Final Exam: Cumulative

Front 1

The major regulated step of the urea cycle is which one of the following?

Back 1

carbonyl phosphate synthetase I

Hint 1

A. carbonyl phosphate synthetase I

B. argininosuccinate synthetase

C. arginase

D. ornitnine transcarbamoylase

E. arginonosuccinate lyase

Front 2

Which of the following forms of tetrahydrofulate is required for the synthesis of methionine from homocysteine?

Back 2

N5-methyl tetrahydrofolate

Hint 2

A. N5, N10-methylene tetrahydrofolate

B. N5-formimino tetrahydrofolate

C. N5, N10-methenyl tetrahydrofolate

E. N10-formyl tetrahydrofolate

Front 3

A dietary vitamin B12 deficiency can result from which of the following?

Back 3

pancreatic insufficiency

Hint 3

A. eating a diet that's high in animal protein

B. increased absorption of folic acid

C. excessive intrinsic factor production by the gastric parietal cells

D. pancreatic insufficiency

E. inability to conjugate the vitamin with glutamic acid

Front 4

Pyroxidal phosphate, which is required for transaminations, is also required for for which of the follwoing pathways?

Back 4

glycogenolysis

Hint 4

A. glycolysis

B. glycogenolysis

C. the TCA cycle

D. fatty acid oxidation

E. gluconeogenesis

Front 5

Which one of the following enzymes can fix ammonia into an organic molecule?

Back 5

glutamate dehydrogenase

Hint 5

A. alanine-pyruvate amino transferase

B. arginase

C. glutaminase

D. glutamate dehydrogenase

E. arginosuccinate synthetase

Front 6

Pyridoxal phosphate is required for which of the following reaction pathways or individual reactions?

Back 6

methionine -> cysteine + alpha-ketobutyrate

Hint 6

A. methionine -> cysteine + alpha-ketobutyrate

B. phenylalanine -> tyrosine

C. pyruvate -> acetyl-CoA

D. glucose -> glycogen

E. propionyl-CoA -> succinyl-CoA

Front 7

Propionic acid accumulation from amino acid degredation will result from a deficiency in which of the following vitamins?

Back 7

bitotin

Hint 7

A. vitamin B6

B. vitamin B1

C. folic acid

D. biotin

E. vitamin B12

F. vitamin B2

Front 8

A newborn infant has elevated levels of phenylalanine and ohenylpyruvate in her blood. Which of the following enzymes might be deficient in this baby?

Back 8

dihydropteridine reductase

Hint 8

A. dihydrofolate reductase

B. phenylalanine oxidase

C. phenylalanine dehydrogenase

D. tyrosine hydroxylase

E. dihydropteridine reductase

Front 9

If an individual has a vitamin 6 deficiency, which of the following amino acids could still be synthesized and be considered non-essential?

Back 9

tyrosine

Hint 9

A. serine

B. tyrosine

C. alanine

D. cysteine

E. aspartate

Front 10

The nitrogens in urea are derived directly from which ofthe following compounds?

Back 10

Carbamoyl phosphate and aspartate

Hint 10

A. Ornithine and carbamoyl phosphate

B. Ornithine and aspartate

C. Ornithine and glutamate

D. Carbamoyl phosphate and aspartate

E. Carbamoyl phosphate and glutamine

F. Aspartate and glutamine

Front 11

Which one of the following enzymes can fix ammonia into an organic molecule?

Back 11

Glutamate dehydrogenase

Hint 11

A. Alanine–pyruvate aminotransferase

B. Glutaminase

C. Glutamate dehydrogenase

D. Arginase

E. Argininosuccinate synthetase

Front 12

Pyridoxal phosphate, which is required for transaminations,is also required for which of the following pathways?

Back 12

Glycogenolysis

Hint 12

A. Glycolysis

B. Gluconeogenesis

C. Glycogenolysis

D. The TCA cycle

E. Fatty acid oxidation

Front 13

The major regulated step of the urea cycle is which one ofthe following?

Back 13

Carbamoyl phosphate synthetase I

Hint 13

A. Carbamoyl phosphate synthetase I

B. Ornithine transcarbamoylase

C. Argininosuccinate synthetase

D. Argininosuccinate lyase

E. Arginase

Front 14

If an individual has a vitamin B6 deficiency, which of the following amino acids could still be synthesized and be considered nonessential?

Back 14

Tyrosine

Hint 14

A. Tyrosine

B. Serine

C. Alanine

D. Cysteine

E. Aspartate

Front 15

The degradation of amino acids can be classified into families, which are named after the end product of the degradative pathway. Which of the following is such an end product?

Back 15

Succinyl-CoA

Hint 15

A. Citrate

B. Glyceraldehyde 3-phosphate

C. Fructose 6-phosphate

D. Malate

E. Succinyl-CoA

Front 16

A newborn infant has elevated levels of phenylalanine and phenylpyruvate in her blood. Which of the following enzymes might be deficient in this baby?

Back 16

Dihydropteridine reductase

Hint 16

A. Phenylalanine dehydrogenase

B. Phenylalanine oxidase

C. Dihydropteridine reductase

D. Tyrosine hydroxylase

E. Tetrahydrofolate synthase

Front 17

Pyridoxal phosphate is required for which of the following pathways or individual reactions?

Back 17

Methionine → cysteine -ketobutyrate

Hint 17

A. Phenylalanine → tyrosine

B. Methionine → cysteine -ketobutyrate

C. Propionyl-CoA → succinyl-CoA

D. Pyruvate → acetyl-CoA

E. Glucose → glycogen

Front 18

A folic acid deficiency would interfere with the synthesis of which of the following amino acids from the indicated precursors?

Back 18

Glycine from glucose and alanine

Hint 18

A. Aspartate from oxaloacetate and glutamate

B. Glutamate from glucose and ammonia

C. Glycine from glucose and alanine

D. Proline from glutamate

E. Serine from glucose and alanine

Front 19

Which of the following reactions requires N 5,N10-methylene-FH4 as a carbon donor?

Back 19

Betaine to dimethylglycine

Hint 19

A. Homocysteine to methionine

B. Serine to glycine

C. Betaine to dimethylglycine

D. dUMP to dTMP

E. The de novo biosynthesis of the purine ring

Front 20

Propionic acid accumulation from amino acid degradation will result from a deficiency of which of the following vitamins?

Back 20

Biotin

Hint 20

A. Vitamin B6

B. Biotin

C. Folic acid

D. Vitamin B12

E. Vitamin B1

F. Vitamin B2

Front 21

A dietary vitamin B12 deficiency can result from which of the following?

Back 21

Pancreatic insufficiency

Hint 21

A. Excessive intrinsic factor production by the gastric parietal cells

B. Eating a diet that is high in animal protein

C. Pancreatic insufficiency

D. Increased absorption of folic acid

E. Inability to conjugate the vitamin with glutamic acid

Front 22

Which of the following forms of tetrahydrofolate is required for the synthesis of methionine from homocysteine?

Back 22

N5-methyl tetrahydrofolate

Hint 22

A. N5,N10-methylene tetrahydrofolate

B. N5-methyl tetrahydrofolate

C. N5,N10-methenyl tetrahydrofolate

D. N10-formyl tetrahydrofolate

E. N 5-formimino tetrahydrofolate

Front 23

An alternative method to methylate homocysteine to form methionine is which of the following?

Back 23

Using betaine as the methyl donor

Hint 23

A. Using glycine and FH4 as the methyl donor

B. Using dimethylglycine as the methyl donor

C. Using choline as the methyl donor

D. Using sarcosine as the methyl donor

E. Using betaine as the methyl donor

Front 24

Similarities between carbamoyl phosphate synthetase I and carbamoyl phosphate synthetase II include which one ofthe following?

Back 24

Carbon source

Hint 24

A. Carbon source

B. Intracellular location

C. Nitrogen source

D. Regulation by N-acetyl glutamate

E. Regulation by UMP

Front 25

Gout can result from a reduction in activity of which one of the following enzymes?

Back 25

Glucose 6-phosphatase

Hint 25

A. Glutamine phosphoribosyl amidotransferase

B. Glucose 6-phosphatase

C. Glucose-6-phosphate dehydrogenase

D. PRPP synthetase

E. Purine nucleoside phosphorylase

Front 26

Lesch–Nyhan syndrome is due to an inability to catalyze which of the following reactions?

Back 26

Guanine to GMP

Hint 26

A. Adenine to AMP

B. Adenosine to AMP

C. Guanine to GMP

D. Guanosine to GMP

E. Thymine to TMP

F. Thymidine to TMP

Front 27

Allopurinol can be used to treat gout because of its ability to inhibit which one of the following reactions?

Back 27

Xanthine to uric acid

Hint 27

A. AMP to XMP

B. Xanthine to uric acid

C. Inosine to hypoxanthine

D. IMP to XMP

E. XMP to GMP

Front 28

The regulation of ribonucleotide reductase is quite complex.Assuming that an enzyme deficiency leads to highly elevated levels of dGTP, what effect would you predict on the reduction of ribonucleotides to deoxyribonucleotides under these conditions?

Back 28

The formation of dADP will be favored.

Hint 28

A. Elevated levels of dCDP will be produced.

B. The formation of dADP will be favored.

C. AMP will begin to be reduced.

D. Reduced thioredoxin will become rate-limiting, thereby reducing the activity of ribonucleotide reductase.

E. Deoxy-GTP will bind to the overall activity site and inhibit the functioning of the enzyme.

Front 29

ADD A PICTURE

Which of the profiles indicated in the following would occur within 2 hours after eating a meal that was very high in protein and low in carbohydrates?

Back 29

D.

Front 30

The gut uses glutamine as an energy source, but it can also secrete citrulline, synthesized from the carbons of glutamine. Which of the following compounds is an obligatory intermediate in this conversion (consider only the carbon atoms of glutamine while answering this question)?

Back 30

Glutamate

Hint 30

A. Aspartate

B. Succinyl-CoA

C. Glutamate

D. Serine

E. Fumarate

Front 31

The signal that indicates to muscle that protein degradation needs to be initiated is which of the following?

Back 31

Cortisol

Hint 31

A. Insulin

B. Glucagon

C. Epinephrine

D. Cortisol

E. Glucose

Front 32

The skeletal muscles convert branched-chain amino acid(BCAA) carbons to glutamine for export to the rest of the body. An obligatory intermediate, which carries carbons originally from the BCAAs, in the conversion of BCAAs to glutamine, is which of the following?

Back 32

Isocitrate

Hint 32

A. Urea

B. Pyruvate

C. Lactate

D. Isocitrate

E. Phosphoenolpyruvate

Front 33

ADD PICTURE

An individual in sepsis will display which of the following metabolic patterns?

Back 33

C

Front 34

Amajor fuel source for muscle cells during the postabsorptive state is what?

Back 34

Leucine

Hint 34

A. Glutamine

B. Alanine

C. Leucine

D. Methionine

E. Tryptophan

Front 35

Howdoes sodium benzoate help resolve hyperammonemias?

Back 35

It promotes the production of glycine

Hint 35

A. Itpromotes the production of glycine

B. Itinhibits carbamoyl phosphate synthetase I

C. Itturns on the fetal urea cycle genes

D. Itpromotes the formation of arginine

E. Itinhibits ornithine transcarbamoylase

Front 36

Thesynthesis of which molecule directly requires SAM?

Back 36

Epinephrine

Hint 36

A. Tyrosine

B. Epinephrine

C. Dopamine

D. Norepinephrine

E. L-dopa

Front 37

Inthe postabsorptive state which amino acids are consumed by the brain for theproduction of glutamine?

Back 37

Isoleucine and Valine

Hint 37

A. Isoleucineand Valine

B. Phenylalanineand Tyrosine

C. Glycineand Glutamate

D. Alanineand Cysteine

E. Serineand Threonine

Front 38

Whichamino acid is purely ketogenic?

Back 38

leucine

Hint 38

A. Isoleucine

B. Leucine

C. Threonine

D. Valine

E. Arginine

Front 39

Whattype of molecule serves as a substrate for thymidylate synthase?

Back 39

Deoxyribonucleotide

Hint 39

A. Purinebase

B. Deoxyribonucleotide

C. Ribonucleoside

D. Deoxyribonucleoside

E. Pyrimidinebase

Front 40

Inresponse to epinephrine, which of the following occurs?

Back 40

Muscle pyruvate kinase is active,liver enzyme is inhibited

Hint 40

A. MuscleACC is activated by phosphorylation, whereas liver enzyme is inhibited byphosphorylation

B. Muscleand liver PFK-2/F2,6BPase are active as a kinase

C. Muscleglycogen phosphorylase is active, liver enzyme is inhibited

D. Musclepyruvate kinase is active, liver enzyme is inhibited E. Muscleadenylate cyclase is active, liver enzyme is inhibited

Front 41

Whichsubstrates are needed to make alanine during transamination?

Back 41

Glutamateand Pyruvate

Hint 41

A. α-ketoglutarate and Oxaloacetate

B. Glutamateand Pyruvate

C. α-ketoglutarate and Pyruvate

D. Glutamateand Oxaloacetate E. Glutamateand α-ketoglutarate

Front 42

Underwhich conditions is glutamine used as a major fuel source by the kidney?

Back 42

In an acidotic state

Hint 42

A. Ina postprandial state

B. Ina postabsorptive state

C. Ina fasted state

D. Inan acidotic state

E. Ina hyperglycemic state

Front 43

Whatproperty of glutamine synthetase found in the perivenous hepatocytes isappropriate for the function of these cells?

Back 43

It has a low Km for NH4+.

Hint 43

A. Ithas a low Km for NH4+.

B. Ithas a low Km for glutamate. C. Ithas a high Km for NH4+.

D. Ithas a high Vmax.

E. Ithas a high Km for glutamate.