UVA BIO 2100 - Exam 5 Questions and Answers
Question 1.
describe what iPSCs (induced pluripotent stem cells) are, how they can increase our
understanding of developmental biology, and their therapeutic potential, noting how they
may complement gene therapy approaches
Correct Answer: ipsc are stem cells from adults created by using cells like skin
cells, presented with a cocktail, these cells become less differentiated,
morphologically look similar to embryonic stem cells and express the same
proteins, could take these out of a person, specialize them for a certain tissues
and then put them back in? express all the same genes as embryonic,
Question 2.
Describe what a gene "knockout" organism is, common reasons for producing them, the
role of embryonic stem cells and powerful selection strategies in their production, what
chimeric animals are, and the role of breeding in producing homozygous gene KOs
Correct Answer: knockout- deliberately turning off the function go a gene, not
excising it but making it nonfunctional, produced to see what the function and
effect of certain genes is, harder to make because have to isolate the gene
wanted specific in terms of location, works with embryonic stem cells
(pluripotent) - have potential to become any cell in the body, 1st have to make
cells w one nonfunctional allele and then turn into animals, not to excise but to
exchange nonfunctional, clone b2 micro globulin, disrupt gene by adding
another in the middle of it, this gene is resistant to disease, add another gene
flanking it that is susceptibility to a gene, only some will incorporate at right
position, homologous recombination - similar sequences will swap, only regions
of homology will swap, but can expose to diseases and then only ones
incorporated will have resistance to drug and no susceptibility, then are left
with embryonic stems cells with one functional allele and one non functional,
these will be inserted into the embryo and uterus, will be chimeras, some cells
will have nonfunctional and some will have normal, same with their germ cells,
breeding 50/50 chance, if mate chimera with another heterozygous for the
allele, 25% will have homologous for the nonfunctional
Question 3.
Explain how "partial diploid" mutants provide evidence for negative control acting through
a combination of a protein (repressor) and a DNA sequence (operator)
Correct Answer: when one copy of wild type and one mutant, some appeared to
function correctly and some still made the enzymes when no lactose present
repressor protein- when one copy of the Lac I gene is there, the protein can be
synthesized and can move throughput the cell working at both the defective
copies operator and the normal copy DNA sequence operator - when one normal
copy and one defective, defective copy is still defective and will still continue to
sequence the enzymes, adding another operator will not change the function of
the first one
Question 4.
Explain which parts of CRISPR/Cas are typically being exploited to alter eukaryotic genes
and the required modification to Cas9
Page 1
, Correct Answer: modification to Cas9 is adding the sequence that targets it to
the nucleus, otherwise would float in cytosol and have no affect, Can 9 and
engineered target guide RNA for the specific gene being cut out have to reach
the nucleus, once the DNA gene sequence is cut out the normal processes of
eukaryotic DNA repair occur in eukaryotes, can be used in either cutting DNA
out or to change DNA, repair mechanisms include non-homologous end joining
can cause translocation, two random chromosome ends are joined, also
homology directed repair, one homologue serves as a template copy for the
other homologue
Question 5.
Describe what information the Southern, Northern, and Western blots provide
Correct Answer: Southern blots - tell if a certain DNA sequence is present in a
sample, specific DNA sequences Northern Blot - determines which cells produce
certain mRNAs, gene expression Western blots-separates proteins present using
antibodies, proteins present, disease diagnosis
Question 6.
explain how a protease can be used in vitro to detect protein translocation
Correct Answer: protease can be used in vitro, if it is a seceratory protein and
microsomes are included, the protein will be translocated into the ER lumen
where it will be protected from the protease and not cleaved, will remain same
length if it is non seceratory and non translocated the protease will cut up the
protein, causing it to exist in smaller fragments and travel further down
electrophoresis
Question 7.
Describe what a (conventional) transgenic organism is, reasons why they are made, and
why breeding is required to produce a "true-breeding" colony of transgenic animals, and
how transgenic organisms fundamentally differ from gene therapy recipients
Correct Answer: transgenic organism is adding a gene to another organism,
deliberately introducing a gene, this can determine info about normal function
in humans, also gives us understanding about human disease this gene will be
present in every cell whether it is expressed or not, you can choose the control
sequences, this gene has to be randomly integrated into a chromosome, so it
will be copied into all the daughter cells, random chromosome, not guarenteed
to be transferred, zygote is placed back in uterus of the female mouse, will be
both nontransgenic and transgenic offspring, animal will be hemizygous for the
allele so its offspring will have 50/50 chance of getting the trans gene, have two
breed two hemizygous and 25% will be homozygous, these offspring will inherit
the trans gene at the same location on the same chromosome of the parent,
breeding will give all transgenic offspring
Question 8.
• Explain what a "constitutive" mutant is
Correct Answer: constitutve mutant - lacks the regulation processes for the
expression of genes, the genes are expressed when don't need to be.
unregulated level of expression, produces enzymes/proteins in constant
amounts regardless of cell environments
Page 2
Question 1.
describe what iPSCs (induced pluripotent stem cells) are, how they can increase our
understanding of developmental biology, and their therapeutic potential, noting how they
may complement gene therapy approaches
Correct Answer: ipsc are stem cells from adults created by using cells like skin
cells, presented with a cocktail, these cells become less differentiated,
morphologically look similar to embryonic stem cells and express the same
proteins, could take these out of a person, specialize them for a certain tissues
and then put them back in? express all the same genes as embryonic,
Question 2.
Describe what a gene "knockout" organism is, common reasons for producing them, the
role of embryonic stem cells and powerful selection strategies in their production, what
chimeric animals are, and the role of breeding in producing homozygous gene KOs
Correct Answer: knockout- deliberately turning off the function go a gene, not
excising it but making it nonfunctional, produced to see what the function and
effect of certain genes is, harder to make because have to isolate the gene
wanted specific in terms of location, works with embryonic stem cells
(pluripotent) - have potential to become any cell in the body, 1st have to make
cells w one nonfunctional allele and then turn into animals, not to excise but to
exchange nonfunctional, clone b2 micro globulin, disrupt gene by adding
another in the middle of it, this gene is resistant to disease, add another gene
flanking it that is susceptibility to a gene, only some will incorporate at right
position, homologous recombination - similar sequences will swap, only regions
of homology will swap, but can expose to diseases and then only ones
incorporated will have resistance to drug and no susceptibility, then are left
with embryonic stems cells with one functional allele and one non functional,
these will be inserted into the embryo and uterus, will be chimeras, some cells
will have nonfunctional and some will have normal, same with their germ cells,
breeding 50/50 chance, if mate chimera with another heterozygous for the
allele, 25% will have homologous for the nonfunctional
Question 3.
Explain how "partial diploid" mutants provide evidence for negative control acting through
a combination of a protein (repressor) and a DNA sequence (operator)
Correct Answer: when one copy of wild type and one mutant, some appeared to
function correctly and some still made the enzymes when no lactose present
repressor protein- when one copy of the Lac I gene is there, the protein can be
synthesized and can move throughput the cell working at both the defective
copies operator and the normal copy DNA sequence operator - when one normal
copy and one defective, defective copy is still defective and will still continue to
sequence the enzymes, adding another operator will not change the function of
the first one
Question 4.
Explain which parts of CRISPR/Cas are typically being exploited to alter eukaryotic genes
and the required modification to Cas9
Page 1
, Correct Answer: modification to Cas9 is adding the sequence that targets it to
the nucleus, otherwise would float in cytosol and have no affect, Can 9 and
engineered target guide RNA for the specific gene being cut out have to reach
the nucleus, once the DNA gene sequence is cut out the normal processes of
eukaryotic DNA repair occur in eukaryotes, can be used in either cutting DNA
out or to change DNA, repair mechanisms include non-homologous end joining
can cause translocation, two random chromosome ends are joined, also
homology directed repair, one homologue serves as a template copy for the
other homologue
Question 5.
Describe what information the Southern, Northern, and Western blots provide
Correct Answer: Southern blots - tell if a certain DNA sequence is present in a
sample, specific DNA sequences Northern Blot - determines which cells produce
certain mRNAs, gene expression Western blots-separates proteins present using
antibodies, proteins present, disease diagnosis
Question 6.
explain how a protease can be used in vitro to detect protein translocation
Correct Answer: protease can be used in vitro, if it is a seceratory protein and
microsomes are included, the protein will be translocated into the ER lumen
where it will be protected from the protease and not cleaved, will remain same
length if it is non seceratory and non translocated the protease will cut up the
protein, causing it to exist in smaller fragments and travel further down
electrophoresis
Question 7.
Describe what a (conventional) transgenic organism is, reasons why they are made, and
why breeding is required to produce a "true-breeding" colony of transgenic animals, and
how transgenic organisms fundamentally differ from gene therapy recipients
Correct Answer: transgenic organism is adding a gene to another organism,
deliberately introducing a gene, this can determine info about normal function
in humans, also gives us understanding about human disease this gene will be
present in every cell whether it is expressed or not, you can choose the control
sequences, this gene has to be randomly integrated into a chromosome, so it
will be copied into all the daughter cells, random chromosome, not guarenteed
to be transferred, zygote is placed back in uterus of the female mouse, will be
both nontransgenic and transgenic offspring, animal will be hemizygous for the
allele so its offspring will have 50/50 chance of getting the trans gene, have two
breed two hemizygous and 25% will be homozygous, these offspring will inherit
the trans gene at the same location on the same chromosome of the parent,
breeding will give all transgenic offspring
Question 8.
• Explain what a "constitutive" mutant is
Correct Answer: constitutve mutant - lacks the regulation processes for the
expression of genes, the genes are expressed when don't need to be.
unregulated level of expression, produces enzymes/proteins in constant
amounts regardless of cell environments
Page 2
