Chapter 18: Electron Transport Chain/Oxidative Phosphorylation Flashcards
1
Q
FADH2 bypasses the
A
- First ETC complex
2
Q
ETC complexes floating in the inner mitochondrial matrix
A
- Complex I, II, III, and IV
3
Q
As the electrons are being passed, protons are being pumped into
A
- The intermitochondrial membrane
- Then protons move thru the ATPase to make ATP b/c of [proton] gradient
4
Q
Under aerobic conditions NADH and FADH2 generate
A
- Energy in oxidative phosphorylation by donating electrons to the ETC within the inner mitochondrial membrane
5
Q
The ETC is composed of
A
- NAD linked dehydrogenases
- Flavin linked dehydrogenases
- Cytochromes arranged in sequences
6
Q
Some NADH and FADH2 are concentrated within
A
- The mitochondrial matrix
7
Q
The NADH and FADH2 produced in glycolysis is transported
A
- Into the mitochondria via specific shuttle systems
8
Q
SDH is located
A
- In the inner membrane of mitochondria
9
Q
Oxidation reactions in the CAC and glycolysis produce
A
- NADH and FADH2
10
Q
Substrate molecules oxidized in the CAC and glycolysis produce
A
- NADH and FADH2
11
Q
Electrons from NADH and FADH2 are transported to molecular O2 to form
A
- H2O by the ETC
12
Q
As electrons are passed down the ETC
A
- They lose energy
13
Q
Energy lost by electrons as they move down the ETC can be trapped
A
- In the form of ATP when protons are pumped back across the inner mitochondrial membrane (oxidative phosphorylation)
14
Q
Energy loss along the ETC is considered
A
- An exergonic process
- The energy of the TCA is harnessed in the ETC
15
Q
Each ETC complex contains
A
- Electron carrier proteins that are water insoluble
- Oxidation/reduction centers
- Some complexes pump protons
16
Q
Complex I
A
- NAD-dehydrogenase complex
17
Q
Complex II
A
- FAD-succinate dehydrogenase complex
18
Q
Complex III
A
- Cytochrome c reductase
19
Q
Complex IV
A
- Cytochrome c oxidase
20
Q
Complex I and II converge on
A
- Coenzyme Q
21
Q
ETC pathway movement
A
- NADH > complex I > coenzyme Q > complex III > cytochrome C > complex IV > Oxygen
22
Q
As electrons move they lose energy and
A
- H+ gets pumped into the space
23
Q
Ubiquinone is a
A
- Transmembrane protein, and is small
- Not a proton pump
24
Q
Complex III is a
A
- Cytochrome-containing proton pump
25
Complex I contains
- NAD+
- FMN
- NAD-linked dehydrogenases
26
Complex I is a large complex that has
- 34 polypeptide chains
27
Complex I is both
- Proton pump
| - Electron carrier
28
Number of proteins pumped into intermembrane space by Complex I
- 4 protons
29
Complex I has a low affinity for
- Electrons which it passes to coenzyme Q
30
NADH donates its electrons from Complex I to
- The flavin mononucleotide prosthetic group, FMN forming FMNH2
31
FMNH2 of Complex I transfers its electrons to a series of
- Iron sulfur (Fe-S) clusters
| - Then passed to lipophilic ubiquinone in the lipid bilayer of the IMM
32
P/O ratio
- The amount of ATP synthesized per substrate molecule oxidized
33
As NADH is oxidized ___ protons are pumped...
- 10 protons are pumped into the imm
34
4 H+ molecules moving through the space procudes
- 1 ATP
35
When 1 mole of FADH2 is oxidized
- 1.5 moles of ATP are produced
36
As FADH is oxidezed
- 6 protons are pumped into the space
| - Complex I is bypassed
37
Complex V
- F1F0 ATPase
38
F1 of Complex V
- Water-soluble component
39
F0 of Complex V
- Lipophilic component of complex V
40
Structure of F1 component of complex V
- 5 units and a nucleotide binding site
| - ATY synthesizing moiety
41
Structure of F0 component of complex V
- 3 or 4 hydrophobic units integrated into the inner mitochondrial membrane
42
Oxidative phosphorylation and electron transport are usually
- Tightly coupled
43
Uncoupling occurs naturally in
- Mitochondria that are old or damaged
44
Electron transport without ATP synthesis results in
- Energy lost as heat (brown adipose tissue of babies and bears)
45
Artificial uncoupling agents prevent
- Formation of ATP even when electron transport occurs
46
Artificial uncoupling agents allow O2 use by
- Mitochondria in the absence of ADP
47
Uncouplers may pick up on protons and carry them
- Through the membrane into the matrix (lipid soluble)
48
Carrying of protons through the membrane disrupts
- The flow of protons through the ATPase (complex V)
49
Uncouplers of oxidative phosphorylation
- Lipid soluble, hydrophobic compounds that carry protons across the IMM
50
Uncouplers of oxidative phosphorylation dissipate
- The proton gradient
51
Uncouplers inhibit ATP formation without
- Affecting electron transport
52
Antibiotics that work via uncoupling
- Valinomycin
| - Gramicidin
53
When uncoupled, electron transport proceeds but
- No ATP is formed
54
Rotenone and amytal block
- Flavoprotein-NADH dehydrogenase complex
55
Rotenone (root extract) is used to treat
- Head lice
56
Amytal is
- An analgesic barbiturate
57
Antimycin A prevents
- The passage of electrons through the cytochrome c reductase
58
CN- and CO block
- Cytochrome oxidase
59
Inhibition of electron transport chain activity is
- Generally fatal
60
Entry of electrons from succinate bypass the step of
- Inhibition via rotenone
| - Blockage of flavoprotein-NADH dehydrogenase complex
61
The ETC is comprised of a seres of
- NAD-linked dehydrogenases
- Flavin-linked dehydrogenases
- Cytochromes organized within the IMM
62
Under aerobic conditions, NADH and FADH 2
- Donate electrons to carriers positioned in the IMM
| - Along with production of ATP
63
Electrons that enter the chain via the NAD-dependent dehydrogenase complex produce
- Approximately 2.5 molecules of ATP
64
Electrons that enter the chain via ubiquinone produce
- 1.5 molecules of ATP since complex I is bypassed
65
The mechanism by which ATP is produced from ADP and Pi as metabolic fuel is oxidized
- Oxidative phosphorylation
66
Peter Mitchell's chemiosmotic model postulates
- The electrochemical gradient formed across the IMM during electron transport is key to ATP production from ADP
67
Oxidative phosphorylation and electron transport are closely linked in that
- Electrons only pass from NADH to molecular O2 when ATP is required
68
Rotenone and amytal inhibit electron passage through
- Complex I
69
Antimycin A prevents the passage of electrons through
- Cytochrome c reductase
| - Oxidase is inhibited by CN- and CO
