Exam 3.2 Flashcards
1
Q
What is an anapleuotic reaction?
A
replenishing CAC cycle intermediates that have been extracted for biosynthesis
2
Q
Is oxaloacetate considered a catalyst?
A
Yes
3
Q
Anapleurotic reactions off set the loss of _________ taken for biosynthesis
A
intermediates
4
Q
Decreased [catalysts] = INCREASED/DECREASED rate?
A
decreased
5
Q
If an intermediate of CAC is withdrawn what happens to the rate of the CAC?
A
slows
6
Q
what is the most important anapleurotic reaction?
A
pyruvate –> oxaloacetate
7
Q
what enzyme catalyzes the most important anapleurotic reaction?
A
pyruvate carboxylase
8
Q
what cofactor is involved in the most important anapleurotic reaction?
A
biotin
9
Q
What molecule activates the most important anapleurotic reaction?
A
acetyl coA
10
Q
what are the 2 domains of pyruvate carboxylase?
A
- BC (biotin carboxylase)
- CT (carboxytransferase)
11
Q
what is the P/O ratio for NADH?
A
2.5 (NADH comes from matrix)
1.5 (using G3P pathway)
12
Q
Which Complex is NOT involved in succinate oxidation?
A
Complex I
13
Q
What is the P/O ratio fro NADH generated in the cytosol?
A
1.5 (FAD dependent)
2.5 (malate/aspartate)
14
Q
Why are the 2 issues involving NADH in the cytosol?
A
- cannot cross the inner membrane
- can only enter the RETC via Complex I which is on the matrix side
15
Q
How many ATP are generated and H+ translocated using the FADH dependent method?
A
1.5 ATP
6 H+
16
Q
How many ATP a generated and H+ translocated using the malate/aspartate dependent method?
A
2.5 ATP
10 H+
17
Q
Including the actions of respiratory electron transport and F1F0 ATPase, how many ATPs will be generated as a result of converting one pyruvate to an acetyl coA
A
2.5
18
Q
T/F almost all oxidoreductases require a cofactor to function
A
True
19
Q
NADH is an obligate _______ donor
A
hydride (2e-)
20
Q
What is the only Complex involving NADH?
A
Complex I
21
Q
Flavins are __e- acceptors and ___e- donors
A
2e- acceptors
1e- donor
22
Q
What are the 4 obligate 2e- (hydride) donors?
A
- NADH (Complex I)
- succinate (Complex II)
- glycerol-3-P
- fatty acetyl coA
23
Q
What allows flavins to be obligate 1e- donors?
A
semiquinone intermediate
24
Q
Fe/S clusters are obligate ___e- donors/acceptors
A
1e-
25
What are the 2 oxidative states of 2Fe/2S and 4Fe/4S?
Ferric/ferrous?
Fe II (ferrous)
Fe III (ferric)
26
Rieske Fe/S clusters are ________ to reduce and ________ to oxidize
easier
harder
27
What coenzyme are highly hydrophobic?
UQ
28
What coenzyme freely moves in the inner membrane?
UQ
29
UQ is a obligate ___e- donor/acceptor?
1e-
30
What coenzyme shuttles e- between donors/acceptors?
UQ
31
What is the Q-cycle?
as UQ is reduced H+ is pumped into the IMS
32
Hemes are prosthetic groups for __________
cytochromes
33
Hemes are obligate ___e- donor/acceptor
1e-
34
What is special about cytochrome a3?
it is penta so the 6th spot is open for O2 binding
35
What is the only complex with Cu?
Complex IV
36
What are the 2 types of Cu and what do they do?
CuA: electron transfer
CuB: assists cytochrome a3 in O2 reduction
37
Rieske 4Fe/4S is easier to reduce, what is its delta G?
positive (easier to reduce)
38
How is partial reduction of O2 prevented?
keeping cofactors near each other
39
What is another name from Complex I?
NADH ubiquinone oxidoreductase
40
What is another name for Complex II?
succinate ubiquinone oxidoreductase
41
What is another name for Complex III?
ubiquinol cytochrome c oxidoreductase
42
What is another name for Complex IV?
cytochrome c oxidase
43
What is the largest Complex?
Complex I
44
In complex I, where are all the cofactors found?
soluble portion (points into matrix)
45
How many H+ are translocated from Complex I?
4
46
What are 2 inhibitors of Complex I?
Rotenone
Amytal
47
How does Rotenone and Amytal inhibit Complex I?
blocks UQ binding site
48
What happens to the RETC when Complex I inhibitors are present?
NADH accumulates = lactate accumulation (lactate DH) = CAC inhibited
49
Exposure to rotenone will lead to an increase in __________ production
lactate
50
What cofactor does Complex II have that doesn't participate in e- transfer and we are not sure why its there
heme b
51
How many H+ are translocated at Complex II?
none
52
What is an inhibitor of Complex II?
thenoyl trifluoroacetone carboxin
TTC
53
Complex III has 2 sets of 11 subunits, the side oriented towards the IMS is Q__ and the side oriented near the matrix is Q____
Q P (IMS) (positive)
Q N (Matrix) (negative)
54
How many H+ are translocated at Complex III?
4
55
What cycle is used also in Complex III to translocated H+?
Q cycle
56
What are 3 inhibitors of Complex III?
1. myxothiazol
2. antimycin A
3. stigmatellin
57
How does myxothiazol inhibit Complex III?
binds to Q P site preventing e- transfer from UQH2 to Rieske Fe/S or Cyt. bL
58
How does Antimycin A inhibit Complex III?
binds to Q N site preventing e- transfer from Cyt. bH to UQ
59
How does stigmatellin inhibit Complex III?
binds to Q P site and forms a hydrogen bond disrupting its bond with UQH2 and binding to a His residue (reducing potential of Rieske Fe/S)
60
In Complex IV, what does subunit I do?
O2 reduction
61
What cofactors are in Complex IV's subunit I?
Cyt. a
Cyt. a3
Cu B
62
In Complex IV, what does subunit II do?
site of Cyt. c binding
63
What cofactor is in Complex IV's subunit II?
Cu A
64
In Complex IV, what does subunit III do?
hydrophobic channels to direct O2 to subunit I
65
What cofactor is in Complex IV's subunit III?
none
66
How many H+ are translocated across Complex IV?
2 (per e- pair)
67
What are the 3 channels of Complex IV?
K channel
D channel
H channel
68
Complex IV's K channel's H+ comes from _______
Cu B
69
Complex IV's D channel's H+ comes from _______
Cyt. a3
70
Complex IV's H channel's H+ comes from _______
matrix
71
Which Complex IV channel is vectoral?
H channel (matrix to IMS physically)
72
I am an electron transport complex, I have no Rieske Fe/S, no hemes and no FAD.
Complex I
73
I am an electron transport complex, I have Fe/S and hemes but no flavins.
Complex III
74
There is a __________ gradient and a ___________ gradient across the inner membrane
concentration
charge
75
RETC's goal is to pump H+ into ________ for ATPase to make ATP
IMS
76
The pH in the IMS is _______ than the pH in the matrix
lower (more H+)
77
The delta G pushing against the gradient is POSITIVE OR NEGATIVE?
positive
78
The delta G at the end of RETC is POSITIVE OR NEGATIVE?
negative
79
Who created the chemiosmotic hypothesis?
peter mitchell
80
What is the chemiosmotic hypotheisis?
Free E (-G) delivered from H+ passage across the membrane with the gradient provides the driving force for ADP phosphorylation
81
What is 5 pieces of evidence to support the chemiosmotic hypothesis?
1. intact membrane
2. inpermiable inner membrane
3. e- transport = H+ transport out of matrix
4. increasing acidity outside = increase ATP production
5. compounds that increase permiability prevent ATP synthesis
82
What is an uncoupling agent?
able to cross the mitochondrial inner membrane (in protonated state), the deprotonates once across (INCREASE PERMIABILITY)
83
What are 4 examples of uncoupling agents?
1. 2,4-dinitrophenol
2. Fluorocarbonyl cyanide phenylhydrazine
3. Dicoumarol
4. Thermogenin
84
The coupling agent, ___________, is expressed in brown fat of mitochondria
Thermogenin
85
What is brown fat?
uses proton gradient to generate heat to protect CNS and organs (babies)
86
T/F Introduction of a K+ channel in the mitochondria inner membrane will disrupt ATP synthesis by F1F0.
True
87
T/F introduction of a K+ channel in the mitochondria inner membrane will result in lactate accumulation.
False (uncoupling agents are not inhibitors so they are no inhibiting the e- flow they are only affecting "downstream" ATP synthesis)
88
What couples the H+ generated by RET and ADP phosphorylation?
F1F0 ATPase
89
Where is F1F0 ATPase located?
F0 - inner membrane
F1 - matrix
90
What is F1 refered to as?
the generator
91
What are the subunits of F1?
3 alpha
3 beta
1 gamma
1 delta
1 epsilon
92
What does the alpha subunit do of F1?
binds ATP but DOES NOT catalyze
93
the alpha subunit of F1 provides an ______ residue to the beta subunit
Arginine
94
What are the 3 binding options for the beta subunit of F1?
AMP PNP (ATP)
ADP + Pi
empty
95
When (AMP PNP) ATP is bound to the beta subunit of F1, is the KD high or low?
low (high association)
96
The center of the alpha/beta orange of F1 is very _________ made of ___________
hydrophobic
3 alpha helices
97
In the presence of ATP and the absence of F0, the gamma subunit rotates in the ____________ direction
counter clockwise
98
Which subunit of F1F0 ATPase is in the matrix? F1 or F0?
F1
99
What is a name for F0?
turbine
100
How many alpha helices is the c ring of F0 made of?
12
101
c ring of F0 has Asp61 on each subunit, what is special about the last one?
It is partially off the subunit because of helical unwinding which allows H+ to bind and be dropped off in the matrix
102
subunit a of F0 has a _______ residue
Arg 210
103
What subunit of F0 has a half channel for H+?
a subunit
104
Which complex does dicoumarol bind to?
none
105
Which complexes activity is inhibited by dicoumarol?
F1F0 ATPase
106
Consider an F1F0 ATPase who has 9 c subunits, how many H+ across the mitochondria inner membrane will result in one full revolution of the c ring?
9
107
Consider a F1F0 ATPase who has 9 c subunits. Passage of how many H+ across the mitochondria inner membrane will result in one full revolution of the gamma subunit?
9
108
How many ATP are made for every gamma revolution?
3
109
What is the purpose of the Complexes in the RETC?
build a high concentration of H+ in the IMS
110
H+ in the IMS enters ATPase where?
F0 (a subunit)
111
What structurally distinguishes heme a, b, and c
a: long tail
b: normal
c: S-protein
112
T/F: under standard conditions, malate oxidation by NAD+ is energetically favored
false
113
T/F: almost all hemes found in the ETC are hexacoordinate
true
114
T/F: In the context of the citric acid cycle, oxaloacetate can be viewed as a catalyst
true
115
What electron transport complex contains a Reiske Fe/S center?
complex III
116
What electron transport complexes do not contain hemes?
complex I
117
Which about stigmatellin is true?
a. It binds to QP site
b. Interrupts Q cycle
c. Prevents conformational change in Complex III
d. All are true
d. All are true
118
What is the order of electron transfer in Complex I?
NADH, FMN, 2Fe/S, 4Fe/S, UQ
119
In Complex I, what would happen if conformational change is not possible?
no H+ transfer but e- would still happen
120
What would happen if UQ binding is affected in Complex I?
no e- transfer and no H+ transfer stopping all other complexes after I
121
Would someone with no e- transfer or with e- would have more pyruvate DH kinase activity/lactate accumulation?
the one with NO e- transfer because NADH would accumulate and Pyruvate DH would have to deal with it ramping up glycolysis
PDK is activates by NADH
122
The RETC moves towards the more _____ direction
positive (reduced)
123
Why are the cofactors in the specific orders they’re in in the RETC?
reduction potential and obligate donor/acceptors
124
How does CN affect succinate DH?
decreases succinate DH (COMPLEX II) activity b/c it affects O2 ability to be a final e- acceptor which will back up the cycle
125
How does CN affect pyruvate DH?
DECREASES pyruvate DH activity b/c it affects O2 ability to be a final e- acceptor which will ACCUMULATE NADH WHICH IS AN INHIBITOR FOR IR
126
How does CN affect glycogen phosphorylase?
increase because RETC is backed up and glycogen needs to be broken down to up regulate glycolysis to take care of accumulated NADH
127
T/F: in the absence of F0, F1 catalyzes ATP synthesis
false (catalyzes ATP hydrolysis)
128
T/F: The identity of the fatty acyl-CoA dehydrogenase used in -oxidation depends upon the carbon chain length of the fatty acyl-CoA substrate.
true
129
Carboxin is an inhibitor for which complex?
Complex II (inhibits succinate)
130
What is the visual difference between NADH and FAD?
NADH has 1 N ring
FAD has 2 N rings
131
What is the visual difference between FAD and FMN?
FAD has a bunch of stuff at the bottom
FMN looks just like it without the clutter at the bottom
132
What is visual difference between CuA and CuB?
CuA is more complicated looking (makes a square)
133
How does stigmatellin affect Rieske Fe/S clusters?
affects the reduction potential
