BIOC 385 EXAM 4 questions and
correct answers
An Ames test of a compound suspected to be a mutagen was examined before and after
incubation with rat liver extract. Based on the results shown, what do you conclude? - correct
answer ✔✔Compound is mutagenic without liver enzymes and this activity is further enhanced
by liver enzymes.
Match the description of each mode of regulation with the illustration diagrammed at the right
and record your answer in the order of 1->4
1. _ Ligand-regulated de-repression
2. _ Ligand-regulated repression
3. _ Ligand-regulated activation
4. _ Ligand-regulated de-activation - correct answer ✔✔B, A, D, C
Lynch syndrome is a human genetic disease characterized by ~100-fold higher incidence ofcolon
cancer in men and women - and uterine cancer in women - by the age 50, as compared to
thegeneral population. Which statement below best describes the genetic cause of Lynch
syndrome. - correct answer ✔✔Lynch syndrome is caused by defects in the human mismatch
repair enzymes hMLH1 and hMSH2.
Record T (true) or F (false) for statements below regarding protein synthesis. Record as a->e
T F a. Prokaryotic and eukaryotic ribosomes both contain RNA that functions as a catalytic
enzyme.
T F b. The wobble position in tRNA is 5' nucleotide in the anti-codon and 3' nucleotide in mRNA
codon.
T F c. Ribosomal E, P, and A sites align tRNA anti-codons with the corresponding mRNA codons.
, T F d. Accurate protein synthesis requires tRNA synthetases to link GTP to 3' end of tRNA
molecules.
T F e. Cells contain only ~30 tRNA molecules, of which 3 correspond to termination tRNA
molecules. - correct answer ✔✔T, T, T, F, F
Why are the BRCA1/BRCA2 genes considered tumor suppressor genes? - correct answer
✔✔Because BRCA1/BRCA2 encode DNA repair enzymes that normally prevent cancer
mutations.
Five different TATA Binding Protein (TBP) mutations are shown below. If these mutations were
located in the region of the protein that is required for direct binding to the TATAA DNA
sequence, which mutation would most likely be a conservative missense mutation that does not
alter TBP function? - correct answer ✔✔Lys -> Arg
Which of the following statements about pluripotent stem cells is true? - correct answer
✔✔They can develop into many different cell types under the right conditions.
Choose the best answer that correctly identifies the labeled DNA and RNA sequences. Your
choices for A, B, C, D, E are shown in the box.
5'.....GGCAUGUGCCAAUGCC.....3' (X)
3'.....CCGTACACGGTTACGG......5' (Y)
5'.....GGCATGTGCCAATGCC......3' (Z) - correct answer ✔✔X is RNA
Z is DNA coding
Y is DNA template.
Which five statements below are correctregarding the process of prokaryotic DNA replication?
1. b-clamp keeps DNA Pol bound to DNA
correct answers
An Ames test of a compound suspected to be a mutagen was examined before and after
incubation with rat liver extract. Based on the results shown, what do you conclude? - correct
answer ✔✔Compound is mutagenic without liver enzymes and this activity is further enhanced
by liver enzymes.
Match the description of each mode of regulation with the illustration diagrammed at the right
and record your answer in the order of 1->4
1. _ Ligand-regulated de-repression
2. _ Ligand-regulated repression
3. _ Ligand-regulated activation
4. _ Ligand-regulated de-activation - correct answer ✔✔B, A, D, C
Lynch syndrome is a human genetic disease characterized by ~100-fold higher incidence ofcolon
cancer in men and women - and uterine cancer in women - by the age 50, as compared to
thegeneral population. Which statement below best describes the genetic cause of Lynch
syndrome. - correct answer ✔✔Lynch syndrome is caused by defects in the human mismatch
repair enzymes hMLH1 and hMSH2.
Record T (true) or F (false) for statements below regarding protein synthesis. Record as a->e
T F a. Prokaryotic and eukaryotic ribosomes both contain RNA that functions as a catalytic
enzyme.
T F b. The wobble position in tRNA is 5' nucleotide in the anti-codon and 3' nucleotide in mRNA
codon.
T F c. Ribosomal E, P, and A sites align tRNA anti-codons with the corresponding mRNA codons.
, T F d. Accurate protein synthesis requires tRNA synthetases to link GTP to 3' end of tRNA
molecules.
T F e. Cells contain only ~30 tRNA molecules, of which 3 correspond to termination tRNA
molecules. - correct answer ✔✔T, T, T, F, F
Why are the BRCA1/BRCA2 genes considered tumor suppressor genes? - correct answer
✔✔Because BRCA1/BRCA2 encode DNA repair enzymes that normally prevent cancer
mutations.
Five different TATA Binding Protein (TBP) mutations are shown below. If these mutations were
located in the region of the protein that is required for direct binding to the TATAA DNA
sequence, which mutation would most likely be a conservative missense mutation that does not
alter TBP function? - correct answer ✔✔Lys -> Arg
Which of the following statements about pluripotent stem cells is true? - correct answer
✔✔They can develop into many different cell types under the right conditions.
Choose the best answer that correctly identifies the labeled DNA and RNA sequences. Your
choices for A, B, C, D, E are shown in the box.
5'.....GGCAUGUGCCAAUGCC.....3' (X)
3'.....CCGTACACGGTTACGG......5' (Y)
5'.....GGCATGTGCCAATGCC......3' (Z) - correct answer ✔✔X is RNA
Z is DNA coding
Y is DNA template.
Which five statements below are correctregarding the process of prokaryotic DNA replication?
1. b-clamp keeps DNA Pol bound to DNA
