UNE medical biochemistry Unit 3 Questions and Answers
In the fasted state, fatty acyl-CoA are transported across the mitochondrial
membrane. The transport of fatty acids via carnitine palmitoyl transferase I (CPTI)
can be directly inhibited by which of the following compounds?
a. Malonyl CoA
b. Carnitine
c. Acetyl CoA
d. Palmitate
Malonyl CoA
Under fasting conditions (ratio of insulin to glucagon <1), elevated glucagon will
activate which of the following enzymes?
a. glycogen synthase
b. lipoprotein lipase
c. hormone sensitive lipase
d. pyruvate dehydrogenase complex
hormone sensitive lipase
ATP can be generated by many metabolic pathways in the body. Which of the
following processes generates the most ATP?
a. glycogenolysis
b. fatty acid β-oxidation
c. pentose phosphate pathway
d. citric acid cycle
Fatty acid β-oxidation
In liver, which of the following key inhibitory events ensures that newly
synthesized palmitoyl-CoA is not immediately oxidized?
a. Inhibition of CPT-II by acetyl-CoA
b. Inhibition of CPT-I by malonyl-CoA
c. Inhibition of CPT-I by palmitoyl-carnitine
d. Inhibition of acyl-CoA synthetase by malonyl-CoA
Inhibition of CPT-I by malonyl-CoA
Ketonuria, hyperglycemia and severe acidosis are prime diagnostic indicators of
the presentation of Type I diabetic ketoacidosis. Which of the following
compounds are "ketone bodies" that would be elevated in serum and urine of a
patient in this condition?
a. fumarate and succinate
b. pyruvate and lactate
c. acetone and ethanol
d. D-3-hydroxybutyrate and acetoacetate
e. oxaloacetate and pyruvate
D-3-hydroxybutyrate and acetoacetate
Which of the following is NOT a product of β-oxidation?
a. NADH
b. FADH2
c. NADPH
d. Acetyl-CoA
, NADPH
A well, 2-year-old girl 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 by I.V. Additional laboratory tests showed elevated
medium-chain fatty acyl carnitines in blood and 6-8 carbon dicarboxylic acids in
the urine. Which of the following abnormalities is the most likely diagnosis for
this child?
Defect of medium-chain coenzyme A dehydrogenase
An individual is on a hunger strike and has not eaten in 13 days. Which of the
following best describes their metabolic state?
a. glycolysis will be highly active
b. the brain will be preferentially oxidizing ketones
c. glycogenolysis will be the primary source of blood glucose
d. skeletal muscle will be primarily oxidizing glucose
the brain will be preferentially oxidizing ketones (under conditions of starvation, the
brain will begin to oxidize ketones as a primary fuel source reducing it's reliance on
glucose)
Insulin stimulates lipogenesis through several mechanisms. Which of the
following is NOT an insulin stimulated process that enhances lipogenesis?
a. decreased activity of the PDC
b. increased glucose transport into the cells
c. decreased levels of cAMP
d. increased activity of acetyl-coA carboxylase
decreased activity of the PDC
(insulin stimulates the PDC)
Fatty acid synthase is a multimeric enzyme complex. Which of the following
subunits contains pantothenic acid as a cofactor?
a. enoyl reductase
b. thioesterase
c. ketoacyl synthase
d. acyl carrier protein (ACP)
acyl carrier protein (ACP)
Under fasting conditions, acetyl CoA carboxylase will be inhibited by an increase
in which of the following compounds?
a. citrate
b. glucose
c. malonyl-CoA
d. fatty acyl-CoA
fatty acyl-CoA
During fatty acid synthesis, after the initial step involving acetyl-CoA, the fatty
acid chain is elongated by the addition of which of the following compounds?
a. Acyl-CoA
b. Succinyl-CoA
In the fasted state, fatty acyl-CoA are transported across the mitochondrial
membrane. The transport of fatty acids via carnitine palmitoyl transferase I (CPTI)
can be directly inhibited by which of the following compounds?
a. Malonyl CoA
b. Carnitine
c. Acetyl CoA
d. Palmitate
Malonyl CoA
Under fasting conditions (ratio of insulin to glucagon <1), elevated glucagon will
activate which of the following enzymes?
a. glycogen synthase
b. lipoprotein lipase
c. hormone sensitive lipase
d. pyruvate dehydrogenase complex
hormone sensitive lipase
ATP can be generated by many metabolic pathways in the body. Which of the
following processes generates the most ATP?
a. glycogenolysis
b. fatty acid β-oxidation
c. pentose phosphate pathway
d. citric acid cycle
Fatty acid β-oxidation
In liver, which of the following key inhibitory events ensures that newly
synthesized palmitoyl-CoA is not immediately oxidized?
a. Inhibition of CPT-II by acetyl-CoA
b. Inhibition of CPT-I by malonyl-CoA
c. Inhibition of CPT-I by palmitoyl-carnitine
d. Inhibition of acyl-CoA synthetase by malonyl-CoA
Inhibition of CPT-I by malonyl-CoA
Ketonuria, hyperglycemia and severe acidosis are prime diagnostic indicators of
the presentation of Type I diabetic ketoacidosis. Which of the following
compounds are "ketone bodies" that would be elevated in serum and urine of a
patient in this condition?
a. fumarate and succinate
b. pyruvate and lactate
c. acetone and ethanol
d. D-3-hydroxybutyrate and acetoacetate
e. oxaloacetate and pyruvate
D-3-hydroxybutyrate and acetoacetate
Which of the following is NOT a product of β-oxidation?
a. NADH
b. FADH2
c. NADPH
d. Acetyl-CoA
, NADPH
A well, 2-year-old girl 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 by I.V. Additional laboratory tests showed elevated
medium-chain fatty acyl carnitines in blood and 6-8 carbon dicarboxylic acids in
the urine. Which of the following abnormalities is the most likely diagnosis for
this child?
Defect of medium-chain coenzyme A dehydrogenase
An individual is on a hunger strike and has not eaten in 13 days. Which of the
following best describes their metabolic state?
a. glycolysis will be highly active
b. the brain will be preferentially oxidizing ketones
c. glycogenolysis will be the primary source of blood glucose
d. skeletal muscle will be primarily oxidizing glucose
the brain will be preferentially oxidizing ketones (under conditions of starvation, the
brain will begin to oxidize ketones as a primary fuel source reducing it's reliance on
glucose)
Insulin stimulates lipogenesis through several mechanisms. Which of the
following is NOT an insulin stimulated process that enhances lipogenesis?
a. decreased activity of the PDC
b. increased glucose transport into the cells
c. decreased levels of cAMP
d. increased activity of acetyl-coA carboxylase
decreased activity of the PDC
(insulin stimulates the PDC)
Fatty acid synthase is a multimeric enzyme complex. Which of the following
subunits contains pantothenic acid as a cofactor?
a. enoyl reductase
b. thioesterase
c. ketoacyl synthase
d. acyl carrier protein (ACP)
acyl carrier protein (ACP)
Under fasting conditions, acetyl CoA carboxylase will be inhibited by an increase
in which of the following compounds?
a. citrate
b. glucose
c. malonyl-CoA
d. fatty acyl-CoA
fatty acyl-CoA
During fatty acid synthesis, after the initial step involving acetyl-CoA, the fatty
acid chain is elongated by the addition of which of the following compounds?
a. Acyl-CoA
b. Succinyl-CoA
