BCH 5413 EXAM 2 | 92 COMPLETE
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) | GRADED A+ |
LATEST UPDATE 2025-2026
What is the meaning of the term transgenic? - ANSWER A transgenic organism
is one whose genome has been altered by the random introduction of a foreign
piece of DNA. Researchers often compare transgenic organisms to wild type or
control organisms to determine the effect the transgene has. The amount of DNA
inserted can vary from 1-200 base pairs
When determining if an additional copy of a gene added to a mouse genome
using PCR, how would you be able to distinguish between the endogenous gene
and the transgene? - ANSWER For PCR, I use two primers, one inside the
transgene and one outside the transgene, so I can distinguish the endogenous
gene from the transgene. Since only the transgene can bind with these two
primers and be amplified.
When determining if an additional copy of a gene added to a mouse genome
using a Southern blot, how would you be able to distinguish between the
endogenous gene and the transgene? - ANSWER Like PCR, I will use one probe
to target the gene and another probe to target the vector in Southern Blot. When
there is only one band with the size of the gene, then it is an endogenous gene. If
there are two bands, one is with the size of the gene, another is the size of the
vector, and it is the transgene.
What would be the purpose of creating a reporter gene as a transgene? What
types of experimental questions might you be able to ask and answer? -
ANSWER Reporter genes are used to investigate the expression of other genes
,whose expression we need to measure in a transgenic animal. Reporter genes
"report" whether the gene of interest is expressed or not, or the location of gene
expression.
In the lecture, the example of the HKβ subunit gene is given, in which using a
reporter gene, scientists want to investigate the location of expression of the HKβ
subunit gene in the tissues of a transgenic mouse. LacZ gene is used as a reporter
and the HKβ control region is placed in front of the LacZ gene in a plasmid vector.
Now the tissues that expressed the HKβ subunit gene also expressed the reporter
LacZ gene and it became easier for the scientists to locate the expression of the
HKβ subunit gene because of the blue color of the tissues, expressed by the LacZ
gene whose product is β-galactosidase.
Other reporter genes mentioned in the textbook include the luciferase gene from
firefly and the bacterial gene cat that encodes chloramphenicol acetyl transferase
enzyme (CAT).
When creating a knockout animal, why do you need to engineer ES cells? -
ANSWER **Able to perform manipulation of the genome but the cells still
grow into a whole organism. ES cells give rise to all body tissue types. iPS cells:
take cells that are differentiated and cause them too undifferentiated.
**ES cells = pluripotent, used to knock out genes of interest.
When creating knockout ES cells, why do you need to isolate cells that are
sensitive to G418 AND ganciclovir? - ANSWER To tell you where your
transgene is being expressed!
, G418 neomycin analog kills cell without neomycin-resistance gene (cells with no
integration)
Gangcyclovir kills cells containing thymidine kinase gene (cells with non-specific
recombination)
Cells that grow on medium will have homologous recombination between the
plasmid and WT gene
When creating a knockout mouse, the chimeric animal is mated with one that is
black and normal for the gene of interest. From this cross, three possible offspring
can be produced. Explain the genetics of each of the three and what you would do
next with the desired offspring. - ANSWER possible progeny genomes include:
A/X+ (brown, no gene of interest), A/X- (brown, gene of interest), a/X+ (black, no
gene of interest) in which A/X- is the most desirable genome.
I would then mate two heterozygous brown mice (X+X-) containing the gene of
interest to produce a homozygous brown knockout mouse (X-X-) and screen by
southern blot.
Where in the genome are loxP sites located in a Cre/Lox model?
a. Adjacent to the Cre locus expressed in a desired cell type
b. On either side of the gene that is to be knocked out
c. Random sites throughout the genome - ANSWER b. On either side of the
gene that is to be knocked out
In which organism was the CRISPR system discovered? - ANSWER System of
bacterial natural immunity. From studying natural immunity in bacteria.
In the immunization phase, what happens to the foreign viral DNA? - ANSWER
Phase 1(immunization phase): how the bacterial cell makes itself immune
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) | GRADED A+ |
LATEST UPDATE 2025-2026
What is the meaning of the term transgenic? - ANSWER A transgenic organism
is one whose genome has been altered by the random introduction of a foreign
piece of DNA. Researchers often compare transgenic organisms to wild type or
control organisms to determine the effect the transgene has. The amount of DNA
inserted can vary from 1-200 base pairs
When determining if an additional copy of a gene added to a mouse genome
using PCR, how would you be able to distinguish between the endogenous gene
and the transgene? - ANSWER For PCR, I use two primers, one inside the
transgene and one outside the transgene, so I can distinguish the endogenous
gene from the transgene. Since only the transgene can bind with these two
primers and be amplified.
When determining if an additional copy of a gene added to a mouse genome
using a Southern blot, how would you be able to distinguish between the
endogenous gene and the transgene? - ANSWER Like PCR, I will use one probe
to target the gene and another probe to target the vector in Southern Blot. When
there is only one band with the size of the gene, then it is an endogenous gene. If
there are two bands, one is with the size of the gene, another is the size of the
vector, and it is the transgene.
What would be the purpose of creating a reporter gene as a transgene? What
types of experimental questions might you be able to ask and answer? -
ANSWER Reporter genes are used to investigate the expression of other genes
,whose expression we need to measure in a transgenic animal. Reporter genes
"report" whether the gene of interest is expressed or not, or the location of gene
expression.
In the lecture, the example of the HKβ subunit gene is given, in which using a
reporter gene, scientists want to investigate the location of expression of the HKβ
subunit gene in the tissues of a transgenic mouse. LacZ gene is used as a reporter
and the HKβ control region is placed in front of the LacZ gene in a plasmid vector.
Now the tissues that expressed the HKβ subunit gene also expressed the reporter
LacZ gene and it became easier for the scientists to locate the expression of the
HKβ subunit gene because of the blue color of the tissues, expressed by the LacZ
gene whose product is β-galactosidase.
Other reporter genes mentioned in the textbook include the luciferase gene from
firefly and the bacterial gene cat that encodes chloramphenicol acetyl transferase
enzyme (CAT).
When creating a knockout animal, why do you need to engineer ES cells? -
ANSWER **Able to perform manipulation of the genome but the cells still
grow into a whole organism. ES cells give rise to all body tissue types. iPS cells:
take cells that are differentiated and cause them too undifferentiated.
**ES cells = pluripotent, used to knock out genes of interest.
When creating knockout ES cells, why do you need to isolate cells that are
sensitive to G418 AND ganciclovir? - ANSWER To tell you where your
transgene is being expressed!
, G418 neomycin analog kills cell without neomycin-resistance gene (cells with no
integration)
Gangcyclovir kills cells containing thymidine kinase gene (cells with non-specific
recombination)
Cells that grow on medium will have homologous recombination between the
plasmid and WT gene
When creating a knockout mouse, the chimeric animal is mated with one that is
black and normal for the gene of interest. From this cross, three possible offspring
can be produced. Explain the genetics of each of the three and what you would do
next with the desired offspring. - ANSWER possible progeny genomes include:
A/X+ (brown, no gene of interest), A/X- (brown, gene of interest), a/X+ (black, no
gene of interest) in which A/X- is the most desirable genome.
I would then mate two heterozygous brown mice (X+X-) containing the gene of
interest to produce a homozygous brown knockout mouse (X-X-) and screen by
southern blot.
Where in the genome are loxP sites located in a Cre/Lox model?
a. Adjacent to the Cre locus expressed in a desired cell type
b. On either side of the gene that is to be knocked out
c. Random sites throughout the genome - ANSWER b. On either side of the
gene that is to be knocked out
In which organism was the CRISPR system discovered? - ANSWER System of
bacterial natural immunity. From studying natural immunity in bacteria.
In the immunization phase, what happens to the foreign viral DNA? - ANSWER
Phase 1(immunization phase): how the bacterial cell makes itself immune
