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Cell Bio Exam 3 Chapter 8
Terms in this set (15)
Which of these statements about microRNAs and siRNAs is NOT true?
A. They both target RNA
B. They both use single-stranded RNAs to target C. They both use RISC
D. They both use endogenous (the cell's own) RNAs to generate short RNA fragments
In bacteria, the translation repressor protein A.Binds the translation start site and prevents translation
B. Binds the translation start site and assists with starting translation
C. Translates mRNAs
D. Binds to the stop codon and helps to repress translation from going on too far
What is the average half-life of an mRNA?
A. A few days
B. About 10 hours
C. Less than 30 minutes
D. Less than 15 seconds
How might cells ensure inheritance of epigenetic marks such as cytosine methylation and histone modifications?
A.They are not inherited, they are established do novo (newly) in each generation.
B. A copy of parental chromatin is inherited by each of the daughter cells and the pattern is replicated on the newly synthesized chromatin.
C. There is currently, no satisfactory explanation for this phenomenon
D. Only one daughter cell receives the original set of marks. The other cell creates the pattern anew.
How does a Master Transcription Factor exert control of cell identity?
A.Through establishing a positive feedback loop, where it expresses more of itself.
B. Through establishing a negative feedback loop, where it expresses more of itself.
C. There is no such thing as a Master Transcription Factor
D. Through re-establishing progenitor identity to create more stem cells.
You are a Scientist and are contacted by a patient who is need of a new liver after theirs was damaged in an accident. This patient, due to a unique mutation, is unable to receive a donor organ. How might you help this person?
A. Take their skin cells, provide the cells with oct4, sox2, and klf4 to de-differentiate them into iPS cells, then differentiate those into new liver cells to repair the damage to their liver or replace it completely.
B. Take their skin cells, provide the cells with microRNAs to de-differentiate them into iPS cells, then differentiate those into new liver cells to repair the damage to their liver or replace it completely.
C. They cannot be helped with the information we have learned in this class.
D.Take their skin cells, provide the cells with chromatin remodeling complexes to de-differentiate them into iPS cells, then differentiate those into new liver cells to repair the damage to their liver or replace it completely.
How can we generate many different cell types, using only a few regulatory factors?
A. Through addition of transcription factors
B. Through addition of microRNAs
C. Through addition of chromatin modifying complexes
D. Through addition of chromatin remodeling complexes
How can eukaryotes activate many genes at once?
A. Inclusion of the same transcription factor binding site in the promoter of multiple genes will allow activation of them all at once in response to that transcription factor
B. Eukaryotes only have one gene per promoter, so they do not activate many genes at once
C. Eukaryotes use operons where many genes are placed under control of the same promoter. This allows activation of many genes at once.
D. None of the above
In Drosophila embryos the Eve gene is expressed in seven stripes. How is this accomplished?
A. The Eve promoter contains elements that respond to different transcription factors (or repressors) in each segment of the embryo. X B. The Eve gene is actually expressed everywhere but just at higher levels in the stripes
C. The Eve gene promoter is methylated in the stripe regions
D. The Eve gene promoter is methylated in regions outside of the stripes
The large protein complex which brings together enhancers and promoters is called
C. General transcription factors
D. Chromatin remodelers
In Eukaryotes, many transcriptional regulators participate in deciding at what level a gene should be expressed. This is called:
A. Combinatorial control
B. Transcriptional activation
C. Transcriptional silencing
Transcription factors can help activate genes by
A. Recruiting chromatin modifying complexes X B. Recruiting histone deacetylases to remove acetyl marks
C. Compacting chromatin locally
D. Transcription factors don't activate gene expression, other proteins do this job
Eukaryotic gene activators
A. Can activate genes from very far away
B. Can activate genes only within a close distance from the promoter
C. Can work downstream of genes
D. More than one of the above
The Lac Operon
A. Only uses an activator
B. Only uses a repressor
C. Uses an activator to ensure glucose is absent and a repressor to ensure lactose is present
D. Uses an activator to ensure lactose is present and a repressor to ensure glucose is absent
What experiment proves to us that differentiated cells still house same genome as the first cell that the organism was formed from?
A. Nuclear transplantation from differentiated cells into embryos can recreate an entire organism
B. Creation of iPS cells
C. Analysis of which transcription factors each cell type bears
D. Converting one cell type to another
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