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Essential Biochemistry - Biological Oxidation (Section 1)

1
Which of the following molecules is a product of the electron transport chain?
Answer
(C)
ATP
2
Which molecule is directly involved in the transfer of electrons from FADH2 to the electron transport chain?
Answer
(B)
Coenzyme Q
3
Which component of the ETC is associated with complex II?
Answer
(B)
Succinate dehydrogenase
4
In energy currency of the cell is:
Answer
(A)
High energy phosphate (~P)
5
Which of the following shuttles regenerates NAD+ in the cytosol, allowing glycolysis to continue under anaerobic conditions?
Answer
(B)
Glycerol 3-phosphate shuttle
6
Which of the following is an example of substrate-level phosphorylation?
Answer
(C)
The synthesis of ATP from ADP and Pi during glycolysis
7
What is the correct order of electron flow in the electron transport chain?
Answer
A
B
8
What is the role of Complex IV (cytochrome c oxidase) in the electron transport chain?
Answer
(B)
To reduce oxygen to water.
9
What happens to the energy released during electron transport?
Answer
(D)
Both released as heat and used to pump protons.
10
What process is directly inhibited by cyanide?
Answer
(D)
Complex IV
11
Which molecule is required as a terminal electron acceptor in the electron transport chain?
Answer
(C)
Oxygen
12
What is the role of uncoupling proteins (UCPs)?
Answer
(C)
To allow protons to bypass ATP synthase
13
What is the primary function of Complex III in the electron transport chain?
Answer
(D)
To transfer electrons from CoQ to cytochrome c
14
What type of reaction does dehydrogenase catalyze?
Answer
(A)
Oxidation
15
In oxidative phosphorylation, the oxidation of one molecule of NADH produces
Answer
(B)
3 ATP molecules
16
What is the purpose of uncoupling agents like 2,4-dinitrophenol (DNP)?
Answer
(C)
To allow protons to bypass ATP synthase and reduce ATP synthesis
17
The uncoupling of oxidative phosphorylation
Answer
(C)
Inhibit ATP synthesis but not electron transport
18
Which complex in the electron transport chain pumps protons across the inner mitochondrial membrane?
Answer
A
D
C
19
What is the role of Coenzyme Q in the electron transport chain?
Answer
A
B
C
20
What is the role of the proton gradient in oxidative phosphorylation?
Answer
(C)
To provide the energy for ATP synthesis
21
Which of the following is a mobile electron carrier in the electron transport chain?
Answer
A
B
22
Which of the following molecules inhibits ATP synthase?
Answer
(C)
Oligomycin
23
Which of the following statements is true regarding the role of Coenzyme Q (CoQ) in the electron transport chain?
Answer
(B)
CoQ is a mobile carrier of electrons.
24
Which of the following is NOT a proton-pumping complex in the ETC?
Answer
(B)
Complex II
25
Where does the electron transport chain occur in the mitochondria?
Answer
(B)
The inner mitochondrial membrane
26
The flow of electrons through the electron transport chain results in:
Answer
(D)
All of the above
27
Which of the following is a mobile carrier of electrons in the ETC?
Answer
(C)
Cytochrome c
28
Which enzyme complex is responsible for synthesizing ATP?
Answer
(C)
ATP synthase
29
Which of the following molecules donates electrons to the electron transport chain?
Answer
(C)
NADH
30
Respiratory chain is found in:
Answer
(A)
Mitochondria
31
The oxidation and phosphorylation of intact mitochondria is blocked by:
Answer
(D)
All of them
32
In the malate-aspartate shuttle, what molecule is directly involved in transporting reducing equivalents across the inner mitochondrial membrane?
Answer
(A)
Malate
33
In the chemiosmotic theory, what drives ATP synthesis?
Answer
(B)
The proton gradient
34
What would be the expected result of a deficiency in cytochrome c?
Answer
(B)
Impaired electron transport
35
Which complex directly oxidizes succinate?
Answer
(B)
Complex II
36
What is the role of the inner mitochondrial membrane in oxidative phosphorylation?
Answer
(D)
All of the above
37
Which of the following correctly represents the order of electron flow in the electron transport chain, starting with NADH?
Answer
(A)
NADH -> Complex I -> CoQ -> Complex III -> Cytochrome c -> Complex IV -> O2
38
Which of the following is a characteristic of substrate-level phosphorylation?
Answer
(B)
It directly produces ATP without the use of a proton gradient
39
What is the role of Complex II in the electron transport chain?
Answer
(A)
To oxidize FADH2 and transfer electrons to CoQ
40
Enzyme that synthesizes ATP in oxidative phosphorylation is
Answer
(A)
Reactase
41
Which one of the following respiratory chain components reacts directly with molecular oxygen?
Answer
(A)
Cytochrome a3
42
Which of the following trace elements has role in ETC?
Answer
(D)
Zinc
43
Which of the following molecules is directly reoxidized by complex IV?
Answer
(B)
Cytochrome c
44
In oxidative phosphorylation, the oxidation of one molecule of FADH2 produces
Answer
(B)
2 ATP molecules
45
What is the primary function of Coenzyme Q (Ubiquinone)?
Answer
(A)
To transfer electrons from complex I to complex III
46
Which of the following shuttles is used to transport NADH equivalents across the inner mitochondrial membrane?
Answer
A
B
47
Which complex in the electron transport chain does NOT pump protons?
Answer
(B)
Complex II
48
Which of the following is the primary function of complex I?
Answer
(C)
To pump protons and transfer electrons from NADH to CoQ
49
A biochemically substance that you act on as an uncoupler is:
Answer
(B)
Free fatty acid
50
Which of the following is an inhibitor of the electron transport chain?
Answer
(B)
Rotenone