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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
Pi
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 +Pi (+energy)
ATP [energy is not a reactant]

ADP +Pi 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 + Pi
ΔG = -30.5 kJ/mol
Many similarities and differences with Photophosphorylation in photosynthesis


This topic has connections with other BioTopics units on:-

Glycolysis ....

Krebs Cycle ...... ETC

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