ETC & ATP Synthase Flashcards

1
Q

What are the key components of the ETC? What do they do?

A

Complex 1: Transfers electrons from NADH to ubiquinone (CoQ)
Complex 2: Transfers electrons from succinate (via FADH2) to ubiquinone
Complex 3: Transfers electrons from ubiquinol to cytochrome c
Complex 4: Transfers electrons from cytochrome c to oxygen
Ubiquinone (CoQ): Acts as an electron holder to transfer electrons from complex 1 and 2 to complex 3
Cytochrome c: Transfers electrons from Complex III to Complex IV.

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2
Q

Where does ETC take place?

A

The components of the ETC are embedded in the inner mitochondrial membrane

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3
Q

What are the benefits of having the ETC occur where it does?

A

Proton Gradient Creation (drives ATP synthesis in the ATP synthase complex)
Compartmentalization (Separates Citric acid cycle and ETC)
Efficient Electron Transfer (prevent the loss of energy as heat)

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4
Q

What is the driving force for the ETC?

A

The driving force of the ETC is the redox potential (E°’).

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5
Q

What is the pathway of the ETC?

A

-NADH donates electrons to Complex I, reducing ubiquinone (CoQ) to ubiquinol (CoQH2).
-FADH2 donates electrons to Complex II, which passes them to ubiquinone (CoQ) also reducing it
-Ubiquinol carries electrons to Complex III, where they are transferred to cytochrome c, reducing it.
-Cytochrome c carries electrons to Complex IV, where they are transferred to oxygen, reducing it to water.

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6
Q

What is the ultimate electron acceptor in the ETC?

A

Oxygen

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7
Q

What is the overall purpose of the ETC?

A

This whole process makes ATP

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8
Q

What is Proton Motive Force (PMF)?

A

The proton motive force (PMF) is the “pressure” created by the movement of protons (H⁺ ions) across the mitochondrial membrane during electron transport.

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9
Q

How Does Proton Motive Force Link Electron Transport and ATP Synthesis?

A

PMF causes protons to want to flow back inside with the gradient but must use ATP synthase.

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10
Q

What are the two main subunits of ATP synthase? What do they do?

A

F₀ Subunit (Membrane Component): Forms a channel in the membrane for H+ to move through causing rotation which causes a conformational change in F₁
F₁ Subunit (Catalytic Head): Divided into three more subunits that carry out ATP synthesis, allow ADP and inorganic phosphate (Pi) to bind, form ATP

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11
Q

What is the function of ubiquinone in the citric acid cycle?

A

It is an Electron acceptor to FADH2 and is found in the Electron Transport Chain. (Without ubiquinone accepting electrons from FADH2 and NADH the ETC would be interrupted)

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