18 Questions
What is the result of the energy released by electron transfer from NADH to Q in Complex I?
Conformational changes that pump 4 protons from matrix to intermembrane space
How many protons are pumped for each 2 electrons released by NADH in Complex I?
4 protons
What is the name of the mechanism by which protons are released in the intermembrane space during the reoxidation of UQH2?
Redox loop mechanism
How many subunits are present in the hydrophilic domain of mammalian Complex I?
8 subunits
What is the correct description of the membrane domain of mammalian Complex I?
It consists of 54 trans-membrane helices and 7 subunits
What is the name of the cofactor that is not present in the enzyme Complex I?
UQ
What is the primary function of complexes I, III, and IV in the electron transport chain?
To catalyze redox reactions and pump protons across the mitochondrial membrane
What is the role of cytochrome c in the electron transport chain?
A mobile electron carrier that receives electrons from Coenzyme Q
What is the terminal electron acceptor in the electron transport chain?
Oxygen
What is the net result of the reaction catalyzed by Complex IV?
4cytc (Fe2+) + 4H+ + O2 → 4cytc (Fe3+) + 2 H2O
How many hemes are present in Complex IV: cytochrome c oxidase?
2 hemes (a and a3)
What is the function of the electron transport chain in E. coli?
To generate ATP through oxidative phosphorylation
What is the primary function of the Q cycle in Complex III?
To transfer electrons from CoQ to cytochrome c
What is the role of cytochromes in the electron transport chain?
To function as one-electron transfer agents
What is the role of CoQ in the electron transport chain?
A lipid-soluble electron carrier
What is the net result of the Q cycle in Complex III?
Two molecules of UQH2 are oxidized and two molecules of cytochrome c are reduced
What is the principal transmembrane protein in Complex III?
The b cytochrome
What is the final destination of the electrons from NADH in the electron transport chain?
Oxygen
Understand the electron transport chain mechanism, including the role of Complex I, proton pumping, and the formation of the proton gradient. Learn how NADH drives conformational changes and pumps protons from the matrix to the intermembrane space.
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