Explain, in considerable detail, the processes through which ATP is synthesized
ID: 170785 • Letter: E
Question
Explain, in considerable detail, the processes through which ATP is synthesized via oxidative phosphorylation in the mitochondria. In your explanation, be sure to highlight (in color or with a highlighter) the following terms: NADH, electron donation, oxidation, reduction, Complex I, Complex II, Complex III, Complex IV, Complex V, ATP Synthase, Succinate Dehydrogenase, F1, FO, Cytochrome c, ubiquinone, ubiquinol, Coenzyme Q, Cytochrome c reductase, Cytochrome c oxidase, terminal electron receptor, water, proton gradient.
**MAKE SURE YOU HAVE ALL THE TERMS IN YOUR ANSWER**
Explanation / Answer
The transport of electrons through the Electron transport chain is linked with the release of free energy.The process of bysnthesising ATP from ADP and an inorganic phosphate coupled with the electron transport chain is known as oxidative phosphorylation.
The electron transport chain is a series of proteins and organic molecules found in the inner membrane of mitochondria.
Electrons are transferred from one member of Transport chain to the other in aseries of Reduction oxidation reactions.
The energy released in these reactions is used for the synthesis of ATP through proton gradient and the process is called Chemiosmosis.
Electron transport chain and the chemiosmosis together forms the Oxidative phosphorylation.
steps involved are as follows:
Delivery of electrons by NADH and FADH2 : in this process both these two get reduced donating the electrons to molecules near to the beginning of the Electron transport chain.
Electron transfer: As electrons are transferred from higher to lower energy level, they release energy which is used for driving the protons outside the matrix in to the intermembrane space.This establishes an Electro chemical gradient.
split of oxygen : at the end of the electron transport chain , electrons are transferred to molecular oxygen to form water.
Gradient driven synthesis of ATP: as the protons flow through a gradient and passes through matrix, they pass through an enzyme called ATP synthase which helps in the synthesis of ATP.
Electron transport chain is organised into four complexes labeled from I to IV. NADH is good at donating electrons thus initiating the proton gradient across the membrane., thus underging oxidation reaction.
FADH2 is not a good donar of electrons so it transfers so it transfers them to Complex II through complex I.
Both complex I. and complex II transfers the electrons to a small carrier called Ubiquinone .
Ubiquinone undergoes reduction to form Ubiquinol.It travels through the membrane and delivers the electrons to complex III .
These electrons are again transferred to a carrier called cytochrome C and from this electrons are carried to complex IV. At the complex IV electrons are passed to oxygen molecule to form water molecule.
complex V is responsible for ATP synthesis.there are 3 sites where ATP is synthesised. they are1. oxidation of FMNH2 by coenzyme Q
2. oxidation of cytochrome b by cytochrome c1.
3. cytochrome oxidase reaction. It takes place at complex IV. the cytochrome oxidase helps in the formation of water molecule.
coenzyme Q is also called Ubiquinone found in the living systems.It acts as an electron carrier.
Cytochrome C is a small protein found in ETC. it is the central part of the ETC with a Redox potential.
Succinate Dehydrogenase is an enzyme found in the inner mitochondrial membrane.It is a flavoprotein with FAD as the coenzyme. It can accept two hydrogen atoms from succinate and can form FADH2.
Terminal electron receptor receives the electrons from another molecule. here in Electron transport chain Oxygen acts as a terminal electron acceptor by accepting electrons to form water molecule.Oxidation reaction is taking place here.
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