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Biochemistry Theory Semester 1 > Fatty Acid Biosynthesis > Flashcards

Fatty Acid Biosynthesis Flashcards

1
Q

What is the role of the enzyme labeled ‘Acetyl-CoA carboxylase’ in this diagram?
[Insert diagram of fatty acid synthesis pathway]

A

A. Converts malonyl-CoA to acetyl-CoA
B. Converts acetyl-CoA to malonyl-CoA
C. Converts pyruvate to acetyl-CoA
D. Transports citrate
Correct Answer: B

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2
Q

Which structure in the diagram shows the site of fatty acid biosynthesis?
[Insert cell compartment diagram: mitochondria, cytosol, ER]

A

A. Mitochondria
B. Cytosol
C. Nucleus
D. ER
Correct Answer: B

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3
Q

Identify the labeled molecule acting as the acyl carrier in the fatty acid synthase complex.
[Insert FAS complex with ACP labeled]

A

A. ACP
B. CoA
C. NADPH
D. FAD
Correct Answer: A

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4
Q

Which part of this diagram shows β-oxidation of fatty acids?
[Insert schematic of fatty acid catabolism and synthesis]

A

A. Left section (cytosol)
B. Right section (mitochondria)
C. Top pathway (glycolysis)
D. None
Correct Answer: B

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5
Q

What is the final product labeled in the β-oxidation cycle diagram?
[Insert labeled cycle ending in acetyl-CoA]

A

A. Pyruvate
B. Lactate
C. Acetyl-CoA
D. Citrate
Correct Answer: C

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6
Q

Which molecule donates electrons during fatty acid biosynthesis?

A

A. NADH
B. NADPH
C. FADH2
D. ATP
Correct Answer: B

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7
Q

Where does β-oxidation of fatty acids occur?

A

A. Cytosol
B. Nucleus
C. Mitochondria
D. Golgi
Correct Answer: C

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8
Q

What distinguishes a synthetase from a synthase?

A

A. Synthases use ATP
B. Synthetases use ATP
C. Synthases make RNA
D. Synthetases break down proteins
Correct Answer: B

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9
Q

What enzyme initiates fatty acid synthesis by producing malonyl-CoA?

A

A. Fatty acid synthase
B. Acetyl-CoA carboxylase
C. Citrate lyase
D. Pyruvate carboxylase
Correct Answer: B

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10
Q

Which of the following is a product of β-oxidation?

A

A. NADPH
B. Glucose
C. Acetyl-CoA
D. Palmitate
Correct Answer: C

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11
Q

Assertion: Fatty acid biosynthesis occurs in the cytosol.
Reason: Enzymes involved in synthesis are cytoplasmic.

A

A. Both A and R are true, and R explains A.
Correct Answer: A

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12
Q

Assertion: NADPH is required for fatty acid biosynthesis.
Reason: NADPH acts as an oxidizing agent in the reactions.

A

C. A is true, but R is false.
Correct Answer: C

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13
Q

Assertion: Acetyl-CoA cannot cross the mitochondrial membrane directly.
Reason: It is converted to citrate for transport.

A

A. Both A and R are true, and R explains A.
Correct Answer: A

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14
Q

Assertion: β-oxidation produces ATP.
Reason: It produces acetyl-CoA, which enters the TCA cycle.

A

A. Both A and R are true, and R explains A.
Correct Answer: A

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15
Q

Assertion: Synthases require ATP to function.
Reason: Synthases hydrolyze ATP to form products.

A

D. A is false, R is false.
Correct Answer: D

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16
Q

Fatty acid synthesis takes place in the mitochondria.

A

False

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17
Q

β-oxidation breaks down fatty acids into acetyl-CoA.

A

True

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18
Q

Synthetases require ATP to function.

A

True

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19
Q

Malonyl-CoA is a key intermediate in fatty acid biosynthesis.

A

True

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20
Q

Acetyl-CoA carboxylase uses CO2 to convert acetyl-CoA to malonyl-CoA.

A

True

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21
Q

The fatty acid synthase complex uses NADH for reduction steps.

A

False

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22
Q

The end product of fatty acid synthesis is palmitate.

A

True

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23
Q

Acyl-CoA is an intermediate in fatty acid degradation.

A

True

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24
Q

Hydratase enzymes add water to a double bond.

A

True

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25
Citrate can carry acetyl-CoA out of the mitochondria.
True
26
What enzyme is indicated in the step converting β-ketoacyl-ACP to β-hydroxyacyl-ACP? [Insert labeled FAS cycle diagram]
A. Ketoacyl-ACP reductase B. Enoyl-ACP reductase C. Acetyl-CoA carboxylase D. Enoyl-CoA hydratase Correct Answer: A
27
Which reaction in the β-oxidation spiral produces NADH? [Insert diagram of β-oxidation with labeled steps]
A. Acyl-CoA dehydrogenase B. Hydroxyacyl-CoA dehydrogenase C. Thiolase D. Enoyl-CoA hydratase Correct Answer: B
28
In this diagram, what role does malic enzyme play in fatty acid synthesis integration? [Insert integration pathway diagram: glycolysis, NADPH, malate]
A. Converts oxaloacetate to citrate B. Produces NADPH by converting malate to pyruvate C. Transfers citrate into mitochondria D. Forms acetyl-CoA from pyruvate Correct Answer: B
29
What is the enzyme responsible for condensation of acetyl and malonyl groups in this cycle? [Insert FAS cycle with condensation labeled]
A. Enoyl reductase B. Ketoacyl-ACP synthase C. Hydratase D. Malonyl-CoA transacylase Correct Answer: B
30
What component carries the elongating fatty acid chain in this system? [Insert fatty acid synthase structure highlighting carrier proteins]
A. CoA B. ACP2 with phosphopantetheine C. ACP1 with cysteinyl group D. NADPH-binding domain Correct Answer: B
31
Which enzyme activates acetyl-CoA for fatty acid synthesis?
A. Acetyl-CoA synthetase B. Acetyl-CoA carboxylase C. Citrate lyase D. Fatty acid synthase Correct Answer: B
32
What is the end product of the fatty acid synthase complex?
A. Acetyl-CoA B. Palmitoyl-ACP C. Stearoyl-CoA D. Acetoacetate Correct Answer: B
33
In β-oxidation, which cofactor is used by acyl-CoA dehydrogenase?
A. NAD+ B. NADPH C. FAD D. CoA Correct Answer: C
34
Which of the following is NOT an intermediate in β-oxidation?
A. Acyl-CoA B. Enoyl-CoA C. Malonyl-CoA D. Hydroxyacyl-CoA Correct Answer: C
35
What makes unsaturated fatty acids appear shorter in elongation systems?
A. Their double bonds allow rapid oxidation B. Cis double bonds create bends affecting enzyme binding C. They require more NADPH D. Their carbon number is lower Correct Answer: B
36
Assertion: Malonyl-CoA inhibits β-oxidation. Reason: Malonyl-CoA blocks carnitine shuttle transport of fatty acids.
A. Both A and R are true, and R explains A. Correct Answer: A
37
Assertion: NADPH is essential for fatty acid synthesis. Reason: NADPH is generated through the pentose phosphate and malic enzyme pathways.
A. Both A and R are true, and R explains A. Correct Answer: A
38
Assertion: The ER-based elongation system synthesizes fatty acids longer than C16. Reason: This system contains individual enzymes not found in the cytosolic FAS complex.
A. Both A and R are true, and R explains A. Correct Answer: A
39
Assertion: Fatty acid synthesis and β-oxidation occur in the same cell compartment. Reason: Both require CoA derivatives of fatty acids.
C. A is false, R is true. Correct Answer: C
40
Assertion: β-oxidation of fatty acids occurs in the ER. Reason: ER contains enzymes for very long chain fatty acid metabolism.
D. A is false, R is true. Correct Answer: D
41
ACP2 carries the growing fatty acid chain in FAS complex.
True
42
NADPH is generated in mitochondria for fatty acid synthesis.
False
43
β-ketoacyl reductase uses NADPH as a cofactor.
True
44
Enoyl-ACP reductase catalyzes the final reduction in each FAS cycle.
True
45
Malonyl-CoA is involved in both synthesis and oxidation of fatty acids.
False
46
Citrate transports acetyl-CoA across mitochondrial membranes.
True
47
Fatty acid elongation in mitochondria depends on NADH.
False
48
Thioesterase terminates synthesis by releasing palmitate.
True
49
The citrate-pyruvate shuttle provides both acetyl-CoA and NADPH.
True
50
Hydratase enzymes catalyze hydration of enoyl intermediates.
True
51
Which enzyme in this mitochondrial β-oxidation cycle transfers an acetyl group to CoA? [Insert labeled β-oxidation diagram]
A. Enoyl-CoA hydratase B. Hydroxyacyl-CoA dehydrogenase C. Thiolase D. Acyl-CoA synthetase Correct Answer: C
52
What molecule is shown as the reducing cofactor in ER-based elongation for mitochondrial fatty acids? [Insert elongation pathway with NADPH/FAD labeled]
A. FADH2 B. NADH C. NADPH D. Ubiquinone Correct Answer: C
53
Which component in this diagram represents the citrate-pyruvate shuttle? [Insert integration pathway with citrate, malate, pyruvate arrows]
A. NADH to mitochondria B. Acetyl-CoA to cytosol and NADPH production C. Pyruvate to glucose conversion D. Oxidation of fatty acids Correct Answer: B
54
What does the diagram indicate as the function of ACP1 vs ACP2? [Insert FAS complex showing two carrier domains]
A. ACP1 holds growing chain; ACP2 activates malonyl-CoA B. ACP1 holds acetyl group; ACP2 carries growing chain C. ACP1 binds malonyl; ACP2 synthesizes ATP D. Both bind palmitate Correct Answer: B
55
What is indicated by the enzyme converting palmitate to stearoyl-CoA in this ER pathway? [Insert diagram showing elongation from C16 to C18]
A. Thioesterase B. Mitochondrial FAS C. ER elongation system D. Peroxisomal synthase Correct Answer: C
56
Which enzyme replaces FAD-dependent dehydrogenase in mitochondrial elongation?
A. Enoyl-CoA reductase (NADPH-dependent) B. Ketoacyl synthase C. Enoyl-ACP reductase D. NADH oxidase Correct Answer: A
57
What is the function of the citrate shuttle in fatty acid synthesis?
A. Directly imports acetyl-CoA to cytosol B. Exports pyruvate from cytosol C. Transfers reducing equivalents only D. Transports acetyl equivalents and enables NADPH generation Correct Answer: D
58
Which of the following enzymes catalyzes dehydration in the FAS cycle?
A. β-ketoacyl-ACP reductase B. Enoyl-ACP reductase C. Enoyl-ACP hydrase D. Ketoacyl-ACP synthase Correct Answer: C
59
What causes accumulation of odd-chain fatty acid degradation intermediates?
A. Lack of thiolase B. Accumulation of propionyl-CoA C. Accumulation of NADPH D. Inhibition of citrate shuttle Correct Answer: B
60
What is the energetic cost of synthesizing one molecule of palmitate from acetyl-CoA?
A. 7 ATP, 14 NADH B. 7 ATP, 14 NADPH C. 14 ATP, 7 NADPH D. 8 ATP, 16 NADH Correct Answer: B
61
Assertion: Fatty acid synthesis requires both ATP and NADPH. Reason: ATP is required for carboxylation and NADPH for reduction steps.
A. Both A and R are true, and R explains A. Correct Answer: A
62
Assertion: The mitochondrial elongation system uses the same enzymes as β-oxidation. Reason: It operates in reverse with NADPH replacing FAD.
A. Both A and R are true, and R explains A. Correct Answer: A
63
Assertion: Thioesterase is needed in fatty acid biosynthesis termination. Reason: It hydrolyzes the bond between the fatty acid and the ACP domain.
A. Both A and R are true, and R explains A. Correct Answer: A
64
Assertion: Unsaturated fatty acids inhibit their own elongation. Reason: Kinks in their structure affect binding to elongation enzymes.
A. Both A and R are true, and R explains A. Correct Answer: A
65
Assertion: All fatty acids longer than C16 are made in mitochondria. Reason: ER contains enzymes to shorten fatty acids only.
D. A is false, R is false. Correct Answer: D
66
NADPH replaces FADH2 in the mitochondrial elongation system.
True
67
Propionyl-CoA is a product of even-chain fatty acid β-oxidation.
False
68
Fatty acid elongation in mitochondria resembles reversed β-oxidation.
True
69
Acetyl-CoA can freely cross mitochondrial membranes.
False
70
Palmitate is the typical product of cytosolic fatty acid synthesis.
True
71
Ketoacyl synthase condenses malonyl-ACP and acyl-ACP.
True
72
Fatty acid synthesis and elongation are regulated at the level of ACP binding.
True
73
The ER elongation system cannot process unsaturated fatty acids.
False
74
The mitochondrial elongation system is dependent on NADH.
False
75
Malic enzyme generates pyruvate and NADPH.
True

Biochemistry Theory Semester 1 (12 decks)

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