BIOC 385 Exam 3 questions well
answered
Which of the following amino acids is part of the Group 2 amino acid degradation pathway?
A. Glycine
B. Proline
C. Phenylalanine
D. Cysteine - correct answer ✔✔B. Proline
Which of the following is a starting material for the synthesis of heme?
A. Phenylalanine
B. Glycine
C. Histidine
D. Alanine - correct answer ✔✔B. Glycine
Which of the following chemical moieties compose tetrahydrofolate (THF)?
A. indole
B. serine
C. a pterin
D. glutamate - correct answer ✔✔C. a pterin
D. glutamate
THF derivatives are interconverted to generate transferable C1 groups that differ by the level of
oxidation. In addition to methylene (-CH2-), formyl (-CHO), and formimino (-CH=NH) groups, the
other transferable groups are which two of the following?
,A. a carbonyl group (-C=O)
B. a phosphate group (-PO4)
C. a methenyl group (-CH=)
D. a methyl group (-CH3)
E. an aldehyde (-C=OH)
F. a carboxylic acid (-C=OOH) - correct answer ✔✔C. a methenyl group (-CH=)
D. a methyl group (-CH3)
Which two of the following reactions utilize tetrahydrofolate?
A. conversion of homocysteine to methionine
B. conversion of pyruvate to alanine
C. conversion of glycine to serine
D. conversion of proline to glutamate - correct answer ✔✔A. conversion of homocysteine to
methionine
C. conversion of glycine to serine
Which amino acid in a target protein for proteasomal degradation is tagged by ubiquitin?
A. Lysine
B. Tyrosine
C. Arginine
D. Serine - correct answer ✔✔A. Lysine
Which of the following is correct and most accurately describes the complete urea cycle of the
eukaryotic cell?
A. The urea cycle occurs between the inner mitochondrial membrane and the matrix of the
eukaryotic cell.
B. The urea cycle occurs completely within the cytoplasm of the eukaryotic cell.
,C. The urea cycle occurs between the mitochondrial matrix and the cytoplasm of the eukaryotic
cell.
D. The urea cycle occurs completely within the mitochondrial matrix of the eukaryotic cell. -
correct answer ✔✔C. The urea cycle occurs between the mitochondrial matrix and the
cytoplasm of the eukaryotic cell.
Which two cellular changes would not encourage the Krebs bicycle and thus the probability of
the urea cycle taking place to completion?
A. increased citrulline being transported into the cytoplasm
B. increased conversion of oxaloacetate into citrate
C. increased import of ornithine into the mitochondria
D. increased aspartate charging to mitochondrial tRNAs - correct answer ✔✔B. increased
conversion of oxaloacetate into citrate
D. increased aspartate charging to mitochondrial tRNAs
Which of the following is the product of uracil degradation?
A. Cytidine
B. β-alanine
C. β-aminoisobutyrate
D. Thymine - correct answer ✔✔B. β-alanine
There are ----- α helices that comprise the secondary structures of thymidylate synthase, and
some of these α helices comprise the active site of thymidylate synthase. - correct answer ✔✔8
Considering the physiology of thymidylate synthase, why is Tomudex an effective anticancer
drug?
, A. The drug is a competitive inhibitor that binds to thymidylate synthase and decreases
enzymatic activity. This causes an imbalance in the quantities of dNTPs that are available for
DNA replication.
B. The drug is a nucleotide analog that binds to thymidylate synthase and decreases enzymatic
activity because the drug is converted by the enzyme into an unusable dNTP.
C. The drug is an enzyme activator that binds to thymidylate synthase and increases enzymatic
activity. This causes an excess of dNTPs that are available for DNA replication.
D. The drug is a noncompetitive inhibitor that binds to thymidylate synthase and decreases
enzymatic activity. This causes an imbalance in the quantities of dNTPs that are available for
DNA replication. - correct answer ✔✔D. The drug is a noncompetitive inhibitor that binds to
thymidylate synthase and decreases enzymatic activity. This causes an imbalance in the
quantities of dNTPs that are available for DNA replication.
Which enzyme deficiency is responsible for Lesch-Nyhan syndrome?
A. Adenosine deaminase
B. PRPP synthetase
C. Xanthine oxidase
D. HGPRT - correct answer ✔✔D. HGPRT
Which of the following contributes both carbon and nitrogen to the purine ring system?
A. Glycine
B. N10-formyl-tetrahydrofolate
C. Aspartate
D. Glutamine - correct answer ✔✔A. Glycine
The amidation reaction during CTP synthesis uses glutamine as the source of nitrogen in most
species; however, bacteria use ----- - correct answer ✔✔NH4+
Which of the following best describes the nucleotide in this image?
answered
Which of the following amino acids is part of the Group 2 amino acid degradation pathway?
A. Glycine
B. Proline
C. Phenylalanine
D. Cysteine - correct answer ✔✔B. Proline
Which of the following is a starting material for the synthesis of heme?
A. Phenylalanine
B. Glycine
C. Histidine
D. Alanine - correct answer ✔✔B. Glycine
Which of the following chemical moieties compose tetrahydrofolate (THF)?
A. indole
B. serine
C. a pterin
D. glutamate - correct answer ✔✔C. a pterin
D. glutamate
THF derivatives are interconverted to generate transferable C1 groups that differ by the level of
oxidation. In addition to methylene (-CH2-), formyl (-CHO), and formimino (-CH=NH) groups, the
other transferable groups are which two of the following?
,A. a carbonyl group (-C=O)
B. a phosphate group (-PO4)
C. a methenyl group (-CH=)
D. a methyl group (-CH3)
E. an aldehyde (-C=OH)
F. a carboxylic acid (-C=OOH) - correct answer ✔✔C. a methenyl group (-CH=)
D. a methyl group (-CH3)
Which two of the following reactions utilize tetrahydrofolate?
A. conversion of homocysteine to methionine
B. conversion of pyruvate to alanine
C. conversion of glycine to serine
D. conversion of proline to glutamate - correct answer ✔✔A. conversion of homocysteine to
methionine
C. conversion of glycine to serine
Which amino acid in a target protein for proteasomal degradation is tagged by ubiquitin?
A. Lysine
B. Tyrosine
C. Arginine
D. Serine - correct answer ✔✔A. Lysine
Which of the following is correct and most accurately describes the complete urea cycle of the
eukaryotic cell?
A. The urea cycle occurs between the inner mitochondrial membrane and the matrix of the
eukaryotic cell.
B. The urea cycle occurs completely within the cytoplasm of the eukaryotic cell.
,C. The urea cycle occurs between the mitochondrial matrix and the cytoplasm of the eukaryotic
cell.
D. The urea cycle occurs completely within the mitochondrial matrix of the eukaryotic cell. -
correct answer ✔✔C. The urea cycle occurs between the mitochondrial matrix and the
cytoplasm of the eukaryotic cell.
Which two cellular changes would not encourage the Krebs bicycle and thus the probability of
the urea cycle taking place to completion?
A. increased citrulline being transported into the cytoplasm
B. increased conversion of oxaloacetate into citrate
C. increased import of ornithine into the mitochondria
D. increased aspartate charging to mitochondrial tRNAs - correct answer ✔✔B. increased
conversion of oxaloacetate into citrate
D. increased aspartate charging to mitochondrial tRNAs
Which of the following is the product of uracil degradation?
A. Cytidine
B. β-alanine
C. β-aminoisobutyrate
D. Thymine - correct answer ✔✔B. β-alanine
There are ----- α helices that comprise the secondary structures of thymidylate synthase, and
some of these α helices comprise the active site of thymidylate synthase. - correct answer ✔✔8
Considering the physiology of thymidylate synthase, why is Tomudex an effective anticancer
drug?
, A. The drug is a competitive inhibitor that binds to thymidylate synthase and decreases
enzymatic activity. This causes an imbalance in the quantities of dNTPs that are available for
DNA replication.
B. The drug is a nucleotide analog that binds to thymidylate synthase and decreases enzymatic
activity because the drug is converted by the enzyme into an unusable dNTP.
C. The drug is an enzyme activator that binds to thymidylate synthase and increases enzymatic
activity. This causes an excess of dNTPs that are available for DNA replication.
D. The drug is a noncompetitive inhibitor that binds to thymidylate synthase and decreases
enzymatic activity. This causes an imbalance in the quantities of dNTPs that are available for
DNA replication. - correct answer ✔✔D. The drug is a noncompetitive inhibitor that binds to
thymidylate synthase and decreases enzymatic activity. This causes an imbalance in the
quantities of dNTPs that are available for DNA replication.
Which enzyme deficiency is responsible for Lesch-Nyhan syndrome?
A. Adenosine deaminase
B. PRPP synthetase
C. Xanthine oxidase
D. HGPRT - correct answer ✔✔D. HGPRT
Which of the following contributes both carbon and nitrogen to the purine ring system?
A. Glycine
B. N10-formyl-tetrahydrofolate
C. Aspartate
D. Glutamine - correct answer ✔✔A. Glycine
The amidation reaction during CTP synthesis uses glutamine as the source of nitrogen in most
species; however, bacteria use ----- - correct answer ✔✔NH4+
Which of the following best describes the nucleotide in this image?
