Nucleotide Biosynthesis Quiz
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Nucleotide Biosynthesis Quiz

Test your knowledge of nucleotide biosynthesis with this quiz. Explore the activated precursors of nucleic acids, their role in genome replication, transcription, and energy production, as well as their function as phosphoryl group donors and allosteric effectors.

Created by
@BlamelessJustice

Questions and Answers

Which molecule is consumed to ensure irreversibility in the intramolecular reaction in which the nucleophile and phosphate-activated carbon atom AIR synthetase (FGAM cyclase)?

ATP

What is the potent inhibitor of CTP and GMP synthetases that partially inhibits FGAM synthetase?

Acivicin

Which enzyme catalyzes the removal of fumarate from 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide in the synthesis of inosinate?

Adenylsuccinate synthase

What is the hydrogen acceptor in the oxidation of inosinate to xanthylate?

<p>NAD+</p> Signup and view all the answers

What is the reciprocal use of nucleotides by the pathways an important regulatory opportunity for?

<p>Regulation of purine synthesis</p> Signup and view all the answers

What is the final intermediate formed by the addition of a formyl group from N10-formyltetrahydrofolate to a nitrogen atom?

<p>Carboxyaminoimidazole ribonucleotide</p> Signup and view all the answers

What is the potent, reversible, uncompetitive inhibitor of inosine monophosphate dehydrogenase used successfully in preventing graft rejection?

<p>Mycophenolic acid</p> Signup and view all the answers

What does mycophenolic acid block in the de novo pathway of purine synthesis?

<p>Formation of GMP</p> Signup and view all the answers

What is the final carbon contributed by in the synthesis of the second fused ring of the purine nucleus?

<p>N10-formyltetrahydrofolate</p> Signup and view all the answers

What is the molecule required for the substitution of NH3 for the c=0 oxygen atom at C-6 in the synthesis of adenylate from inosinate?

<p>GTP</p> Signup and view all the answers

Which nucleotide is required for capping of mRNA?

<p>GTP</p> Signup and view all the answers

What is the precursor for the formation of tetrahydrobiopterin, required for hydroxylation reactions and nitric oxide generation?

<p>GTP</p> Signup and view all the answers

Which nucleotide is important in the control of coronary blood flow?

<p>ATP</p> Signup and view all the answers

Which nucleotide is required for the synthesis of sulfated biomolecules such as proteoglycans and sulfatides?

<p>UTP</p> Signup and view all the answers

In which type of cells do adenine nucleotides far exceed the concentrations of guanine, cytosine, and uridine nucleotides?

<p>Red blood cells</p> Signup and view all the answers

What is the ratio whose alteration depends on the energy state of the cell?

<p>ATP/(ATP + ADP + AMP)</p> Signup and view all the answers

Which class of pathways leads to the synthesis of deoxyribonucleotides from the corresponding ribonucleotides?

<p>De novo pathways</p> Signup and view all the answers

What do coenzymes NAD+, NADP+, FAD, and coenzyme A contain as part of their structures?

<p>5-AMP moiety</p> Signup and view all the answers

What is the activated intermediate that participates in biosynthetic processes such as glycogen synthesis?

<p>UDP-glucose</p> Signup and view all the answers

Which nucleotide predominates in hypoxic cells?

<p>NDP</p> Signup and view all the answers

Which enzyme catalyzes the conversion of phosphoribosyl pyrophosphate (PRPP) to 5-phosphoribosylamine, the committed step in purine biosynthesis?

<p>Glutamine phosphoribosyl amidotransferase</p> Signup and view all the answers

Which enzyme is responsible for the activation of the glycine carboxyl group by consuming ATP in the purine biosynthesis pathway?

<p>Glycinamide ribonucleotide synthetase</p> Signup and view all the answers

Which enzyme catalyzes the formation of N-glycosidic bond of the purine nucleotide in the purine biosynthesis pathway?

<p>Glutamine phosphoribosyl amidotransferase</p> Signup and view all the answers

Which enzyme is expressed for longer in individuals with Down Syndrome?

<p>Glycinamide ribonucleotide synthetase</p> Signup and view all the answers

Which enzyme is responsible for transferring the formyl group from N10-formyltetrahydrofolate to glycine in the purine biosynthesis pathway?

<p>Gar transformylase</p> Signup and view all the answers

Which enzyme is involved in the synthesis of tetrahydrofolate, a carrier of activated one-carbon units?

<p>Gar transformylase</p> Signup and view all the answers

Which enzyme catalyzes the conversion of dihydrofolate to tetrahydrofolate in mammals?

<p>Dihydrofolate reductase</p> Signup and view all the answers

Which compound is an analog of glutamine and a purine antagonist with antineoplastic properties?

<p>Azaserine</p> Signup and view all the answers

Which drug inhibits bacterial dihydrofolate reductase and has potent antibacterial activity?

<p>Trimethoprim</p> Signup and view all the answers

Which drug is a structural analog of folic acid and is used to control the spread of cancer by interfering with nucleotides for DNA and RNA?

<p>Methotrexate</p> Signup and view all the answers

Which of the following is true about nucleotide biosynthesis?

<p>Nucleotides are essential components of signal-transduction pathways.</p> Signup and view all the answers

What is the precursor for the formation of the cofactor tetrahydrobiopterin?

<p>GTP</p> Signup and view all the answers

In which type of cells do adenine nucleotides far exceed the concentrations of guanine, cytosine, and uridine nucleotides?

<p>Red blood cells</p> Signup and view all the answers

What is the ratio altered depending on the energy state of the cell?

<p>ATP/(ATP + ADP + AMP)</p> Signup and view all the answers

Which class do nucleotides fall into, leading to the synthesis of ribonucleotides?

<p>Both de novo and salvage pathways</p> Signup and view all the answers

What is the activated precursor of nucleic acids necessary for the replication of the genome?

<p>Nucleotides</p> Signup and view all the answers

Which nucleotide is important in the control of coronary blood flow?

<p>Adenosine</p> Signup and view all the answers

What is the methyl donor in the formation of phosphatidylcholine from phosphatidylethanolamine?

<p>S-adenosylmethionine (SAM)</p> Signup and view all the answers

What is the sulfate donor to generate sulfated biomolecules such as proteoglycans and sulfatides?

<p>3-phosphoadenosine 5-phosphosulfate (PAPS)</p> Signup and view all the answers

What do coenzymes NAD+, NADP+, FAD and their reduced forms all contain as part of their structures?

<p>A 5 AMP moiety</p> Signup and view all the answers

Which enzyme catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate (PRPP) to 5-phosphoribosylamine, the committed step in purine biosynthesis?

<p>Phosphoribosyl pyrophosphate amidotransferase</p> Signup and view all the answers

Which molecule is consumed to ensure irreversibility in the intramolecular reaction in which the nucleophile and phosphate-activated carbon atom AIR synthetase (FGAM cyclase)?

<p>ATP</p> Signup and view all the answers

What is the final intermediate formed by the addition of a formyl group from N10-formyltetrahydrofolate to a nitrogen atom?

<p>N-Formylglycinamidine ribonucleotide (FGAM)</p> Signup and view all the answers

Which enzyme catalyzes the conversion of dihydrofolate to tetrahydrofolate in mammals?

<p>Dihydrofolate reductase</p> Signup and view all the answers

Which enzyme is responsible for transferring the formyl group from N10-formyltetrahydrofolate to glycine in the purine biosynthesis pathway?

<p>Glycinamide ribonucleotide transformylase</p> Signup and view all the answers

What is the potent inhibitor of CTP and GMP synthetases that partially inhibits FGAM synthetase?

<p>Mycophenolic acid</p> Signup and view all the answers

What is the activated precursor of nucleic acids necessary for the replication of the genome?

<p>PRPP</p> Signup and view all the answers

Which enzyme catalyzes the removal of fumarate from 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide in the synthesis of inosinate?

<p>Adenylosuccinate lyase</p> Signup and view all the answers

Which enzyme catalyzes the formation of N-glycosidic bond of the purine nucleotide in the purine biosynthesis pathway?

<p>Hypoxanthine-guanine phosphoribosyltransferase</p> Signup and view all the answers

Which molecule is the common precursor for AMP and GMP in purine biosynthesis?

<p>Inosine 5’-monophosphate (IMP)</p> Signup and view all the answers

How many moles of ATP are utilized per mole of IMP synthesized in purine nucleotide synthesis?

<p>6 moles</p> Signup and view all the answers

Where are all enzymes involved in the synthesis of purine nucleotides found?

<p>Cytosol</p> Signup and view all the answers

Which condition can result from mutations in the X-linked recessive PRPP SYNTHASE/RPDPKINASE?

<p>Gout and sensorineural hearing loss</p> Signup and view all the answers

Which enzyme catalyzes the committed step in purine biosynthesis, forming the N-glycosidic bond of the purine nucleotide?

<p>Glutamine phosphoribosyl amidotransferase</p> Signup and view all the answers

What is the carrier of activated one-carbon units obtained from diets or microorganisms in intestinal tracts?

<p>Tetrahydrofolate</p> Signup and view all the answers

Which compound selectively inhibits bacterial dihydrofolate reductase and has potent antibacterial activity?

<p>Trimethoprim</p> Signup and view all the answers

What is the structural analog of folic acid used to control cancer spread by interfering with nucleotides for DNA and RNA?

<p>Methotrexate</p> Signup and view all the answers

What can rescue normal cells from the toxic effects of methotrexate by acting as a synthetic inhibitor of purine synthesis?

<p>N5formylH folate (leucovorin)</p> Signup and view all the answers

What is the name of the purine antagonists with antineoplastic and antibiotic properties, inhibiting amidotransferases?

<p>Azaserine and 6-diazo-5-oxo-norleucine</p> Signup and view all the answers

What is the phosphoryl-grp donor for the synthesis of adenylsuccinate?

<p>GTP</p> Signup and view all the answers

What is the hydrogen acceptor in the oxidation of inosinate to xanthylate?

<p>NAD+</p> Signup and view all the answers

What is the reciprocal use of nucleotides by the pathways an important regulatory opportunity for?

<p>Regulating purine biosynthesis</p> Signup and view all the answers

What is the potent, reversible, uncompetitive inhibitor of inosine monophosphate dehydrogenase?

<p>Mycophenolic acid</p> Signup and view all the answers

Which nucleotide is required for the synthesis of adenylate?

<p>GTP</p> Signup and view all the answers

Which nucleotide is required for the synthesis of guanylate?

<p>ATP</p> Signup and view all the answers

What is the carrier of activated one-carbon units obtained from diets or microorganisms in intestinal tracts?

<p>Tetrahydrofolate</p> Signup and view all the answers

What is the final intermediate formed by the addition of a formyl group from N10-formyltetrahydrofolate to a nitrogen atom?

<p>N10-formyl-THF</p> Signup and view all the answers

What is the molecule required for the substitution of NH3 for the c=0 oxygen atom at C-6 in the synthesis of adenylate from inosinate?

<p>Aspartate</p> Signup and view all the answers

What is the activated intermediate that participates in biosynthetic processes such as glycogen synthesis?

<p>Adenylsuccinate</p> Signup and view all the answers

Which enzyme is involved in the first step synthesis of carbamoyl phosphate from bicarbonate and ammonia?

<p>Carbamoyl phosphate synthetase II</p> Signup and view all the answers

Which enzyme is responsible for transferring the formyl group from N10-formyltetrahydrofolate to glycine in the purine biosynthesis pathway?

<p>Glycinamide ribonucleotide transformylase</p> Signup and view all the answers

Which enzyme catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate (PRPP) to 5-phosphoribosylamine, the committed step in purine biosynthesis?

<p>PRPP amidotransferase</p> Signup and view all the answers

Which enzyme catalyzes the removal of fumarate from 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide in the synthesis of inosinate?

<p>Aminoimidazole carboxamide ribonucleotide transformylase</p> Signup and view all the answers

What is the precursor for the formation of the cofactor tetrahydrobiopterin?

<p>Ammonia</p> Signup and view all the answers

Which enzyme catalyzes the conversion of dihydrofolate to tetrahydrofolate in mammals?

<p>Dihydrofolate reductase</p> Signup and view all the answers

Which enzyme is responsible for the activation of the glycine carboxyl group by consuming ATP in the purine biosynthesis pathway?

<p>PRPP amidotransferase</p> Signup and view all the answers

What is the activated precursor of nucleic acids necessary for the replication of the genome?

<p>PRPP</p> Signup and view all the answers

What is the molecule required for the substitution of NH3 for the C=O oxygen atom at C-6 in the synthesis of adenylate from inosinate?

<p>Ammonia</p> Signup and view all the answers

What do coenzymes NAD+, NADP+, FAD, and coenzyme A contain as part of their structures?

<p>Nicotinamide</p> Signup and view all the answers

Which enzyme is involved in the synthesis of tetrahydrofolate, a carrier of activated one-carbon units?

<p>Dihydrofolate reductase</p> Signup and view all the answers

Which drug is a structural analog of folic acid and is used to control the spread of cancer by interfering with nucleotides for DNA and RNA?

<p>Mycophenolic acid</p> Signup and view all the answers

What is the final carbon contributed by in the synthesis of the second fused ring of the purine nucleus?

<p>Glycine</p> Signup and view all the answers

Which compound is consumed to ensure irreversibility in the intramolecular reaction in which the nucleophile and phosphate-activated carbon atom AIR synthetase (FGAM cyclase)?

<p>ATP</p> Signup and view all the answers

Which enzyme catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate (PRPP) to 5-phosphoribosylamine, the committed step in purine biosynthesis?

<p>Glutamine-PRPP amidotransferase</p> Signup and view all the answers

Which enzyme is particularly active in high energy turnover tissues like liver and muscle?

<p>Adenylate kinase</p> Signup and view all the answers

What is the activated precursor of nucleic acids necessary for the replication of the genome?

<p>IMP</p> Signup and view all the answers

Which enzyme is responsible for transferring the formyl group from N10-formyltetrahydrofolate to glycine in the purine biosynthesis pathway?

<p>Serine hydroxymethyltransferase</p> Signup and view all the answers

Which molecule is required for the substitution of NH3 for the C=O oxygen atom at C-6 in the synthesis of adenylate from inosinate?

<p>Glutamine</p> Signup and view all the answers

Which enzyme catalyzes the removal of fumarate from 5-aminoimidazole-4-N-succinocarboxamide ribonucleotide in the synthesis of inosinate?

<p>IMP dehydrogenase</p> Signup and view all the answers

Study Notes

Nucleotide Biosynthesis and Purine Biosynthesis

  • Purine base is synthesized directly onto a ribose-based structure in ten metabolic steps, with inosine 5’-monophosphate (IMP) as the common precursor for AMP and GMP
  • The synthesis of purine nucleotides is expensive, utilizing the equivalent of 6 moles of ATP per mole of IMP synthesized
  • All enzymes involved in the synthesis of purine nucleotides are found in the cytosol of the cell
  • Mutations in the X-linked recessive PRPP SYNTHASE/RPDPKINASE lead to purine and uric acid overproduction, causing conditions like gout and sensorineural hearing loss
  • The enzyme Glutamine phosphoribosyl amidotransferase catalyzes the committed step in purine biosynthesis, forming the N-glycosidic bond of the purine nucleotide
  • Purine biosynthesis enzyme comprises two domains, with the second producing NH3 from glutamine by hydrolysis
  • Azaserine and 6-diazo-5-oxo-norleucine are purine antagonists with antineoplastic and antibiotic properties, inhibiting amidotransferases
  • The next six steps in purine biosynthesis involve the activation of a carbon-bound oxygen atom by phosphorylation, followed by the displacement of a phosphoryl group by NH3 or an R-NH3 group
  • Tetrahydrofolate, a carrier of activated one-carbon units, is obtained from diets or microorganisms in intestinal tracts, and its deficiency is linked to megaloblastic anemia
  • Trimethoprim, a folate analog, selectively inhibits bacterial dihydrofolate reductase and has potent antibacterial activity
  • Methotrexate, a structural analog of folic acid, is used to control cancer spread by interfering with nucleotides for DNA and RNA, with toxic effects on rapidly replicating cells
  • Normal cells can be rescued from the toxic effects of methotrexate by N5formylH folate (leucovorin), which acts as a synthetic inhibitor of purine synthesis

Purine Nucleotide Metabolism and Immunodeficiency Diseases

  • De novo formation of GMP is blocked, affecting T and B cells by depriving them of a key component of nucleic acids
  • NMPs are converted to NDP and NTP by base-specific kinases, using ATP as the phosphate source
  • Adenylate kinase is particularly active in high energy turnover tissues like liver and muscle
  • Glutathione and Thioredoxin serve as reductants for ribonucleotide reductase
  • DeoxyATP, dGTP, and dTTP inhibit reduction of specific substrates, impacting DNA synthesis
  • Hydroxyurea and tiazofurin are inhibitors of ribonucleotide reductase, affecting DNA synthesis
  • Adenosine deaminase deficiency leads to a buildup of dATP, inhibiting ribonucleotide reductase and DNA synthesis
  • Purine nucleoside phosphorylase (PNP-deficiency) leads to T-cell toxicity due to elevated dGTP levels
  • Pentostatin is a potent inhibitor of ADA, mimicking genetic ADA deficiency and affecting T- and B-cell functions
  • Cladribine, a purine analog, causes DNA strand breaks and apoptosis, depleting NAD and ATP
  • Allopurinol is used to treat gout by inhibiting xanthine oxidase and decreasing uric acid levels
  • Salvage pathways for purine bases and nucleosides economize intracellular energy expenditure and are regulated by end products of the reactions

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