MCQ Fatty acid Catabolism

Question 1

Lipoprotein lipase acts in:
A) hydrolysis of triacylglycerols of plasma lipoproteins to supply fatty acids to various tissues.
B) intestinal uptake of dietary fat.
C) intracellular lipid breakdown of lipoproteins.
D) lipoprotein breakdown to supply needed amino acids.
E) none of the above.

Answer 1

hydrolysis of triacylglycerols of plasma lipoproteins to supply fatty acids to various tissues.

Question 2

Free fatty acids in the bloodstream are:
A) bound to hemoglobin.
B) carried by the protein serum albumin.
C) freely soluble in the aqueous phase of the blood.
D) nonexistent; the blood does not contain free fatty acids.
E) present at levels that are independent of epinephrine.

Answer 2

carried by the protein serum albumin.

Question 3

The role of hormone-sensitive triacylglycerol lipase is to:
A) hydrolyze lipids stored in the liver.
B) hydrolyze membrane phospholipids in hormone-producing cells.
C) hydrolyze triacylglycerols stored in adipose tissue.
D) synthesize lipids in adipose tissue.
E) synthesize triacylglycerols in the liver.

Answer 3

hydrolyze triacylglycerols stored in adipose tissue.

Question 4

Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:
A) ATP, carnitine, and coenzyme A.
B) ATP, carnitine, and pyruvate dehydrogenase.
C) ATP, coenzyme A, and hexokinase.
D) ATP, coenzyme A, and pyruvate dehydrogenase.
E) carnitine, coenzyme A, and hexokinase.

Answer 4

A) ATP, carnitine, and coenzyme A.

Question 5

Fatty acids are activated to acyl-CoAs and the acyl group is further transferred to carnitine because:
A) acyl-carnitinesreadilycrossthemitochondrialinnermembrane,butacyl-CoAsdonot.
B) acyl-CoAs easily cross the mitochondrial membrane, but the fatty acids themselves will not.
C) carnitine is required to oxidize NAD+ to NADH.
D) fattyacidscannotbeoxidizedbyFADunlesstheyareintheacyl-carnitineform.
E) None of the above is true.

Answer 5

A) acyl-carnitinesreadilycrossthemitochondrialinnermembrane,butacyl-CoAsdonot.

Question 6

Carnitine is:
A) a15-carbonfattyacid.
B) an essential cofactor for the citric acid cycle.
C) essential for intracellular transport of fatty acids.
D) oneoftheaminoacidscommonlyfoundinprotein.
E) present only in carnivorous animals.

Answer 6

C) essential for intracellular transport of fatty acids.

Question 7

Which of these is able to cross the inner mitochondrial membrane?
A) Acetyl–CoA
B) Fatty acyl–carnitine
C) Fatty acyl–CoA
D) Malonyl–CoA
E) None of the above can cross.

Answer 7

B) Fatty acyl–carnitine

Question 8

What is the correct order of function of the following enzymes of β oxidation?
A) B) C) D) E)
1. β-Hydroxyacyl-CoA dehydrogenase 
2. Thiolase
3. Enoyl-CoA hydratase
4. Acyl-CoA dehydrogenase

1,2,3,4 
3,1,4,2 
4,3,1,2 
1,4,3,2
4,2,3,1

Answer 8

4,3,1,2

Question 9

If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the β-oxidation pathway and the citric acid cycle), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the net yield of ATP per molecule of palmitate is:
A) 3.
B) 10.
C) 25. D) 108. E) 1,000.

Answer 9

D) 108.

Question 10

Saturated fatty acids are degraded by the stepwise reactions of β oxidation, producing acetyl-CoA. Under aerobic conditions, how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?
A) 2 B) 3 C) 4 D) 5 E) 6

Answer 10

C) 4

Question 11

Which of the following is (are) true of the oxidation of 1 mol of palmitate (a 16-carbon saturated fatty acid; 16:0) by the β-oxidation pathway, beginning with the free fatty acid in the cytoplasm?
1. Activation of the free fatty acid requires the equivalent of two ATPs. 2. Inorganic pyrophosphate (PPi) is produced.
3. Carnitine functions as an electron acceptor. 4. 8 mol of FADH2 are formed.
5. 8 mol of acetyl-CoA are formed.
6. There is no direct involvement of NAD+.
A) 1and5only
B) 1,2,and5
C) 1,2,and6
D) 1,3,and5
E) 5 only

Answer 11

B) 1,2,and5

Question 12

Which of the following statements apply (applies) to the β oxidation of fatty acids?

1. The process takes place in the cytosol of mammalian cells.
2. Carbon atoms are removed from the acyl chain one at a time.
3. Before oxidation, fatty acids must be converted to their CoA derivatives.
4. NADP+ is the electron acceptor.
5. The products of β oxidation can directly enter the citric acid cycle for further oxidation.

Answer 12

D) 3 and 5 only

Question 13

Which of the following statements concerning the β oxidation of fatty acids is true?
A) About 1,200 ATP molecules are ultimately produced per 20-carbon fatty acid oxidized.
B) One FADH2 and two NADH are produced for each acetyl-CoA.
C) The free fatty acid must be carboxylated in the β position by a biotin-dependent reaction before
the process of β oxidation commences.
D) The free fatty acid must be converted to a thioester before the process of β oxidation
commences.
E) Two NADH are produced for each acetyl-CoA.

Answer 13

D) The free fatty acid must be converted to a thioester before the process of β oxidation
commences.

Question 14

The balanced equation for the degradation of CH3(CH2)10COOH via the β-oxidation pathway is:
A) CH3(CH2)10COOH + 5FAD + 5NAD+ + 6CoA—SH + 5H2O + ATP → 6 Acetyl-CoA + 5FADH2 + 5NADH + 5H+ + AMP + PPi
B) CH3(CH2)10COOH + 5FAD + 5NAD+ + 6CoA—SH + 5H2O → 6 Acetyl-CoA + 5FADH2 + 5NADH + 5H+
C) CH3(CH2)10COOH + 6FAD + 6NAD+ + 6CoA—SH + 6H2O + ATP → 6 Acetyl-CoA + 6FADH2 + 6NADH + 6H+ + AMP + PPi
D) CH3(CH2)10COOH + 6FAD + 6NAD+ + 6CoA—SH + 6H2O → 6 Acetyl-CoA + 6FADH2 + 6NADH + 6H+

Answer 14

CH3(CH2)10COOH + 5FAD + 5NAD+ + 6CoA—SH + 5H2O + ATP → 6 Acetyl-CoA + 5FADH2 + 5NADH + 5H+ + AMP + PPi

Question 15

Which compound is an intermediate of the β oxidation of fatty acids?
A) CH3—(CH2)20—CO—COOH
B) CH3—CH2—CO—CH2—CO—OPO32– C) CH3—CH2—CO—CH2—OH
D) CH3—CH2—CO—CO—S—CoA
E) CH3—CO—CH2—CO—S—CoA

Answer 15

E) CH3—CO—CH2—CO—S—CoA

Question 16

The conversion of palmitoyl-CoA (16:0) to myristoyl-CoA (14:0) and 1 mol of acetyl-CoA by the β- oxidation pathway results in the net formation of:
A) 1 FADH2 and 1 NADH.
B) 1 FADH2 and 1 NADPH.
C) 1 FADH2, 1 NADH, and 1 ATP.
D) 2 FADH2 and 2 NADH.
E) 2 FADH2, 2 NADH, and 1 ATP.

Answer 16

A) 1 FADH2 and 1 NADH.

Question 17

Which of the following is not true regarding the oxidation of 1 mol of palmitate (16:0) by the β- oxidation pathway?
A) 1 mol of ATP is needed.
B) 8 mol of acetyl-CoA are formed.
C) 8 mol of FADH2 are formed.
D) AMP and PPi are formed.
E) The reactions occur in the mitochondria.

Answer 17

C) 8 mol of FADH2 are formed.

Question 18

Which of the following is (are) true of the β oxidation of long-chain fatty acids?
1. The enzyme complex that catalyzes the reaction contains biotin. 2. FADH2 serves as an electron carrier.
3. NADH serves as an electron carrier.
4. Oxidation of an 18-carbon fatty acid produces six molecules of propionyl-CoA. 5. Oxidation of a 15-carbon fatty acid produces at least one propionyl-CoA.
A) 1,2,and3
B) 1,2,and5
C) 2,3,and4
D) 2,3,and5
E) 3 and 5 only

Answer 18

D) 2,3,and5

Question 19

The carbon atoms from a fatty acid with an odd number of carbons will enter the citric acid cycle as acetyl-CoA and:
A) butyrate.
B) citrate.
C) malate.
D) succinyl-CoA. E) α-ketoglutarate.

Answer 19

D) succinyl-CoA.

Question 20

During β oxidation of fatty acids, ___________ is produced in peroxisomes but not in mitochondria.
A) acetyl-CoA B) FADH2
C) H2O D) H2O2 E) NADH

Answer 20

D) H2O2

Question 21

Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as:
A) acetoacetyl-CoA.
B) acetone.
C) beta-hydroxybutyric acid.
D) beta-hydroxybutyryl-CoA.
E) lactic acid.

Answer 21

C) beta-hydroxybutyric acid.

Question 22

The major site of formation of acetoacetate from fatty acids is the:
A) adipose tissue.
B) intestinal mucosa.
C) kidney.
D) liver.
E) muscle.

Answer 22

D) liver.