UNE Medical Biochemistry Final Exam
Questions With Correct Answers
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 |- |CORRECT |ANSWER✔✔-Hormone-sensitive |lipase
β- |oxidation |of |long-chain |fatty |acids |is |inhibited |by:
Pantothenic |Acid |(vitamin |B5)
Carnitine
Malonyl-CoA
Fatty |acids |- |CORRECT |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 |- |CORRECT |
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 |- |
CORRECT |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 |- |CORRECT |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 |- |CORRECT |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 |- |CORRECT |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 |- |CORRECT |ANSWER✔✔-Acetone
Questions With Correct Answers
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 |- |CORRECT |ANSWER✔✔-Hormone-sensitive |lipase
β- |oxidation |of |long-chain |fatty |acids |is |inhibited |by:
Pantothenic |Acid |(vitamin |B5)
Carnitine
Malonyl-CoA
Fatty |acids |- |CORRECT |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 |- |CORRECT |
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 |- |
CORRECT |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 |- |CORRECT |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 |- |CORRECT |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 |- |CORRECT |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 |- |CORRECT |ANSWER✔✔-Acetone
