ETS MAJOR FIELD EXAMINATION TEST 2026
QUESTIONS WITH ANSWERS GRADED A+
◉ Which of the following repair mechanisms uses methyl groups to
distinguish between parental and daughter strands?
Answers:
Mismatch repair
Photoreactivation repair (Nucleotide excision repair)
SOS repair
Double strand break repair
Base excision repair. Answer: Mismatch repair
◉ Which of the following types of molecules is always found in virions?
Answers:
Protein
RNA
Lipid
DNA
Carbohydrate. Answer: Protein
,◉ A Barr body found within the female mammalian cell's nucleus is an
example of ___
Answers:
Euchromatin
Polytene chromosome
Pseudogenes
Heterochromatin
Cistron. Answer: Heterochromatin
◉ In vertebrate genes, transcription regulatory regions that contain CpG
islands are inactivated by which CpG modification?
Answers:
Methylation
Ubiquitination
Acetylation
Phosphorylation
Myristoylation. Answer: Methylation
◉ TATA-binding protein (TBP) is a key transcription factor in
eukaryotes. A schematic representation of the 240-amino acid TBP of
yeast is shown in Fig. 1 below, with the positions of 2 mutations
indicated. The boxed area represents the evolutionarily conserved C-
terminal domain of TBP, and the shaded (dark) regions of this domain
represent two repeated elements involved in DNA binding. One
,mutation (P65S) changes proline 65 to serine and the other I143N
changes isoleucine 143 to asparagine. Fig. 2 below represents
autoradiographs of gels containing RNA transcripts produced in extracts
of wild type or mutant cells. Lanes 1-2 are from wild-type yeast (WT),
lanes 3-4 are from the I143N mutant and lanes 5-6 are from P65S
mutant, as indicated. Fig. 2A shows transcripts of a gene transcribed by
RNA polymerase I (Pol I). Fig. 2B shows transcripts of a gene
transcribed by RNA polymerase II (Pol II). Fig. 2C shows transcripts.
Answer: Whether mutant transcription phenotypes are due to
perturbation of TBP function.
◉ A set of genes from Bacillus subtilis that encode the proteins required
for sporulation have conserved DNA sequences -35 and -10 nucleotides
before the site of transcript initiation. However, the sequence at -35 is
different from that seen in most other genes from that species. Which of
the following best explains this difference?
Answers:
Transcription of these genes is induced by cAMP
Translation of the mRNAs transcribed from these genes requires specific
ribosomes that recognize a modified Shine-Dalgarno sequence
A novel sigma factor is required for transcription initiation at these genes
The -35 sequence is the binding site for a repressor of transcription
The replication of these genes requires a specifically modified DNA
polymerase.. Answer: A novel sigma factor is required for transcription
initiation at these genes
, ◉ Which of the following repair mechanisms is often mutagenic?
Answers:
Mismatch repair
Photoreactivation repair (Nucleotide excision repair)
Base excision repair
SOS repair. Answer: SOS repair
◉ The polytene chromosomes seen in Drosophila are
Answers:
Multiple copies of a single chromosome
Produced by repeated rounds of DNA replication followed by nuclear
division
Produced only after the completion of mitosis
Not carrying out transcription
smooth in appearance. Answer: Multiple copies of a single chromosome
◉ A frameshift mutation is created when
Answers:
A codon's nucleotide sequence changes so that it calls for production of
a different amino acid than the original one
An initial mutation is reversed by a second mutation
A codon's nucleotide sequence changes so that instead of coding for a
given amino acid, it acts to terminate translation
QUESTIONS WITH ANSWERS GRADED A+
◉ Which of the following repair mechanisms uses methyl groups to
distinguish between parental and daughter strands?
Answers:
Mismatch repair
Photoreactivation repair (Nucleotide excision repair)
SOS repair
Double strand break repair
Base excision repair. Answer: Mismatch repair
◉ Which of the following types of molecules is always found in virions?
Answers:
Protein
RNA
Lipid
DNA
Carbohydrate. Answer: Protein
,◉ A Barr body found within the female mammalian cell's nucleus is an
example of ___
Answers:
Euchromatin
Polytene chromosome
Pseudogenes
Heterochromatin
Cistron. Answer: Heterochromatin
◉ In vertebrate genes, transcription regulatory regions that contain CpG
islands are inactivated by which CpG modification?
Answers:
Methylation
Ubiquitination
Acetylation
Phosphorylation
Myristoylation. Answer: Methylation
◉ TATA-binding protein (TBP) is a key transcription factor in
eukaryotes. A schematic representation of the 240-amino acid TBP of
yeast is shown in Fig. 1 below, with the positions of 2 mutations
indicated. The boxed area represents the evolutionarily conserved C-
terminal domain of TBP, and the shaded (dark) regions of this domain
represent two repeated elements involved in DNA binding. One
,mutation (P65S) changes proline 65 to serine and the other I143N
changes isoleucine 143 to asparagine. Fig. 2 below represents
autoradiographs of gels containing RNA transcripts produced in extracts
of wild type or mutant cells. Lanes 1-2 are from wild-type yeast (WT),
lanes 3-4 are from the I143N mutant and lanes 5-6 are from P65S
mutant, as indicated. Fig. 2A shows transcripts of a gene transcribed by
RNA polymerase I (Pol I). Fig. 2B shows transcripts of a gene
transcribed by RNA polymerase II (Pol II). Fig. 2C shows transcripts.
Answer: Whether mutant transcription phenotypes are due to
perturbation of TBP function.
◉ A set of genes from Bacillus subtilis that encode the proteins required
for sporulation have conserved DNA sequences -35 and -10 nucleotides
before the site of transcript initiation. However, the sequence at -35 is
different from that seen in most other genes from that species. Which of
the following best explains this difference?
Answers:
Transcription of these genes is induced by cAMP
Translation of the mRNAs transcribed from these genes requires specific
ribosomes that recognize a modified Shine-Dalgarno sequence
A novel sigma factor is required for transcription initiation at these genes
The -35 sequence is the binding site for a repressor of transcription
The replication of these genes requires a specifically modified DNA
polymerase.. Answer: A novel sigma factor is required for transcription
initiation at these genes
, ◉ Which of the following repair mechanisms is often mutagenic?
Answers:
Mismatch repair
Photoreactivation repair (Nucleotide excision repair)
Base excision repair
SOS repair. Answer: SOS repair
◉ The polytene chromosomes seen in Drosophila are
Answers:
Multiple copies of a single chromosome
Produced by repeated rounds of DNA replication followed by nuclear
division
Produced only after the completion of mitosis
Not carrying out transcription
smooth in appearance. Answer: Multiple copies of a single chromosome
◉ A frameshift mutation is created when
Answers:
A codon's nucleotide sequence changes so that it calls for production of
a different amino acid than the original one
An initial mutation is reversed by a second mutation
A codon's nucleotide sequence changes so that instead of coding for a
given amino acid, it acts to terminate translation
