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Oxidation (3 definitions)	Oxidative phosphorylation	OP takes place alongside electron transport chain in
Combination with oxygen	Phosphorylation is a process - addition of phosphate	inner membrane of
Removal of hydrogen	Part of aerobic respiration	mitochondria inside
Loss of electrons (clue: OIL RIG)	Other parts of respiration which provide reactants ... glycolysis, link reaction & Krebs/TCA/citric acid cycle	cells of
Opposite of oxidation is ... reduction		Eukaryotes (animals, plants, fungi +)

Oxidative phosphorylation -
Reactants and reactions

Reduced NAD (Nicotinamide adenine dinucleotide)	H⁺ (protons) and electrons (e^-) from Reduced NAD/FAD enter Electron Transport Chain		ADP (Adenosine diphosphate)
Sometimes written as NADH, or NADH/H⁺ [also reduced FAD flavin adenine dinucleotide FADH - similar but less energy]	Electrons are passed along the ETC & stay in the membrane: 4 subunits (complexes I-IV)	H⁺ are pumped/ deposited at the other side of the membrane- in the inter-membrane space	P_i is inorganic phosphate [not P alone] Adenosine is adenine + ribose - as in RNA
A coenzyme - absorbs energy from breakdown of molecules in other reactions	Electrons pass from compound to compound in ETC (redox reactions) losing energy at each stage	H⁺ builds up so there is a concentration gradient between inside and outside of mitochondrion - *chemiosmosis*	This energy from H⁺ moving down its concentration gradient is used to phosphorylate ADP (combine ADP and Pi)
Provide reducing power: H⁺ & e^- (proton and electron donation)	Electrons' energy is used to pump H⁺ across the membrane	H⁺ passes though ATP synthase back into centre of mitochondrion	ADP +P_i (+energy) ATP [energy is not a reactant] ADP +P_i ATP
And are oxidised in the process	Electrons and protons are passed to oxygen: final electron/proton acceptor 4H⁺ + 4e^- + O₂ 2H₂O		Oxidative phosphorylation
and recycled … RH₂ + NAD⁺ NADH + H⁺ + R	The reason why we breathe in air containing oxygen!		ATP (adenosine triphosphate) is the energy currency of cells ATP + H₂O ADP + P_i ΔG° = -30.5 kJ/mol

Many similarities and differences with Photophosphorylation in photosynthesis
Electron transport chain

Electron transport chain

This topic has connections with other BioTopics units on:-

Glycolysis ....

Krebs Cycle ...... ETC

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