Terminal Respiration Flashcards
Where is most of the NADH and FADH2 made and by what process?
Mitochondria, by citric acid cycle and beta oxidation of fatty acids
How does cytoplasmic NADH cross the mitochondrial membrane?
It can’t, instead it reduces dihydroxyacetone phosphate to produce Glycerol-3-phosphate. This passes its electrons onto FAD forming FADH2 which enters the electron transport chain, this process is called the glycerol phosphate shuttle
How many protein complexes are in the electron transport chain?
4
What happens in complex 1 after the NADH molecule is oxidised to give NAD+?
It passes the high energy e- to ubiquinone to give ubiquinol. Pumps H+ ions into the intermambrane space
What does complex to oxidise to form ubiquinol?
FADH2
What does complex 3 do?
Passes the e-‘s from ubiquinol to cytochrome C, giving two molecules of reduced cytochrome C per molecule of ubiquinol. Pumps protins into the intermembrane space
What does the 4th protein complex do?
Takes electrons from cytochrome C and passes them on to molecular O2 - Forms water
What is the name given to the turbine that can harness the energy in the proton gradient?
ATP Synthase
Where are the protons moved to by the protein complexes?
Outside the inner mitochondrial membrane
How is the energy of the proton motive force stored by ATPase?
By using the energy to synthesise ATP from ADP + Pi
Describe the two parts of ATP synthase
F0 - Rotates. Membrane bound proton conducting sub-unit - 10 subunits
F1 - Protrudes into the mitochondrial matrix and acts as the catalyst for ATP synthesis
What does the proton gradient drive?
The release of ATP and not the formation of ATP
What are the different conformations of the beta sub-unit protein on the F1 protein?
ATP
ADP + Pi
Nothing bound
How many protons are needed for each rotation of the beta subunit
3, so therefore ATP synthase can make one molecule of ATP for every H+ ion it moves across the membrane and into the matrix
What generates less ATP, FADH2 or NADH?
FADH2
For every molecule of NADH, how many protons are pumped across the membrane?
8+
Why does NADH produce more ATP than FADH2
NADH passes through carrriers 1,3 and 4 whereas FADH2 feeds in at complex 2, meaning only two of the proton releasing proteins are used
What are the last two products of terminal respiration?
CO2 and H2O
Which two processes are coupled?
Electron tranport (energy released when passing electrons along the terminal respiration system) and ATP synthesis
Give an example of a disease caused by uncoupling and why it became uncoupled?
Malignant hyperthermia. Leaky mitochondrial membrane - proton gradient cannot be generated. Proton transport occurs but there is no synthesis of ATP uncouples electron transport and the electron transport chain. Muscle cells become damaged from excessive heat build up. Used in plants to generate heat
Describe what facilitates the transport of protons from outside the inner membrane to the outside?
Thermogenin - Triggered by epinephrine
