Question 1

Which statement is NOT true about the anammox reaction?

Accepted Answer

A)   Anammox converts ammonia to nitrogen.
B)   Anammox is performed by symbiotic bacteria of leguminous plants.
C)   Anammox generates the highly reactive molecule hydrazine that is a component of rocket fuel.
D)   Anammox occursw anaerobically.
E)   The ultimate electron acceptor in anammox is nitrite.

Question 2

Which statement is TRUE about gout?

Accepted Answer

A)   Gout is caused by excessive breakdown of pyrimidine nucleotides.
B)   Gout can be treated by administration of fluorouracil.
C)   Gout is particularly prevalent in patients lacking xanthine oxidase.
D)   Gout leads to deposition of sodium urate crystals in the joints.
E)   Eating more liver is an effective way to treat the symptoms of gout.

Question 3

What high-energy structure is found as part of the major intermediate in the glutamine synthetase reaction?

Accepted Answer

A)   a phosphoanhydride bond
B)   a phosphoester
C)   an acyl phosphate
D)   an enol
E)   a thioester

Question 4

If acetyl-CoA containing radiolabeled carbons in the acetyl group was used to synthesize leucine, where would the radioactive carbons be found?

Accepted Answer

Leucine is an essential amino acid that ...

Question 5

Phosphocreatine is derived from which amino acid?

Accepted Answer

A)   alanine
B)   arginine
C)   cysteine
D)   serine
E)   lysine

Question 6

The synthesis of purine and pyrimidine nucleotides differ in that:

Accepted Answer

A)   ATP is required in the synthesis of purines but not in the synthesis of pyrimidines.
B)   purine biosynthesis starts with the formation of PRPP, whereas pyrimidines incorporate the PRPP near the end of the pathway.
C)   purine formation requires a THF derivative, whereas pyrimidine formation does not.
D)   pyrimidine biosynthesis is tightly regulated in the cell, whereas purine biosynthesis is not.
E)   pyrimidines go through many steps, adding a single carbon or nitrogen each time, whereas the basic skeleton for purines is formed by two main precursors.

Question 7

Draw the structure of deoxythymidylic acid (dTMP). Indicate the source of each N and each C in the thymine ring, including its substituents.

Accepted Answer

Deoxythymidylic acid (dTMP) is a nucleot...

Question 8

The amino acid _____ and is an intermediate in the biosynthesis of _____.

Accepted Answer

A)   histidine; purines
B)   glycine; heme
C)   serine; heme
D)   serine; sphingosine
E)   glutamine; glutathione

Question 9

Describe the pathway by which GMP is converted into GTP; show the co-substrates that are involved and name the enzymes.

Accepted Answer

The conversion of GMP (guanosine monopho...

Question 10

Draw the structure of 5'AMP. What is the first "committed" step in the biosynthetic sequence that leads to 5'AMP? How is this step regulated?

Accepted Answer

5'AMP, or 5' adenosine monophosphate, is...

Question 11

Homoserine is:

Accepted Answer

A)   a precursor of both methionine and threonine.
B)   a precursor of serine.
C)   derived from homocysteine.
D)   derived from serine.
E)   derived from threonine.

Question 12

Show the reaction catalyzed by thymidylate synthase and explain with a simple diagram how the chemotherapeutic agents fluorouracil and methotrexate inhibit the synthesis of dTMP.

Accepted Answer

Thymidylate synthase is an enzyme that c...

Question 13

L-Dopa is an intermediate in the conversion of:

Accepted Answer

A)   phenylalanine to homogentisic acid.
B)   phenylalanine to tyrosine.
C)   tyrosine to epinephrine.
D)   tyrosine to phenylalanine.
E)   tyrosine to phenylpyruvate.

Question 14

An amino acid that does NOT derive its carbon skeleton, at least in part, from oxaloacetate is:

Accepted Answer

A)   aspartate.
B)   lysine.
C)   methionine.
D)   proline.
E)   threonine.

Question 15

Trace the path of nitrogen from atmospheric N2 into glutamate. Name the intermediates (no structures necessary) and enzymes, and show any coenzymes involved.

Accepted Answer

The path of nitrogen from atmospheric N ...

Question 16

Give the overall reaction that results from the combined action of glutamate synthase and glutamine synthetase.

Accepted Answer

Glutamate synthase and glutamine synthet...

Question 17

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H4 folate) , it would probably be deficient in the biosynthesis of:

Accepted Answer

A)   isoleucine.
B)   leucine.
C)   lysine.
D)   methionine.
E)   serine.

Question 18

Glutamine is a nitrogen donor in the synthesis of:

Accepted Answer

A)   CTP.
B)   dTTP.
C)   inosinic acid (IMP) .
D)   orotate.
E)   UMP.

Question 19

An intermediate of purine degradation in humans is:

Accepted Answer

A)   glutamate.
B)   NH4+.
C)   succinate.
D)   urea.
E)   uric acid.

Question 20

Which molecule does NOT require 5-phosphoribosyl-1-pyrophosphate (PRPP)  as a substrate for biosynthesis?

Accepted Answer

A)   adenosine monophosphate
B)   cytidine monophosphate
C)   guanosine monophosphate
D)   histidine
E)   All of these molecules require PRPP for biosynthetic pathways.

Exam 22: Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Draw the structure of deoxythymidylic acid (dTMP). Indicate the source of each N and each C in the thymine ring, including its substituents.

Correct AnswerAnswered by ExamLex AIDeoxythymidylic acid (dTMP) is a nucleot...View AnswerShow Answer

Give the overall reaction that results from the combined action of glutamate synthase and glutamine synthetase.

Correct AnswerAnswered by ExamLex AIGlutamate synthase and glutamine synthet...View AnswerShow Answer

What high-energy structure is found as part of the major intermediate in the glutamine synthetase reaction?

Correct AnswerverifiedShow Answer

Draw the structure of 5'AMP. What is the first "committed" step in the biosynthetic sequence that leads to 5'AMP? How is this step regulated?

Correct AnswerAnswered by ExamLex AI5'AMP, or 5' adenosine monophosphate, is...View AnswerShow Answer

Which statement is NOT true about the anammox reaction?

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Phosphocreatine is derived from which amino acid?

Correct AnswerverifiedShow Answer

Show the reaction catalyzed by thymidylate synthase and explain with a simple diagram how the chemotherapeutic agents fluorouracil and methotrexate inhibit the synthesis of dTMP.

Correct AnswerAnswered by ExamLex AIThymidylate synthase is an enzyme that c...View AnswerShow Answer

An amino acid that does NOT derive its carbon skeleton, at least in part, from oxaloacetate is:

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Describe the pathway by which GMP is converted into GTP; show the co-substrates that are involved and name the enzymes.

Correct AnswerAnswered by ExamLex AIThe conversion of GMP (guanosine monopho...View AnswerShow Answer

If a cell were unable to synthesize or obtain tetrahydrofolic acid (H4 folate) , it would probably be deficient in the biosynthesis of:

Correct AnswerverifiedShow Answer

The amino acid _____ and is an intermediate in the biosynthesis of _____.

Correct AnswerverifiedShow Answer

The synthesis of purine and pyrimidine nucleotides differ in that:

Correct AnswerverifiedShow Answer

Glutamine is a nitrogen donor in the synthesis of:

Correct AnswerverifiedShow Answer

Homoserine is:

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Which molecule does NOT require 5-phosphoribosyl-1-pyrophosphate (PRPP) as a substrate for biosynthesis?

Correct AnswerverifiedShow Answer

Trace the path of nitrogen from atmospheric N2 into glutamate. Name the intermediates (no structures necessary) and enzymes, and show any coenzymes involved.

Correct AnswerAnswered by ExamLex AIThe path of nitrogen from atmospheric N ...View AnswerShow Answer

L-Dopa is an intermediate in the conversion of:

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Which statement is TRUE about gout?

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An intermediate of purine degradation in humans is:

Correct AnswerverifiedShow Answer

If acetyl-CoA containing radiolabeled carbons in the acetyl group was used to synthesize leucine, where would the radioactive carbons be found?

Correct AnswerAnswered by ExamLex AILeucine is an essential amino acid that ...View AnswerShow Answer

Correct Answer
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Deoxythymidylic acid (dTMP) is a nucleot...
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Glutamate synthase and glutamine synthet...
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5'AMP, or 5' adenosine monophosphate, is...
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Thymidylate synthase is an enzyme that c...
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The conversion of GMP (guanosine monopho...
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If a cell were unable to synthesize or obtain tetrahydrofolic acid (H₄ folate) , it would probably be deficient in the biosynthesis of:

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The amino acid _ and is an intermediate in the biosynthesis of _.

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Trace the path of nitrogen from atmospheric N₂ into glutamate. Name the intermediates (no structures necessary) and enzymes, and show any coenzymes involved.

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The path of nitrogen from atmospheric N ...
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Leucine is an essential amino acid that ...
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