UNE Biochem FINAL |83 Questions| With 100% Verified
& Passed Solutions.
An individual goes to bed around 8 pm and doesn't wake up until 9 am the next
morning. During this time, which of the following is the primary oxidizable
substrate in the skeletal muscle?
Free fatty acids
Under fasted conditions as described above, the skeletal muscle and liver would be
oxidizing free fatty acids as a means of producing ATP.
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 analysis 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 acyl-dehydrogenase
This presentation is consistent with a deficiency in medium-chain acyl-dehydrogenase.
The lack of ketones suggests a deficiency in β-oxidation and the presence of medium
chain carnitines and dicarboxylic acids suggest products of omega-oxidation.
The process of ketogenesis refers to the conversion of acetyl-CoA to which of the
following compounds?
D-3-hydroxybutyrate or β-hydroxybutyrate
Ketogenesis is the process by which excess acetyl-CoA from β-oxidation is converted to
the ketone bodies: D-3-hydroxybutyrate (β-hydroxybutyrate) and acetoacetate.
During the fasted state, lipolysis is facilitated by the action of hormone sensitive
lipase. This enzyme requires which of the following modifications for activation?
Phosphorylation
Glucagon will increase levels of lipolysis through the phosphorylation and activation of
hormone sensitive lipase.
ATP can be generated by many metabolic pathways in the body. Which of the
following processes generates the most ATP?
Fatty acid β-oxidation
7 NADH, 7 FADH2 and 8 acetyl-CoA are all produced by β-oxidation of a C16 fatty acid.
This will generate 108 mol ATP/ mol palmitate.
Under fasting conditions (ratio of insulin to glucagon <1), elevated glucagon will
activate which of the following enzymes?
, Hormone sensitive lipase
Glucagon will increase levels of lipolysis through the phosphorylation and activation of
hormone sensitive lipase.
An individual is on a hunger strike and has not eaten in 13 days. Which of the
following best describes their metabolic state?
The brain will be preferentially oxidizing ketones.
Under conditions of excess fasting (i.e. starvation), the brain will begin to oxidize
ketones as a primary fuel source reducing its reliance on glucose.
An 11-year-old girl is brought to the emergency department by her father. He
reports she has recently been very thirsty and needing to make frequent trips to
the bathroom. At her soccer game today, she complained of lightheadedness and
the symptoms did not resolve even after drinking a power beverage. A rapid
dipstick test revealed glucose in her urine and further diagnostics were
consistent with a diagnosis of type 1 diabetes. Evaluation of this girl's liver would
reveal an increased rate of which of the following processes?
Ketogenesis
The description here is of type 1 diabetes which is consistent with a loss of insulin
production. Therefore, fasted state metabolic pathways would be highly active
contributing to hyperglycemia and ketogenesis. The other pathways listed would be
active in the fed state or when insulin is high.
Which of the following enzymes is correctly paired with its allosteric inhibitor?
Acetyl-CoA carboxylase: palmitoyl-CoA
The regulatory step in fatty acid synthesis is the synthesis of malonyl-CoA by acetyl-
CoA carboxylase. This enzyme can be inhibited by fatty acyl-CoA . Elevated fatty acyl-
CoA will also inhibit the tricarboxylate transporter and reduce citrate efflux from the
TCA.
A defect in the thioesterase subunit of fatty acid synthase would impair which of
the following activities of the enzyme complex?
Liberation of newly assembled palmitate from the enzyme
Fatty acid synthase is a multimeric enzyme and the final and sixth enzyme in the chain
is the thioesterase which will liberate the newly formed palmitate.
Under fasting conditions, acetyl-CoA carboxylase will be inhibited by an increase
in which of the following compounds?
fatty acyl-CoA
In fasting conditions when lipolysis is active, an increase in fatty acyl-CoA in the cell for
the process of β-oxidation will decrease citrate efflux from the mitochondria and activity
of acetyl-CoA carboxylase.
An increase in the ratio of insulin to glucagon will increase the activity of which
of the following enzymes (+ indicates activity is increased; - indicates activity is
not increased by insulin)?
& Passed Solutions.
An individual goes to bed around 8 pm and doesn't wake up until 9 am the next
morning. During this time, which of the following is the primary oxidizable
substrate in the skeletal muscle?
Free fatty acids
Under fasted conditions as described above, the skeletal muscle and liver would be
oxidizing free fatty acids as a means of producing ATP.
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 analysis 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 acyl-dehydrogenase
This presentation is consistent with a deficiency in medium-chain acyl-dehydrogenase.
The lack of ketones suggests a deficiency in β-oxidation and the presence of medium
chain carnitines and dicarboxylic acids suggest products of omega-oxidation.
The process of ketogenesis refers to the conversion of acetyl-CoA to which of the
following compounds?
D-3-hydroxybutyrate or β-hydroxybutyrate
Ketogenesis is the process by which excess acetyl-CoA from β-oxidation is converted to
the ketone bodies: D-3-hydroxybutyrate (β-hydroxybutyrate) and acetoacetate.
During the fasted state, lipolysis is facilitated by the action of hormone sensitive
lipase. This enzyme requires which of the following modifications for activation?
Phosphorylation
Glucagon will increase levels of lipolysis through the phosphorylation and activation of
hormone sensitive lipase.
ATP can be generated by many metabolic pathways in the body. Which of the
following processes generates the most ATP?
Fatty acid β-oxidation
7 NADH, 7 FADH2 and 8 acetyl-CoA are all produced by β-oxidation of a C16 fatty acid.
This will generate 108 mol ATP/ mol palmitate.
Under fasting conditions (ratio of insulin to glucagon <1), elevated glucagon will
activate which of the following enzymes?
, Hormone sensitive lipase
Glucagon will increase levels of lipolysis through the phosphorylation and activation of
hormone sensitive lipase.
An individual is on a hunger strike and has not eaten in 13 days. Which of the
following best describes their metabolic state?
The brain will be preferentially oxidizing ketones.
Under conditions of excess fasting (i.e. starvation), the brain will begin to oxidize
ketones as a primary fuel source reducing its reliance on glucose.
An 11-year-old girl is brought to the emergency department by her father. He
reports she has recently been very thirsty and needing to make frequent trips to
the bathroom. At her soccer game today, she complained of lightheadedness and
the symptoms did not resolve even after drinking a power beverage. A rapid
dipstick test revealed glucose in her urine and further diagnostics were
consistent with a diagnosis of type 1 diabetes. Evaluation of this girl's liver would
reveal an increased rate of which of the following processes?
Ketogenesis
The description here is of type 1 diabetes which is consistent with a loss of insulin
production. Therefore, fasted state metabolic pathways would be highly active
contributing to hyperglycemia and ketogenesis. The other pathways listed would be
active in the fed state or when insulin is high.
Which of the following enzymes is correctly paired with its allosteric inhibitor?
Acetyl-CoA carboxylase: palmitoyl-CoA
The regulatory step in fatty acid synthesis is the synthesis of malonyl-CoA by acetyl-
CoA carboxylase. This enzyme can be inhibited by fatty acyl-CoA . Elevated fatty acyl-
CoA will also inhibit the tricarboxylate transporter and reduce citrate efflux from the
TCA.
A defect in the thioesterase subunit of fatty acid synthase would impair which of
the following activities of the enzyme complex?
Liberation of newly assembled palmitate from the enzyme
Fatty acid synthase is a multimeric enzyme and the final and sixth enzyme in the chain
is the thioesterase which will liberate the newly formed palmitate.
Under fasting conditions, acetyl-CoA carboxylase will be inhibited by an increase
in which of the following compounds?
fatty acyl-CoA
In fasting conditions when lipolysis is active, an increase in fatty acyl-CoA in the cell for
the process of β-oxidation will decrease citrate efflux from the mitochondria and activity
of acetyl-CoA carboxylase.
An increase in the ratio of insulin to glucagon will increase the activity of which
of the following enzymes (+ indicates activity is increased; - indicates activity is
not increased by insulin)?
