Question 1

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

Accepted Answer

@#LAT-DLM&-Ketoglutarate + NH₄

Question 2

Match the signaling molecule with its amino acid precursor (a given precursor may be used more than once or not at all):
-

Accepted Answer

(a)-(4);
 (b)-(3);

Question 3

Describe two types of regulation of the enzyme glutamine synthetase and explain why the regulation of this enzyme is so complex.

Accepted Answer

(1)The enzyme is subject to cumulative a

Question 4

The nitrogen atom in the side chain of lysine is derived from which amino acid?

Accepted Answer

A) Aspartic acid 
B) Glutamic acid 
C) Glutamine 
D) Asparagine 
E) Arginine 
A) Aspartic acid 
B) Glutamic acid 
C) Glutamine 
D) Asparagine 
E) Arginine

Question 5

Glutamine is a nitrogen donor in the synthesis of:

Accepted Answer

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

Question 6

Draw the structure of 5'-UMP (uridylic acid).Circle those carbon atoms donated by atoms derived from aspartate.

Accepted Answer

The structure of UMP is shown in ,which

Question 7

The enzymatic machinery to fix atmospheric N2 into NH4+ is:

Accepted Answer

A) a means of producing ATP when excess N2 is available. 
B) composed of two key proteins,each containing iron. 
C) relatively stable when exposed to O2. 
D) specific to plant cells. 
E) unaffected by the supply of electrons. 
A) a means of producing ATP when excess N2 is available. 
B) composed of two key proteins,each containing iron. 
C) relatively stable when exposed to O2. 
D) specific to plant cells. 
E) unaffected by the supply of electrons.

Question 8

If glucose labeled with 14C at C-1 were the starting material for amino acid biosynthesis,the product(s)that would be readily formed is (are):

Accepted Answer

A) serine labeled at the carboxyl carbon. 
B) serine labeled at alpha carbon. 
C) serine labeled at the R-group carbon. 
D) All of the above 
E) None of the above 
A) serine labeled at the carboxyl carbon. 
B) serine labeled at alpha carbon. 
C) serine labeled at the R-group carbon. 
D) All of the above 
E) None of the above

Question 9

Diagram the biosynthetic pathway from UMP to dTTP.Use abbreviations (e.g. ,UMP),not complete structures,and indicate where any co-substrates participate.

Accepted Answer

UMP + ATP @#LAT-DLM& UDP + ADP (nucleoside monopho

Question 10

Show how you can form $\delta$-aminolevulinate from either glycine and succinyl-CoA or from glutamate.

Accepted Answer

In most animals,glycine and succinyl-CoA

Question 11

A cell that is unable to synthesize or obtain tetrahydrofolic acid (H4 folate)would probably be deficient in the biosynthesis of:

Accepted Answer

A) CMP. 
B) GMP. 
C) orotate. 
D) thymidylate (TMP). 
E) UMP. 
A) CMP. 
B) GMP. 
C) orotate. 
D) thymidylate (TMP). 
E) UMP.

Question 12

An animal cell is capable of converting alanine into serine.What is the shortest pathway using known enzymes by which this conversion could be accomplished? Show intermediates and cofactors;no enzyme names are required.(Hint: The first step is removal of the nitrogen by transamination. )

Accepted Answer

(1)Alanine @#LAT-DLM& pyruvate
(2)Pyruvate + HCO<s

Question 13

Glutamine,arginine,and proline:

Accepted Answer

A) do not have a common precursor. 
B) may all be derived from a citric acid cycle intermediate. 
C) may all be derived from a Cori cycle intermediate. 
D) may all be derived from a glycolytic intermediate. 
E) may all be derived from a urea cycle intermediate. 
A) do not have a common precursor. 
B) may all be derived from a citric acid cycle intermediate. 
C) may all be derived from a Cori cycle intermediate. 
D) may all be derived from a glycolytic intermediate. 
E) may all be derived from a urea cycle intermediate.

Question 14

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. 
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 15

In bacteria,the amino acids listed below can be derived directly or indirectly from serine,alanine,aspartate,glutamate,or chorismate.Indicate below which of these "parent" compounds provides the carbon skeleton for each amino acid:
Parent compound
Asparagine __________________
Tryptophan __________________
Glycine __________________
Methionine __________________
Threonine __________________
Cysteine __________________
Proline __________________
Isoleucine __________________
Phenylalanine __________________

Accepted Answer

Aspartate (asparagine)
chorismate (trypt

Question 16

The plant hormone indole-3-acetate (auxin)is formed from:

Accepted Answer

A) arginine. 
B) histidine. 
C) phenylalanine. 
D) threonine. 
E) tryptophan. 
A) arginine. 
B) histidine. 
C) phenylalanine. 
D) threonine. 
E) tryptophan.

Question 17

Which one of the following statements correctly describes the biosynthetic pathway for purine nucleotides?

Accepted Answer

A) Purine deoxynucleotides are made by the same path as ribonucleotides,followed by reduction of the ribose moiety. 
B) The first enzyme in the path is aspartate transcarbamoylase (ATCase). 
C) The nitrogen in the purine base that is bonded to ribose in the nucleotide is derived originally from glycine. 
D) The pathway occurs only in plants and bacteria,not in animals. 
E) The purine rings are first synthesized,then condensed with ribose phosphate. 
A) Purine deoxynucleotides are made by the same path as ribonucleotides,followed by reduction of the ribose moiety. 
B) The first enzyme in the path is aspartate transcarbamoylase (ATCase). 
C) The nitrogen in the purine base that is bonded to ribose in the nucleotide is derived originally from glycine. 
D) The pathway occurs only in plants and bacteria,not in animals. 
E) The purine rings are first synthesized,then condensed with ribose phosphate.

Question 18

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. 
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 19

Glutamine synthetase converts _____ to _____ whereas glutamate synthase converts ____ to _____.

Accepted Answer

A) formate;glutamine;ammonia;glutamate 
B) asparagine;glutamine;$\alpha$-ketoglutarate;glutamate 
C) ($\alpha$-ketoglutarate;glutamine;oxaloacetic acid;glutamate) 
D) ($\alpha$-ketoglutarate;glutamine;$\alpha$-ketoglutarate;glutamate) 
E) glutamate;glutamine;$\alpha$-ketoglutarate;glutamate 
A) formate;glutamine;ammonia;glutamate 
B) asparagine;glutamine;$\alpha$-ketoglutarate;glutamate 
C) ($\alpha$-ketoglutarate;glutamine;oxaloacetic acid;glutamate) 
D) ($\alpha$-ketoglutarate;glutamine;$\alpha$-ketoglutarate;glutamate) 
E) glutamate;glutamine;$\alpha$-ketoglutarate;glutamate

Question 20

Show the steps by which an intermediate of glycolysis can be converted into serine.

Accepted Answer

Serine is derived from 3-phosp

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

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

Match the signaling molecule with its amino acid precursor (a given precursor may be used more than once or not at all): -

Describe two types of regulation of the enzyme glutamine synthetase and explain why the regulation of this enzyme is so complex.

The nitrogen atom in the side chain of lysine is derived from which amino acid?

Glutamine is a nitrogen donor in the synthesis of:

Draw the structure of 5'-UMP (uridylic acid).Circle those carbon atoms donated by atoms derived from aspartate.

The enzymatic machinery to fix atmospheric N2 into NH4+ is:

If glucose labeled with 14C at C-1 were the starting material for amino acid biosynthesis,the product(s)that would be readily formed is (are):

Diagram the biosynthetic pathway from UMP to dTTP.Use abbreviations (e.g. ,UMP),not complete structures,and indicate where any co-substrates participate.

Show how you can form δ\deltaδ -aminolevulinate from either glycine and succinyl-CoA or from glutamate.

A cell that is unable to synthesize or obtain tetrahydrofolic acid (H4 folate)would probably be deficient in the biosynthesis of:

An animal cell is capable of converting alanine into serine.What is the shortest pathway using known enzymes by which this conversion could be accomplished? Show intermediates and cofactors;no enzyme names are required.(Hint: The first step is removal of the nitrogen by transamination. )

Glutamine,arginine,and proline:

Homoserine is:

The plant hormone indole-3-acetate (auxin)is formed from:

Which one of the following statements correctly describes the biosynthetic pathway for purine nucleotides?

The synthesis of purine and pyrimidine nucleotides differ in that:

Glutamine synthetase converts _____ to _____ whereas glutamate synthase converts ____ to _____.

Show the steps by which an intermediate of glycolysis can be converted into serine.

The Foundations of Biochemistry

Water

Amino Acids, peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

Glycolysis, gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

The enzymatic machinery to fix atmospheric N₂ into NH₄⁺ is:

If glucose labeled with ¹⁴C at C-1 were the starting material for amino acid biosynthesis,the product(s)that would be readily formed is (are):

Show how you can form $\delta$ -aminolevulinate from either glycine and succinyl-CoA or from glutamate.

A cell that is unable to synthesize or obtain tetrahydrofolic acid (H₄ folate)would probably be deficient in the biosynthesis of:

Glutamine synthetase converts ___ to _ whereas glutamate synthase converts to ___.