Electron Transport Chain Flashcards

1
Q

TCA Cycle and cancer:
The loss of ____ _____ prevents the repair of double stranded DNA breaks, and the cell accumulates mutations. ____ is the substrate to FH. ____ accumulates and acts as a oncometabolite by blocking HIF Prolyl hydroxylase and other alpha-ketoglutarate dependent dioxygenases

A

Fumarate hydratase (FH)
Fumarate
Fumarate

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2
Q

The electron transport chain conveys electrons from ___ and ____ to molecular oxygen to make water. The energy from this electron transfer is used to create a ___ ____ across the inner mitochondrial membrane. _____ ____ uses the energy of this proton gradient to add inorganic phosphate to ____, creating ATP.

A

NADH and FAD2H
Proton gradient
ATP synthase
ADP

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3
Q

ATP synthase allows protons to come back into the ___ ____ powering ATP synthesis

A

Mitochondrial matrix

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4
Q

When the electron chain reduces NADH, the electrons are Carried from complex I through _____ __ to complex III, then through ____ __ to complex IV.

A

Coenzyme Q
cytochrome C

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5
Q

Complex ____ reduces molecular oxygen to water

A

IV

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6
Q

When NADH is used, ____ protons are pumped from the matrix to the intermembrane space, creating the ____ ___

A

10
Proton gradient

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7
Q

When FAD2H is used, complex ___ performs the oxidation, not Complex I for NADH. Other than that difference, the path is the same

A

II

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8
Q

When FAD2H is used, ___ protons are pumped across the inner mitochondrial membrane

A

6

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9
Q

Complex II uses ____ ____ to oxidize FAD2H

A

Succinate dehydrogenase

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10
Q

Complex I uses ___ ___ to oxidize NADH to NAD+

A

NADH dehydrogenase

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11
Q

Acyl CoA dehydrogenase in Fatty acid beta-oxidation and glycerol 3 phosphate dehydrogenase can also use ____ and transfer electrons to ____ __

A

FAD
coenzyme Q

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12
Q

Complex I pumps ___ protons to the intermembrane space

A

4

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13
Q

Coenzyme Q is lipid soluble and exists in the inner mitochondrial membrane. It can except one electron to form ____ which is its half reduced form, and is the main source of oxidative stress.! it’s fully reduced form is ____.

A

Semiquinone
Dihydroquinol

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14
Q

Reduced Coenzyme Q (QH2) drops ___ protons off in the intermembrane space as it is oxidized by _____. Then electrons pass directly to ____ through iron-sulfur protein subunits

A

2
Complex III
Cytochrome C

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15
Q

The oxidation of NADH and the reduction of O2 through complexes I, III, and IV pump ___ protons to the intermembrane space

A

10

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16
Q

Complex IV uses ____ ___ to oxidize 2 protons and 1/2 O2 to form water

A

Cytochrome oxidase

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17
Q

The 6th step of TCA cycle using ___ ___ to oxidize Succinate to Fumarate is part of the ____ ___ ___ in Complex II, involved in creating the proton gradient

A

Succinate dehydrogenase
Electron transport chain

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18
Q

Because complex II (Succinate dehydrogenase) does not span the ___ ___ ___, no protons are pumped into the intermembrane space when it transfers electrons to Coenzyme Q

A

Inner mitochondrial membrane

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19
Q

Incomplete reduction of oxygen forms ___ ___. Semiquinone interacts with O2, transferring a single electron and forming _____.

A

Free radicals
Superoxide (O2-)

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20
Q

The ___ ___ is a form of oxidative stress

A

Hydroxyl radical

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21
Q

According to the ____ ____ of ATP synthesis, the pumping of protons across the mitochondrial membrane generates a proton motive force

A

Chemiosmotic theory

22
Q

Protons flow through 12 ___ ____ in the F0 portion of ATP synthase. This rotates the ___ portion which catalyzes ___ synthesis

A

C subunits
F1
ATP

23
Q

Translocation of 12 protons completes one ____ of the rotor, generating ___ ATP

24
Q

There are 3 ____ pairs which are catalytic sites in F1

A

Alpha-beta

25
F1 catalytic sites join ADP with inorganic ____ to create ATP
Phosphate
26
10 protons pumped by NADH 4 protons per ATP 10/4 = _____ ATP per 1 NADH
2.5
27
6 protons per FAD2H 4 protons per ATP 6/4 = ____ ATP per 1 FAD2H
1.5
28
A lot of energy is released during the electron transport chain as ___
Heat
29
_____ and ____ are drugs that chemically uncouples oxidative phosphorylation
Dinitrophenol Salicylate
30
____ and ____ are drugs that block Complex I (NADH dehydrogenase)
Rotenone Amytal
31
____ is a drug that blocks complex II (Succinate dehydrogenase)
Malonate
32
______ is a drug that blocks complex III
Antimycin A (antibiotic)
33
____, ____, and ____ are drugs that block complex IV (cytochrome C oxidase)
Cyanide, carbon monoxide, and Azide
34
_____ is a drug that blocks ATP synthase (complex V)
Oligomycin (antibiotic)
35
Summary of drug effects on electron transport chain:
36
Disrupting the electrochemical potential without synthesizing ATP ____ the electron transport chain. Normally the rate of electron transport chain is tightly coupled to the rate of ATP synthesis
Uncouples
37
____ ____ is a normal response to cold in infants where they uncouple the electron transport chain from ATP synthase in order to create heat because they can’t shiver
Adaptive thermogenesis
38
_____ uncoupling is when toxins can transport protons from the intermembrane space to the matrix. This is unregulated and bad
Chemical
39
____ uncoupling is when damage to membranes equalizes proton concentration between the intermembrane space and matrix. This is unregulated and bad
Mechanical
40
_____ is a proton channel called thermogenin. It is activated by norepinephrine which allows fat to be utilized for heat, independently of ATP consumption
UCP1
41
______ is a chemical uncoupler. It is a lipid soluble molecule with a pKa near neutral. Therefore it can bind a proton and diffuse across the inner membrane releasing the proton in the ____
Dinitrophenol Matrix
42
Mechanical uncoupling due to peroxidation of ____ lipids by reactive oxygen species. The mitochondria will swell due to an influx of water. Proton leaking makes it impossible to generate the ____ ____
Membrane Concentration gradient
43
In healthy cells, the ATP synthase inhibitor ____ causes a decrease in the oxygen consumption rate by ______ (cytochrome C oxidase). The addition of uncoupler ___ restores oxygen consumption
Oligomycin Complex IV FCCP
44
Addition of the complex I inhibitor ____ and the complex III inhibitor ____, deprives cytochrome C oxidase (complex IV) of substrate and causes ____ in oxygen consumption rate
Rotenone Antimycin A Decrease
45
The inner mitochondrial membrane is only permeable to:
O2, CO2, NH3, and H2O
46
The matrix side is ____ charged compared to the intermembrane space side. The pH is ____ in the matrix than in the intermembrane space (proton concentration is lower in the matrix)
Negatively Higher
47
____ ____ is an inhibitor of nucleotide transport in and out of the mitochondria
Bongkrekic acid
48
Mitochondrial dysfunction can lead to the formation of the ____ ____ ____ ___ (MPTP), a large complex between ANT and VDAC. This pore causes _____ of mitochondrial membrane, and disrupts the proton gradient
Mitochondrial permeability transition pore Depolarization
49
______ regulates the formation of MPTP. A high electrochemical gradient inhibits it’s formation. ____, _____, and ____ promote MPTP formation
Cyclophilin D Calcium Inorganic phosphate ROS
50
Activation of MPTP can lead to ____ or ____ (non programmed cell death).
Apoptosis Necrosis
51
_____ is released through the MPTP and signals for cell death. Cytochrome C forms a complex with ____ which activates a cascade of caspase proteases
Cytochrome C Apaf-1