Control of gene expression in eukaryotic cells occurs at which level(s)?
- only the transcriptional level
- epigenetic and transcriptional levels
- epigenetic and transcriptional and translational levels
- epigenetic and transcriptional, translational, and post-translational levels
What do figures X and Y in the graphic illustrate?
- Transcription and translation in a eukaryotic cell (figure X) and a prokaryotic cell (figure Y).
- Transcription and translation in a prokaryotic cell (figure X) and a eukaryotic cell (figure Y).
- Transcription in a eukaryotic cell (figure X) and translation in a prokaryotic cell (figure Y).
- Transcription in a prokaryotic cell (figure X) and translation in a eukaryotic cell (figure Y)
If glucose is absent but lactose is present, the lac operon will be:
- partially activated
What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator?
- In the presence of lactose, the lac operon will not be transcribed.
- In the absence of lactose, the lac operon will be transcribed.
- The cAMP-CAP complex will not increase RNA synthesis.
- The RNA polymerase will not bind the promoter.
What would happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator?
- In the absence of tryptophan, the genes trpA-E will not be transcribed.
- In the absence of tryptophan, only genes trpE and trpD will be transcribed.
- In the presence of tryptophan, the genes trpA-E will be transcribed.
- In the presence of tryptophan, the trpE gene will not be transcribed.
What are epigenetic modifications?
- the addition of reversible changes to histone proteins and DNA
- the removal of nucleosomes from the DNA
- the addition of more nucleosomes to the DNA
- mutation of the DNA sequence
Which of the following statements about epigenetic regulation is false?
- Histone protein charge becomes more positive when acetyl groups are added.
- DNA molecules are modified within CpG islands.
- Methylation of DNA and histones causes nucleosomes to pack tightly together.
- Histone acetylation results in the loose packing of nucleosomes.
Which of the following is true of epigenetic changes?
- They only allow gene expression.
- They allow movement of histones.
- They change the DNA sequence.
- They are always heritable.
The binding of what is required for transcription start?
- a protein
- DNA polymerase
- RNA polymerase
- a transcription factor
What would be the outcome of a mutation that prevented DNA binding proteins from being produced?
- decreased transcription because transcription factors would not bind to transcription binding sites
- decreased transcription because enhancers would not be able to bind to transcription factors
- increased transcription because repressors would not be able to bind to promoter regions
- increased transcription because RNA polymerase would be able to increase binding to promoter regions
What will result from the binding of a transcription factor to an enhancer region?
- decreased transcription of an adjacent gene
- increased transcription of a distant gene
- alteration of the translation of an adjacent gene
- initiation of the recruitment of RNA polymerase
Which of the following are involved in post-transcriptional control?
- control of RNA splicing
- proteolytic cleavage
Gene A is thought to be associated with color blindness. The protein corresponding to gene A is isolated. Analysis of the protein recovered shows there are actually two different proteins that differ in molecular weight that correspond to gene A. What is one reason why there may be two proteins corresponding to the gene?
- One protein had a 5’ cap and a poly-A tail in its mRNA, and the other protein did not.
- One protein had a 5’ UTR and a 3’ UTR in its RNA, and the other protein did not.
- The gene was alternatively spliced.
- The gene produced mRNA molecules with differing stability.
Binding of an RNA binding protein will change the stability of the RNA molecule in what way?
- neither increase nor decrease
- either increase or decrease
A mutation in the 5’UTR that prevents any proteins from binding to the region will:
- increase or decrease the stability of the RNA molecule
- prevent translation of the RNA molecule
- prevent splicing of the RNA molecule
- increase or decrease the length of the poly-A tail
Post-translational modifications of proteins can affect which of the following?
- mRNA splicing
- chemical modifications
A mutation is found in eIF-2 that impairs the initiation of translation. The mutation could affect all but one of the following functions of eIF-2. Which one would not be affected?
- The mutation prevents eIF-2 from binding to RNA.
- The mutation prevents eIF-2 from being phosphorylated.
- The mutation prevents eIF-2 from binding to GTP.
- The mutation prevents eIF-2 from binding to the 40S ribosomal subunit.
The addition of a ubiquitin group to a protein does what?
- increases the stability of the protein
- decreases translation of the protein
- increases translation of the protein
- marks the protein for degradation
What are cancer-causing genes called?
- transformation genes
- tumor suppressor genes
Targeted therapies are used in patients with a certain gene expression pattern. A targeted therapy that prevents the activation of the estrogen receptor in breast cancer would be beneficial to what type of patient?
- patients who express the EGFR receptor in normal cells
- patients with a mutation that inactivates the estrogen receptor
- patients with over-expression of ER alpha in their tumor cells
- patients with over-expression of VEGF, which helps in tumor angiogenesis
In a new cancer treatment, a cold virus is genetically modified so that it binds to, enters, and is replicated in cells, causing them to burst. The modified cold virus cannot replicate when wildtype p53 protein is present in the cell. How does this treatment treat cancer without harming healthy cells?
- The modified virus only infects and enters cancer cells.
- The modified virus replicates in normal and cancer cells.
- The modified virus only infects and enters normal cells.
- The modified virus replicates only in cancer cells.
A drug designed to switch silenced genes back on in cancer cells would result in what?
- prevent methylation of DNA and deacetylation of histones
- prevent methylation of DNA and acetylation of histones
- prevent deacetylation of DNA and methylation of histones
- prevent acetylation of DNA and demethylation of histones
What are positive cell-cycle regulators that can cause cancer when mutated called?
- transformation genes
- tumor suppressor genes
- mutated genes