Questions And 100% Correct Answers
2025-2026 Updated.
A 55-year-old male is diagnosed with Type 2 diabetes and his current presentation is consistent
with a lack of insulin production. Serum levels of free fatty acids were elevated in this individual
primarily due to increased activity of which of the following enzymes?
Carnitine palmitoyl transferase I
Carbamoyl phosphate synthetase I
Hormone-sensitive lipase
Glutamate dehydrogenase - Answer Hormone-sensitive lipase
β- oxidation of long-chain fatty acids is inhibited by:
Pantothenic Acid (vitamin B5)
Carnitine
Malonyl-CoA
Fatty acids - Answer Malonyl-CoA
Which of the following represents the correct sequence of events in a cycle of β-oxidation
beginning with a saturated fatty acyl-CoA?
NAD+-coupled oxidation, FAD-coupled oxidation, hydration, thiolytic cleavage
NAD+-coupled oxidation, hydration, FAD-coupled oxidation, thiolytic cleavage
hydration, FAD-coupled oxidation, NAD+-coupled oxidation, thiolytic cleavage
FAD-coupled oxidation, hydration, NAD+-coupled oxidation, thiolytic cleavage
FAD-coupled oxidation, NAD+-coupled oxidation, hydration, thiolytic cleavage - Answer FAD-
coupled oxidation, hydration, NAD+-coupled oxidation, thiolytic cleavage
Glucose cannot be synthesized from the β-oxidation of even chain fatty acids because:
Insulin levels are elevated when fatty acids are being oxidized
The acetyl-CoA produced from β-oxidation is completely oxidized in the TCA cycle
Acetyl-CoA produced in the β-oxidation of fatty acids cannot be transported out of the
mitochondrial matrix
,Gluconeogenesis is inhibited by acetyl-CoA produced in the β-oxidation of fatty acids - Answer
The acetyl-CoA produced from β-oxidation is completely oxidized in the TCA cycle
A well, 2-year-old female presents to the clinic with symptoms of a viral illness. Her parents
report she has had bouts of vomiting and diarrhea over the last 24 hours. This morning they
could barely wake her from her crib and she was very weak. Laboratory tests show low blood
glucose (hypoglycemia) and elevated liver enzymes. There are no ketones present in her urine.
The child is hospitalized and glucose is administered I.V. Additional laboratory analysis showed
elevated medium-chain fatty acylcarnitines in blood and 6-8 carbon dicarboxylic acids in the
urine. Which of the following abnormalities is the most likely diagnosis for this child?
Mitochondrial defect in fatty acid transport
Defect of medium-chain fatty acyl synthetase
Carnitine deficiency
Defect of medium-chain coenzyme A dehydrogenase
Mitochondrial defect in the electron transport chain - Answer Defect of medium-chain
coenzyme A dehydrogenase
A 1-year-old female presents to the emergency room with hypoglycemia following a brief
seizure. After laboratory tests, a deficiency in β-oxidation is confirmed. This could potentially be
caused by a deficiency in an enzyme or reduced levels of which of the following cofactors are
required for this process?
Pyridoxal phosphate
Carnitine
Thiamine
Biotin - Answer Carnitine
An 11-year-old female is brought to the emergency department by her parent. They report she
has recently been very thirsty and needs to make frequent trips to the bathroom. Physical
examination revealed a thin girl in the 30th percentile for height and weight. A rapid dipstick
test revealed glucose in her urine. Evaluation of this girl's blood would reveal decreased levels
of which of the following compounds or hormones?
Glutamine
Ketones
Fatty acids
Insulin
Glucose - Answer Insulin
, What is the compound formed from the spontaneous decarboxylation of acetoacetate in the
blood that is responsible for a fruity odor on the breath of someone with ketonemia?
β-hydroxybutyrate
Succinyl-CoA
Acetyl-CoA
Acetone - Answer Acetone
Fatty acid synthase is a multimeric enzyme complex. Which of the following subunits contains
pantothenic acid as a cofactor?
Thioesterase
Ketoacyl synthase
Acyl carrier protein (ACP)
Enoyl reductase - Answer Acyl carrier protein (ACP)
Acetyl-CoA Carboxylase will be active when which of the following hormones is elevated?
Epinephrine
Cortisol
Glucagon
Insulin - Answer Insulin
Under conditions when glucose oxidation is elevated, the acetyl-CoA produced will allosterically
activate which of the following enzymes leading to an increase in the production of
oxaloacetate?
Acetyl CoA carboxylase
Malate dehydrogenase
Pyruvate carboxylase
Citrate lyases - Answer Pyruvate carboxylase
Which of the following enzymes is correctly paired with its allosteric inhibitor?
Pyruvate kinase: fructose 1,6-bisphosphate
Carnitine palmitoyltransferase I: acetyl-CoA