6: Respiratory Chain Flashcards
The organization of key electron transport complexes along the respiratory chain and which of these serve as ‘coupling sites’ to drive oxidative phosphorylation.
Organization of complexes in inner mitochondrial membrane:
Complex 1 = NADH dehydrogenase
Complex 2 = Succinate dehydrogynase
Complex 3 = bc 1 complex
Complex 4 = cytochrome oxidase
NADH dehydrogenase contains tightly bound FMN. Succ. Dehyd. contains covalently bound FAD. Flavins: two-electron donor/acceptor + 2H+, 1,4-addition.
We pump protons @ complex 1, 3, 4!
That the e- carriers along the respiratory chain are arranged in order of ______ affinity for electron(s), and that this is important for the efficiency of _____ useful energy (i.e., increasing ___).
That the e- carriers along the respiratory chain are arranged in order of increasing affinity for electron(s), and that this is important for the efficiency of extracting useful energy (i.e., increasing Eo’).
Oxygen has the highest affinity for the electron.
When an electron passes through a large E#o drop, the electron is passing from an oxidation/reduction center of lower affinity to one with a much greater affinity. This stabilization of the electron is an exergonic process that could be coupled to the endergonic generation of an electrochemical gradient.
oxidative phosphorylation net result = 3 ATP
The identity of five different classes of electron carriers, where they are found in the respiratory chain complexes, and whether they are 1 or 2 electron donor/acceptors.
Flavins: two-electron donor/acceptor + 2H+, 1,4-addition. NADH dehydrogenase contains tightly bound FMN. Succ. Dehyd. contains covalently bound FAD.
Ubiquinone: two-electron donor/acceptor + 2H+
Hemes: one-electron donor/acceptors (Fe3+ + e- ↔ Fe2+). Cytochromes have heme groups.
Copper Centers: one-electron donor/acceptors in cytochrome oxidase (Complex IV)
The unique role of ______ as an excess mobile e- carrier between the early dehydrogenases and the later part of the respiratory chain.
The unique role of ubiquinone (Q) as an excess mobile e- carrier between the early dehydrogenases and the later part of the respiratory chain.
That cytochrome ____ of cytochrome oxidase is the only heme group in the respiratory chain that binds O2 (and why this is a good thing).
That cytochrome a3 of cytochrome oxidase is the only heme group in the respiratory chain that binds O2 (and why this is a good thing).
How cytochrome oxidase is able to provide rapid delivery of ___ e- to the terminal acceptor, O2.
How cytochrome oxidase is able to provide rapid delivery of 4 e- to the terminal acceptor, O2.
Describe the two-part structure of the ATP synthase complex, and how it is oriented on the inner mitochondrial membrane.
ATP synthase = FoF1
F1 contains three catalytic sites for ATP synthesis. It is connected to Fo by a central stalk (or rotor) and an external stalk (stator).
Fo is a hydrophobic complex that transverses the membrane and carries protons from one site to the other.
What is Respiratory Control, and what causes it.
Respiratory control = slowing down ATP synthesis when you do not need to make ATP anymore. The rate of respiration is controlled by the availability of ADP (Respiratory Control).
See pg. 121
