BIOL 4003 EXAM 2 Questions With Complete Solutions
A chromosome territory region is a region
a. of a chromosome that carries a cluster of genes
b. of a chromosome that has particular sets of DNA-binding
proteins
c. in a cell nucleus that is occupied by a single chromosome
d. in a dividing cell where a chromosome will travel via the
spindle apparatus Correct Answers c
A gene encodes a pre-mRNA with 8 axons and 7 introns. A
mutation eliminates the 3' splice site from intron 5. What exons
would be found in the mRNA after splicing was complete?
a. 1-2-3-4-5-6-7-8
b. 1-2-3-4-6-7-8
c. 1-2-3-4-5-7-8
d. 1-2-3-4-7-8 Correct Answers c
A gene exists in two alleles, which we will call B and b. The
gene is 1123 bp in length, and the B and b alleles exhibit single
base pair differences at six different sites. If gene conversion
changed the b allele into the B allele, which mechanism would
you favor to explain this conversion?
a. mismatch repair
b. gap repair synthesis
c. nucleotide excision repair
d. direct repair Correct Answers b
A gene that encodes a tRNA changes the anticodon from GAG
to CAG. This mutation does not alter which amino acid is
,attached to the mutant tRNA. What effect would this mutation
have on translation?
a. it would have no effect due to the wobble rules
b. it could introduce a leucine where a stop codon occurs
c. it could introduce a leucine where a valine is supposed to be
d. it could introduce a valine where a leucine is supposed to be
Correct Answers c
A key event that promotes trinucleotide repeat expansion is
a. chromosome breakage
b. the formation of a hairpin
c. the presence of an AT-rich region
d. the presence of a lesion in the DNA Correct Answers b
A mutation changes a valine codon to a histidine codon. This is
a
a. silent mutation
b. missense mutation
c. frameshift mutation
d. nonsense mutation Correct Answers b
A mutation in the lacZ gene alters B-galactosidase so it makes
more allolactose compared with a normal B-galactosidase
enzyme. How would this mutation affect the expression of the
lac operon?
a. the lac operon could not be expressed in the presence of
lactose in the environment
b. the lac operon would be constitutively expressed in the
absence of lactose
c. it would require less lactose in the environment to express the
lac operon
, d. it would require more lactose in the environment to express
the lac operon Correct Answers c
A mutation prevents the lac repressor from recognizing
allolactose. In the absence of allolatose, the mutant repressor has
the same affinity for the lac operator sites as a normal repressor.
How would you expect this mutant repressor to affect regulation
of the lac operon? Assume no glucose is present.
a. the operon would be turned on in the presence or absence of
lactose in the environment
b. the operon would be turned off in the presence or absence of
lactose in the environment
c. the operon would be turned off in the presence of lactose but
turned on in lactose
d. the operon would be turned on in the presence of lactose but
turned off in its absence Correct Answers b
A mutation that encodes the lac repressor prevents allolactose
from binding to the repressor. Even so, the lac repressor can still
bind to the operator site. How would you expect this mutation to
affect the regulation of the lac operon?
a. the operon would be turned on in the presence or absence of
lactose
b. the operon would be turned off in the presence or absence of
lactose
c. the operon would be turned off in the presence of lactose but
would be turned on in its absence
d. the operon would be turned on in the presence of lactose but
would be turned off in its absence Correct Answers b
A chromosome territory region is a region
a. of a chromosome that carries a cluster of genes
b. of a chromosome that has particular sets of DNA-binding
proteins
c. in a cell nucleus that is occupied by a single chromosome
d. in a dividing cell where a chromosome will travel via the
spindle apparatus Correct Answers c
A gene encodes a pre-mRNA with 8 axons and 7 introns. A
mutation eliminates the 3' splice site from intron 5. What exons
would be found in the mRNA after splicing was complete?
a. 1-2-3-4-5-6-7-8
b. 1-2-3-4-6-7-8
c. 1-2-3-4-5-7-8
d. 1-2-3-4-7-8 Correct Answers c
A gene exists in two alleles, which we will call B and b. The
gene is 1123 bp in length, and the B and b alleles exhibit single
base pair differences at six different sites. If gene conversion
changed the b allele into the B allele, which mechanism would
you favor to explain this conversion?
a. mismatch repair
b. gap repair synthesis
c. nucleotide excision repair
d. direct repair Correct Answers b
A gene that encodes a tRNA changes the anticodon from GAG
to CAG. This mutation does not alter which amino acid is
,attached to the mutant tRNA. What effect would this mutation
have on translation?
a. it would have no effect due to the wobble rules
b. it could introduce a leucine where a stop codon occurs
c. it could introduce a leucine where a valine is supposed to be
d. it could introduce a valine where a leucine is supposed to be
Correct Answers c
A key event that promotes trinucleotide repeat expansion is
a. chromosome breakage
b. the formation of a hairpin
c. the presence of an AT-rich region
d. the presence of a lesion in the DNA Correct Answers b
A mutation changes a valine codon to a histidine codon. This is
a
a. silent mutation
b. missense mutation
c. frameshift mutation
d. nonsense mutation Correct Answers b
A mutation in the lacZ gene alters B-galactosidase so it makes
more allolactose compared with a normal B-galactosidase
enzyme. How would this mutation affect the expression of the
lac operon?
a. the lac operon could not be expressed in the presence of
lactose in the environment
b. the lac operon would be constitutively expressed in the
absence of lactose
c. it would require less lactose in the environment to express the
lac operon
, d. it would require more lactose in the environment to express
the lac operon Correct Answers c
A mutation prevents the lac repressor from recognizing
allolactose. In the absence of allolatose, the mutant repressor has
the same affinity for the lac operator sites as a normal repressor.
How would you expect this mutant repressor to affect regulation
of the lac operon? Assume no glucose is present.
a. the operon would be turned on in the presence or absence of
lactose in the environment
b. the operon would be turned off in the presence or absence of
lactose in the environment
c. the operon would be turned off in the presence of lactose but
turned on in lactose
d. the operon would be turned on in the presence of lactose but
turned off in its absence Correct Answers b
A mutation that encodes the lac repressor prevents allolactose
from binding to the repressor. Even so, the lac repressor can still
bind to the operator site. How would you expect this mutation to
affect the regulation of the lac operon?
a. the operon would be turned on in the presence or absence of
lactose
b. the operon would be turned off in the presence or absence of
lactose
c. the operon would be turned off in the presence of lactose but
would be turned on in its absence
d. the operon would be turned on in the presence of lactose but
would be turned off in its absence Correct Answers b
