NADH dehydrogenase): This complex takes in electrons from NADH and transfers them
to ubiquinone (Q) while pumping protons across the inner mitochondrial membrane.
Complex II (succinate dehydrogenase): This complex receives electrons from FADH2 (which is
created during the citric acid cycle) and transfers them to ubiquinone, but it does not pump protons.
Ubiquinone (coenzyme Q): Ubiquinone is a mobile electron carrier which accepts electrons from
complexes I and II and transfers them to complex III.
Complex III (cytochrome bc1 complex): Complex III accepts electrons from ubiquinone and transfers
them to cytochrome c while pumping protons.
Cytochrome c: This mobile electron carrier accepts electrons from complex III and passes them to
complex IV.
Complex IV (cytochrome c oxidase): This complex accepts electrons from cytochrome c and transfers
them to oxygen, the final electron acceptor. The reduction of oxygen to water also contributes to the
proton gradient.
The exchange of electrons between these components initiates a sequence of redox reactions that result
in a proton gradient across the inner mitochondrial membrane. The ATP synthase enzyme uses this
gradient to generate ATP from ADP and inorganic phosphate.
Electron Transport Chain (ETC) & Oxidative phosphorylation

6. Substrate-level phosphorylation is when a nucleoside diphosphate
(ADP or GDP) is phosphorylated by a substrate to produce a
nucleoside triphosphate (ATP or GTP).
Oxidative phosphorylation is the phosphorylation of ADP to ATP
using the free energy produced from redox reactions in the electron
transport chain.