Respiratory Chain Flashcards
Oxidation- reduction proteins are located within the
mitocondrial membrane
This respiratory chain serves to break up the 52 kcal/mole available from the flow of ___from NADH to O2 into approximately three equal amounts.
2 electrons
This respiratory chain serves to break up the 52 kcal/mole available from the flow of 2 electrons from NADH to O2
the majority of this energy is used to
form atp
The rate of respiration is controlled by the availability of ___
ADP
Advantages of a membrane-bound respiratory chain chain
(1) Kinetics: Not limited by the rate of diffusion; no mobile carrier needed.
(2) Stability of intermediates: reduced fuel will be converted to energy stored in an electrochemical gradient. For a gradient you need two compartments. The membrane provides such a boundary.
Flavins:___donor/acceptor
two-electron
Flavins have a ___ addition
1,4
NADH dehydrogenase contains tightly bound
FMN
Succ. Dehyd. contains covalently bound ___
FAD
Iron-Sulfur Centers: Accept e-1s from
Flavins and Q
iron sulfate centers may have ___ irons per
center
2-4
Iron-Sulfur Centers have how many electron donor/acceptors?
They may have 2-4 irons per
center, but they are _one-electron donor/acceptors. _
Acidification of iron sulfar centers leads to →
H2S gas
Ubiquinone: ___-electron donor/acceptor
two
ubiquinone Functions as an electron ___.
buffer
Ubiquinone has ___ additon
1,6
Hemes: ___-electron donor/acceptors
one
The heme is covalently attached to two ____ side chains in cytochromes c and c1.
cysteine
The iron atom of the heme group in cytochrome c coordinates to a
methionine and a histidine side chain in addition to the 4 porphyrin-ring nitrogens.
Copper Centers: one-electron donor/acceptors in
cytochrome oxidase
Copper center A contains ___ Cu
two
what forms the forms the O2 binding site at the end of the Respiratory Chain?
- Copper center B
- the heme iron of Cyt a3
in cytochrome oxidase
what is in cytosohome oxidase?
CuA, CuB, Cyt a, Cyt a3
path of electron flow in cytochrome oxidase?
to CuA -> cytocrhome a -> cytochrome 3 -> cuB
The participation of two copper centers and two heme irons in cytochrome oxidase may be required in order to (2)
- rapidly deliver 4e- to O2
- avoid production of H2O2 and superoxides.
For efficient flow, components should be arranged in order of ___
INCREASING ELECTRON AFFINITY
order of the components of the respiratory chain?
Nad -> Q -> b -> C -> a
___ contains three catalytic sites for ATP synthesis
F1
____ is a hydrophobic complex that transverses the membrane and carries protons from one site to the other.
Fo
the endergonic synthesis of ATP is obligatorily coupled to the ___
exergonic redox reactions
the reverse is also true
Oxidative Phosphorylation
____ → NAD+ + 3 ATP + 4 H2O
NADH + H+ + 1/2 O2 + 3 ADP + 3 Pi
NADH + H+ + 1/2 O2 + 3 ADP + 3 Pi → ___
NAD+ + 3 ATP + 4 H2O
______ functions as a common
intermediate linking Oxidatian on to Phosphorylation.
electrochemical gradient
___ is coupled to ATP synthesis.
The rate of respiration is controlled by the availability of ADP
Oxygen consumption
ADP consumed/0OCnsumped =?
atp formed per pair of electrons
An explanation for respiratory control:?
Back pressure from the electrochemical gradient stops the flow of electrons down the respiratory chain at those points where proton transport is coupled to a redox reaction unless the protons are carried back into the matrix space
1 electron donors/acceptors
- iron sulfur center
- hemes
- copper centers
2 electron donor/acceptor
- flavins: fmn, fmnh2, fad
- ubiquinone
the e- carriers along the respiratory chain are arranged in order of increasing affinity for electron
this is important for the ____
efficiency of extracting useful energy.
____ is an excess mobile e- carrier between the early dehydrogenases and the later part of the respiratory chain.
ubiquinone
_____of cytochrome oxidase is the only heme group in the respiratory chain that binds O2
cytochrome a3
cytochrome oxidase is able to provide rapid delivery of ___ to the terminal acceptor, O2.
4 e-
how is the two part structure of the ATP synthase complex oriented on the inner mitochondrial membrane.
Fo is in the inside of the membrane
F1 is in the matrix
The limitation placed on_____by the chemisosmotic gradient is termed respiratory control.
electron transport
If the electrochemical gradient is destroyed by damaging the membranes, respiratory control is
abolished and electron transport can run freely.
