Lecture 11.5.14-11.7.14 (Exam #4) Flashcards
1
Q
Redox Reaction is also known as
A
oxidation reduction reactions
2
Q
Redox Reactions
A
reactions that are concerned with the transfer of electrons between species
3
Q
Oxidation (4)
A
loss electrons
loss hydride
loss of energy
exothermic
4
Q
Reduction (4)
A
gain electrons
gain hydride
gain of energy
endothermic
5
Q
Oxidation reactions are_______ while reduction reactions are ________
A
spontaneous; nonspontaneous
6
Q
Acids_____protons. Acid______electrons.
A
donate/accept
7
Q
Bases____protons.Bases____electrons.
A
accept/donate
8
Q
What does SHE stand for?
A
Standard Hydrogen Electrode
9
Q
What is the purpose of SHE?
A
an electrode that is the basis for the thermodynamic scale of oxidation-reduction potentials
10
Q
The abbreviation for SHE is
A
H+/H2
11
Q
Examples of mobile carriers of electrons (2)
A
Cytochrome C; Q membrane
12
Q
Examples of prosthetic groups (3)
A
FAD; heme; iron sulfur clusters
13
Q
Example of redox couples
A
NADH/NAD+
14
Q
Reduction potential
A
Eo
ability to reduce (how well one substance reduces another)
electrochemical concept
15
Q
A + reduction potential is spontaneous or non-spontaneous?
A
spontaneous
16
Q
What happens if electrons flow toward/away from SHE
A
towards from SHE= negative voltage (nonspontaneous)
away from SHE= positive voltage (spontaneous)
17
Q
The reducing agent is ___
A
reductant that loses electrons and is oxidized
18
Q
The oxidizing agent is_____
A
oxidant that gains electrons and is reduced
19
Q
A - reduction potential has a ___affinity for electrons than SHE. It is an electron___.
A
lower;donor
reductant
20
Q
Reductant
A
the donor of electrons than can reduce any compound with a less negative voltage
21
Q
A + reduction potential has a ____affinity for electrons than SHE. It is an electron___.
A
higher; acceptor
oxidant
22
Q
Oxidant
A
acceptor of electrons that can oxidize any compound with a less positive voltage
23
Q
In the ETC, NADH ____ electrons eventually to____.
A
donates; O2
24
Q
The inner membrane matrix is the______side of the mitochondria.
A
negative
25
The cytoplasmic membrane matrix is the____side of the mitochondria.
positive
26
NAD+ is coenzyme or prosthetic group.
coenzyme
27
FAD is a coenzyme or prosthetic group.
prosthetic group
28
delta E0
standard reduction potential difference between 2 half reactions
29
equation for delta E0 (measured in volts)
delta E0=E0 (acceptor/oxidant)-E0 (donor/reductant)
30
How do electrons flow in the ETC?
down their gradient
31
Electrons move from a carrier that is a ______towards carriers that are_____.
reductant(high r.p)/oxidants(low r.p)
32
How is the ETC a very efficient process?
Stepwise recovery of energy from oxidation of NADH and FADH2 during respiration to generate ATP
33
The ETC transfers electrons to different protein complexes, while ____ are pumped to make a gradient.
hydrogen ions
34
What are the complexes found in the ETC? (5)
```
NADH reductase (complex 1)
Succinate Dehydrogenase (complex 2)
Cytochrome-c oxidoreductase (complex 3)
Cytochrome-c oxidase (complex 4)
ATP Synthase (complex 5)
```
35
Mobile Carriers in the ETC
Ubiquinone (Q) & Cytochrome C
36
oxidative phosphorylation occurs where?
inner mitochondrial membrane
37
The driving force of oxidative phosphorylation is?
the electron transfer of NADH or FADH2 relative to that of O2
38
What happens due to the electron flow through the complexes?
Leads to the transport of protons across the inner mitochondrial membrane
39
How many ATPs per NADH
~3
40
How many ATPs per FADH2
~2
41
Q-Cycle
bring 2es to 1e transfer at a time
42
Order of electron transfer (7steps)
NADH-Complex 1- Q-Complex 3-Cytochrome C-Complex 4- O2
43
____is a mobile carrier of electrons to Complex 3
CoQ
44
Q pool
population of Q's in the inner mitochondrial membrane
45
cytochrome (4)
any protein with an iron heme prosthetic group, can be Fe3 or Fe2
participate in one electron transfer
absorb light at different wavelengths
transfer only 1 electron at a time
46
Flavoproteins
proteins that contain either FAD or FMN as a prosthetic group
can participate in either 1 or 2 electron transport
47
Fe-S can only transfer ____ electrons and also involve ___ and ___. Why?
one; Fe2 and Fe3
| Because of the close proximity of the iron atoms
48
Does Complex 2 transport protons?
NO
49
Which complexes transfer electrons to CoQ
Complex 1 & 2
50
Cells use ___ to break down glucose and store its energy in molecules of ATP
oxygen
51
When can the energy in glucose be used by the cells
once it is stored as ATP
52
The synthesis of ATP is coupled by?
oxidation of NADH and the reduction of O2
53
How is the positive free energy of ATP overcome?
the large negative free energy associated with proton flow down its gradient
54
Why can't electrons be transferred directly from NADH to O2?
Because this allows the pumping of protons across the inner membrane that creates a gradient that eventually is responsible for the production of ATP
55
Electron Carriers of the ETC (5)
```
NADH-Q reductase
Q
cytochrome reductase
cytochrome oxidase
cytochrome c
```
56
Copper participates in ____ electron transfer
1
57
FMN is similiar to FAD except?
it lacks the adenine nucleotide
58
NADH is ______to NAD+
| FAD is ______ to FADH2
oxidized; reduced
59
Complex 1 and Complex 2 are located on the ____side, while Complex 3 and Complex 4 are located on the ____ side
matrix; cytoplasmic
60
See Video about ETC
https://www.youtube.com/watch?v=xbJ0nbzt5Kw
61
During the electron transport there is _____ of electrons and ____ pumping of protons
spontaneous
| nonspontaneous
62
Protons go back thru synthase____ while ATP is created ____
spontaneous
| nonspontaneous
63
Fe3+ is the ___ form while Fe2+ is the ___ form.
oxidized; reduced
64
CoQ is hydrophobic or hydrophilic
hydrophobic in the the tails of the lipid bilayer
65
What are quinones?
compounds with a fully conjugated cyclic dione structure
66
How is QH2 produced?
The quinone ring of CoQ can be reduced to quinol in a 2e reaction
67
What is the prosthetic group of a cytochrome?
heme
68
Where all can CoQ accept electrons from?
Complex 1
Complex 2
G3P Dehydrogenase
69
Brief detail of Q cycle?
Q-(1e)->Q radical (semiquione radical)-(1e)->QH2
70
Complex 4 is the only component of the ETC that can
interact with oxygen due to copper
71
Oxygen is reduced to _____in complex 4, after the electrons are transfer from ____ to O2
water;cytochrome C
72
Although it happens one at a time, each electron in Complex 4 is passed due which order. What is being pumped?
cytochrome c->CuA->heme a->heme a3->CuB (STOPS)
| protons
73
The O2 in complex 4 form what?
peroxide bridge between heme a3 and cuB
74
What are the 2 enzymes that are scavengers of radical oxygens?
superoxide dismutase
| cataylase
75
What cleaves the peroxide bridge?
the addition of 2 more electrons and 2 more protons
76
Complex 1
transfers e's from NADH to quinone pool and pumps H+
77
Complex 2
transfers e's from succinate to quinone pool
78
Complex 3
transfers e's from quinol to cytochrome c and pumps H+
79
Complex 4
accepts e's from cytochrome c, reduces O2 to H2O and pumps H+
80
Complex 5
Harvests H+ gradient and regenerates ATP
81
Acid = more or less protons
MORE
82
gradient
difference in concentrations of molecules on either side of the membrane
83
electrochemical gradient
difference in protons and charges on each side of the membrane
84
____is the final electron acceptor, but then it is immediately _____to H2O
oxygen, reduced
85
ATP synthase makes ATP based off of what theory?
Chemiosmotic theory
86
What is the chemiosmotic theory?
the proton gradient is created by from the energy from electrons by pumping protons into the inner membrane space by complex 1,3,4
87
The process of osmosis is spontaneous or nonspontaneous?
nonspontaneous
88
How many hydrogen atoms have to flow through an ATP synthase to make ATP? What happens
3; There is a conformational change to produce ATP
89
Proton Motive Force
protons have a thermodynamic tendency to return to the matrix
90
Describe the experiment by Peter Mitchell (5)
1. Complex 5 was placed in a membrane vesicle
2. A known proton pump was placed in the vesicle (bacteriorhodopsin)
3. Added ADP+Pi
4. Shined UV light
5. ATP produced
91
What are the domains of ATP Synthase and where are they located?
Fo: inner mitochondrial membrane
F1: protrudes from the inner mitochondrial membrane into the matrix
92
What is the function of Fo of ATP Synthase? Components?
Proton Translocation
| C-C Ring
93
What is the function of F1 of ATP Synthase?Components?
ATP Synthesis and Hydrolysis
| 3 alternating alpha and beta subunits
94
What happens on the each subunits of the F1 region?
Alpha subunit: ADP can bind but no ATP made
| Beta subunit: ATP is synthesized
95
The conformational change of ATP Synthase is in response to?
the gamma rotation
96
3 Steps of ATP Production
L:Loose (ADP+Pi bind)
T:Tight (ATP made)
O:Open (ATP released)
97
How big is each rotation?
120 degrees
98
What are the 2 ways to stop ATP Synthesis?
Uncoupler or a blocker
99
What is the mechanism of an uncoupler?
prevents H+ from pumping to make ATP synthase instead H+ get into matrix another way
100
Glyercol 3 PDH Shuttle
DHAP is reduced to G3P; NADH is oxidized to NAD+ [cytosol]
| G3P-> DHAP; FAD is reduced to FADH2
101
Malate Aspartate Shuttle (more energy efficient)
Step 1: L-Asp ->oxaloacetate->malate [cytosol]
alpha ketoglumarate->glutamic acid
NADH->NAD+
Step2: malate->oxaloacetate->L-Asp [matrix]
NAD+-> NADH
glutamic acid->alpha ketoglumarate
102
What is a polymer of glucose?
glycogen
103
Where is glucose most predominantly stored as glycogen?
muscle and liver
104
Glucose stored in the liver/muscle is used for
bloodstream & glycolysis
105
What is the purpose of glycogen phosphorylase?
to the cleavage of phosphorolytic cleavage of alpha 1,4 glycosidic leakage of glycogen
one G1P is released
106
What serves as a prosthetic group for glycogen phosphorylase?
pyridoxal phosphate
107
What is the role of PLP (derivative of vitamin B6)?
acid base catalysis
108
NADH's can not cross the mitochondrial membrane, so what mechanism is used?
Glycerol 3 Phosphate Shuttle
| Malate Aspartate Shuttle
109
During Malate Aspartate Shuttle as glu goes in what comes out? As alpha keto goes out what comes in?
aspartic acid; malate
110
Enzyme: glycogen->G1P
glycogen phosphoylase
111
Enzyme: G1P->G6P
phosphoglucomutase
112
G6P can be transformed into what? (3)
G
PA
5-carbon sugar
113
What part does the glycogen phosphorylase attack?
non-reducing end "C-4 side"
114
What does PLP need?
5 glucose molecules
115
Local reciprocal regulation
concentration within the cell itself
116
Glycogen phosphorylase is _______
processive; it doesn't dissociate and reassociate between each cut
117
Debranching enzymes
have 2 independent active sites, consisting of residues in dif segments of a single polypeptide chain
establish alpha 1,6 linkage
118
What are 2 debranching enzymes
transferase & glucosidase
119
G1P->_____->glycogen
| What is the enzyme used?
glycogen synthase
120
When does regulation of glycogen phosphorylase work?
only when glycogen synthase does not
121
What are the 2 forms of phosphorylase? What position do they to be in?
A(R state:active) and B(T state:inactive)
122
What phosphorylase do muscle cells prefer? What puts this phosphorylase in the T and R?
B
AMP (put in R)
ATP and G6P (keep in T)
123
What phosphorylase do liver cells prefer?
A
124
Which phosphorylase has the phosphate?
A
125
Who puts the phosphate on phosphorylase?
glycogen phosphorylase kinase
126
Glycogenin
attaches glucose to Tyr to make a short polymer
127
What is a futile cycle?
if we break and make glycogen at the same time
128
What affects synthase activity?
ADP inhibits
| G6P activates
129
Types of Synthase
A(active: R) & B (inactive:T)
130
What type of Synthase is found in muscles/liver?
muscles: A (make G)
liver: B (break G)
131
What triggers the removal of phosphate?
insulin
132
Hormones in the brain and pancreas?
brain: adrenaline (put Pi on)
pancreas: insulin (take Pi off) & glucagon (put Pi on)
133
How do hormones tell a cell what to do?
via signal transduction
134
Receptor
membrane bound protein that binds the ligand and causes signal
135
Ligand
molecule that binds the receptor
