Control of Gene Expression (Final) Flashcards
The Hawaiian bobtail squid (Euprymna scolopes) is able to glow from luminescent Vibrio fischeri bacteria held in its light organs. The bacteria glow in response to a molecule that regulates the expression of genes involved in light-producing chemical reactions. The regulator controls the production of the genes’ mRNA. Therefore, the light-producing genes are under:
a
transcriptional control
b
translational control
c
post-translational control
a
transcriptional control
In the lac operon, when would RNA polymerase not transcribe the galactoside permease and β-galactosidase genes? (choose all that apply)
a
In the absence of the repressor protein
b
In the presence of lactose
c
If the operator sequence had been edited out with gene-editing technology
d
If the promotor sequence had been edited out with gene-editing technology
e
If the gene for the repressor was mutated such that the repressor no longer bound to lactose
d
If the promotor sequence had been edited out with gene-editing technology
e
If the gene for the repressor was mutated such that the repressor no longer bound to lactose
Which of the following correctly identifies a difference between the lac operon and the trp operon?
a
The trp operon only controls the expression of one gene, as opposed to multiple genes being controlled by the lac operon
b
The trp operon is under positive control whereas the lac operon is under negative control
c
The trp operon does not have an operator, unlike the lac operon
d
Since the trp operon controls genes that build a molecule, that molecule (tryptophan) works as a co-repressor, helping the repressor stay bound to the operator. Lactose, on the other hand, makes the repressor unable to bind to the operator
e
None of the above are real differences between the trp and lac operons
d
Since the trp operon controls genes that build a molecule, that molecule (tryptophan) works as a co-repressor, helping the repressor stay bound to the operator. Lactose, on the other hand, makes the repressor unable to bind to the operator
An epigenetic change in gene expression will involve a change in the nucleotide sequence of a gene, true or false?
a
True
b
False
b
False
There are two types of twins, one type of twins is formed from two different sets of egg and sperm forming two separate embryos, whereas the other type of twins is formed when a single embryo splits in two. In the type of twins that were originally one embryo, the _______ is/are mostly the same between the two twins throughout their lives, but the _______ diverge more and more the longer the twins are alive.
a
nucleotide sequence of genes; epigenetic markers on genes/histones
b
epigenetic markers on genes/histones; nucleotide sequence of genes
c
Neither a or b are true because the nucleotide sequence of genes and the epigenetic markers stay the same throughout the twin’s lives
d
Neither a or b are true because the nucleotide sequence of genes and the epigenetic markers both change markedly throughout twin’s lives
a
nucleotide sequence of genes; epigenetic markers on genes/histones
A researcher found a method she could use to manipulate and quantify epigenetic tags in embryonic cells in culture. In one set of experiments, she succeeded in increasing acetylation of histone proteins. Which of the following results would she most likely see? (choose two answers)
a
decreased chromatin condensation
b
increased chromatin condensation
c
no effect on chromatic condensation
d
decreased transcription
e
increased transcription
f
no effect on transcription
a
decreased chromatin condensation
e
increased transcription
Epigenetic changes:
a
Are wiped clean with every DNA duplication
b
Are wiped clean between every new generation
c
Are mostly wiped clean every new generation, but some are preserved between generations
d
Are sometimes wiped clean every new generation, but most are preserved between generations
e
Are rarely wiped clean between generations
c
Are mostly wiped clean every new generation, but some are preserved between generations
Epigenetics is a factor in the development of some cancers. Remember that epigenetic changes can make specific genes more or less accessible to being expressed. Based on the three different types of genes that affect cancer that we’ve talked about (proto-oncogenes, tumor suppressor genes, and mutator genes), which would increase cancer risk if epigenetic changes made them more accessible?
a
Proto-oncogene
b
Tumor suppressor gene
c
Mutator gene
d
Two of the above
e
All of the above
a
Proto-oncogene
A child with Angelman syndrome may have DNA that was not correctly imprinted. Concerning genetic imprinting, which of the following accurately describes how it usually occurs and how Angelman syndrome differs from typical imprinting?
a
In most people, the majority of genes are imprinted. In Angelman syndrome, very few are.
b
Most people have one working copy of each imprinted gene and the other is silenced. In Angelman syndrome, both copies of a gene are silenced, leaving no working copies of the gene
c
In most people, imprinting makes both copies of the imprinted genes more accessible to transcription/translation. In Angelman syndrome, the two copies of the imprinted genes are less accessible
d
Imprinting of genes normally happens early on in the embryo. In Angelman syndrome, it happens later
b
Most people have one working copy of each imprinted gene and the other is silenced. In Angelman syndrome, both copies of a gene are silenced, leaving no working copies of the gene
How does a microRNA (miRNA) recognize a specific target mRNA?
a
A miRNA can recognize a specific target due to different RISC proteins binding it to the target.
b
A miRNA can recognize a specific target by binding to the hairpin-containing precursor on the target.
c
A miRNA can recognize a specific target whenever it can form complementary base pairs with the target.
d
A miRNA can recognize a specific target by binding to the TATA box of the target.
c
A miRNA can recognize a specific target whenever it can form complementary base pairs with the target.
