Oxidative Phosphorylation Flashcards
What prosthetic group does Complex I have?
FMN
What prosthetic group does Complex II have?
FADH2, it is succinate dehydrogenase from the CAC
What prosthetic group does complex III (ubiquinone), Q-cytochrome c oxidoreductase, have?
Heme bH and BL, Heme c1, and iron sulfur proteins
What prosthetic group does Complex IV, cytochrome c oxidase, have?
Heme a and a3, and CuA and CuB
Describe in brief the steps of the electron transport chain (ETC)
3 NADH from the CAC donates its electrons to complex I, NADH dehydrogenase; those electrons then transfer to coenzyme q; they then travel to complex III (cytochrome b, composed of bH and bL and then cytochrome c); they then travel to complex IV where they reduce oxygen to water
What inhibits the transfer of electrons from complex I to ubiquinone?
Rotenone and amytal; since ETC is inhibited, energy production is inhibited
What inhibits the transfer of electrons from complex III cyt b to cytochrome c?
antimycin
What blocks the transfer of electrons from complex IV to water?
Cyanide, azide, and CO (they all have higher affinities than oxygen)
What are the three forms of the catalytic beta subunits of the F1 component?
O (open), L (loose), and T(tight); in O form, nucleotides can bind to or be released from the beta subunit; in L form, nucleotides are trapped in the subunit; in the T form, ATP is synthesized from ADP and Pi
How many protons does it take to synthesize 1 ATP?
It changes based on the number of c-units; divide the number of subunits by 3 and that’s how many protons it takes to make 1 ATP
Remember that oxidation and phosphorylation are coupled processes
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What is the purpose of the glycerol 3-phosphate shuttle and how does it work?
It is used to transfer the electrons from NADH from the cytosol into the matrix by means of glycerol 3-phosphate since NADH cannot cross the outer mitochondrial membrane; cytoplasmic G3P-DH transfers electrons and protons from NADH to DHAP to make G3P; the G3P will then cross the outer membrane into the IMS where it will pass its e- and protons to MITOCHONDRIAL G3P-DH which will then pass them on to coenzyme Q (thus skipping complex 1); you lose energy equivalent to 1 ATP when you transport H through this process
What is the purpose and the advantage of the Malate-Aspartate shuttle?
Oxaloacetate recieves the protons and electrons from NADH via CYTOSOLIC malate dehydrogenase to make malate; malate then goes through the inner membrane to the matrix and transfers its protons and e- back onto NAD via MATRIX malate dehydrogenase, therefore no energy loss occurs because NADH is regenerated
How do adenine nucleotide and phosphate translocases work?
ADP3- is pumped through an antiporter called adenine nucleotide translocase (along with ATP4-); ATP synthase pumps protons through to create energy for phosphorylation; a symporter, phosphate translocase, pumps through phosphoric acid (H2PO4) and a proton, to donate a phosphate (Pi) and proton for ATP synthesis
What is the net yield of ATP per glucose?
You will generate 30 ATP if you go through the glycerol phosphate shuttle and 32 if you go through the aspartate-malate shuttle
