Question 1

In ketone body biosynthesis,the HMG-CoA lyase reaction is mechanistically the reverse of the first half of the reaction catalyzed by a particular TCA enzyme.Which of the following TCA enzymes does it resemble?

Accepted Answer

A)  aconitase
B)  citrate synthase
C)  malate dehydrogenase
D)  succinyl-CoA synthase B

Question 2

How do ketone body carbons enter the major metabolic pathways of the cells?

Accepted Answer

A)  by conversion to acetyl-CoA
B)  by conversion to citrate
C)  by conversion to pyruvate
D)  by conversion to glucose-6-phosphate A

Question 3

Which of the following tissues stores triacylglycerols?

Accepted Answer

A)  liver
B)  heart
C)  spleen
D)  fat D

Question 4

During ?-oxidation of certain unsaturated fatty acids,cis-?³-fatty acyl-CoAs are formed that must be converted to trans-?²-fatty acyl-CoAs.Which of the following enzymes converts them to trans-?²-fatty acyl-CoAs?

Accepted Answer

A)  acyl-CoA dehydrogenase
B)  enoyl-CoA dehydrogenase
C)  isocitrate dehydrogenase
D)  succinate dehydrogenase

Question 5

Which of the following steps is NOT a part of the sequence of events for activation of the release of fatty acids from adipose cells?

Accepted Answer

A)  triacylglycerol lipase inactivation
B)  adenylyl cyclase activation
C)  cAMP production
D)  hormone binding to the receptor

Question 6

Which of the following are the 3 most common ketone bodies?

Accepted Answer

A)  acetoacetate,hydroxyacetone phosphate,and butyrate
B)  acetone,β-hydroxybutyrate,and acetoacetate
C)  acetoacetate,acetyl-CoA,and acetone
D)  butyrate,acetoacetate,and acetone

Question 7

Which of the following hormones does NOT cause fatty acid mobilization in adipose cells?

Accepted Answer

A)  ACTH (adrenocorticotropic hormone) 
B)  glucagon
C)  insulin
D)  epinephrine (adrenaline)

Question 8

How many NAD⁺ are reduced in the b-oxidation of stearoyl-CoA to form 9 molecules of acetyl-CoA?

Accepted Answer

A)  8
B)  9
C)  12
D)  16

Question 9

Which of the following cellular locations is the site for where fatty acids are condensed with coenzyme A to form acyl-CoA for β-oxidation?

Accepted Answer

A)  mitochondrial matrix
B)  cytoplasm
C)  outer mitochondrial membrane
D)  inner mitochondrial membrane

Question 10

Which of the following classes of enzymes does enoyl-CoA hydratase belong to?

Accepted Answer

A)  transferase
B)  hydrolase
C)  lyase
D)  ligase

Question 11

Which of the following is NOT involved with the transport of fatty acyl groups from the cytosol to the matrix?

Accepted Answer

A)  carnitine acyltransferase I
B)  fatty acyl-CoA in matrix
C)  O-acylcarnitine
D)  ATP

Question 12

How many NADH are generated from the complete oxidation of palmitoyl-CoA to CO₂?

Accepted Answer

A)  21 by TCA plus 7 by β-oxidation
B)  24 by TCA plus 7 by β-oxidation
C)  24 by TCA plus 8 by β-oxidation
D)  28 by TCA plus 7 by β-oxidation

Question 13

Which of the following sequences of metabolic reactions is analogous to the first 3 reactions of ?-oxidation of saturated fatty acids?

Accepted Answer

A)  succinate? fumarate ?malate ?oxaloacetate
B)  isocitrate ? ?-ketoglutarat?e succinate ? fumarate
C)  oxaloacetate ?citrate? isocitrate ? ?-ketoglutarate
D)  phosphoenolpyruvate? pyruvate? acetyl-CoA? citrate

Question 14

Which of the following lipid components are produced in the duodenum by the enzyme pancreatic lipase during lipid digestion?

Accepted Answer

A)  diacylglycerols and fatty acids
B)  fatty acids and glycerol
C)  triacylglycerols and glycerol
D)  monoacylglycerols and fatty acids

Question 15

Which of the following series correctly describes the conversion of a fatty acid to CO₂?

Accepted Answer

A)  carnitine shuttle;activation to acyl-CoA;β-oxidation;CAC
B)  activation to acyl-CoA;carnitine shuttle;β-oxidation;CAC
C)  CAC;activation to acyl-CoA;β-oxidation;carnitine shuttle
D)  activation to acyl-CoA;β-oxidation;carnitine shuttle;CAC

Question 16

The first oxidation in the β-oxidation of saturated fatty acids is catalyzed by acyl-CoA dehydrogenase.Which of the following chemical conversions does it catalyze?

Accepted Answer

A)  a primary alcohol to an aldehyde
B)  a carbon-carbon single bond to a carbon-carbon double bond
C)  a secondary alcohol to a ketone
D)  an aldehyde to a carboxylic acid

Question 17

Which of the following TCA cycle intermediates is propionyl-CoA ultimately converted to?

Accepted Answer

A)  citrate
B)  isocitrate
C)  succinyl-CoA
D)  succinate

Question 18

Where are ketone bodies synthesized?

Accepted Answer

A)  cytosol of muscle
B)  mitochondria of liver
C)  endoplasmic reticulum of heart
D)  plasma membrane of brain

Question 19

How many times must the ?-oxidation cycle be repeated for the complete oxidation of a saturated fatty acid with 16 carbons?

Accepted Answer

A)  4
B)  6
C)  7
D)  8

Question 20

Which of the following is NOT a use for acetyl-CoA,a product of b-oxidation?

Accepted Answer

A)  synthesis of ketone bodies
B)  synthesis of amino acids
C)  catabolism in the TCA cycle
D)  synthesis of glucose

Exam 22: Fatty Acid Catabolism