What features of eukaryotes provide additional opportunities for the regulation of gene expression compared to bacteria?
-separated processes of transcription and translation
-presence of chromatin
-opportunity for posttranscriptional and pre-translational regulation
What are the two different types of histone modifications and how do they impact transcription?
Present an overview of the manner in which chromatin can be remodeled. Describe the manner in which these remodeling processes influence transcription.
How might one determine the influence of CAAT boxes on the transcription rate of a given gene?
All of the above would be good ways to determine the influence of CAAT boxes on transcription rate.
Describe the manner in which activators and repressors influence the rate of transcription initiation.
Activators and repressors change the relationship of RNAP II to the transcription complex.
How might chromatin structure be involved in such regulation?
DNA loops are thought to bring distant enhancer or silencer elements into proximity with promoter regions of the genes under their regulation.
Choose the types of alternative splicing patterns with the correct description of how they lead to the production of different protein isoforms.
-Cassette exons??whole exons are excluded from the mature message, resulting in a protein that is missing certain sequences (perhaps an entire protein domain).
-Alternative polyadenylation??produces messages with different 3?3? coding sequences as well as
Explain how the use of alternative promoters and alternative polyadenylation signals produces mRNAmRNAs with different 5? and 3? ends.
Which statements about the modification of chromatin structure in eukaryotes are true?
-Acetylation of histone tails is a reversible process.
-Some forms of chromatin modification can be passed on to future generations of cells.
-DNA is not transcribed when chromatin is packaged tightly in a condensed form.
-Acetylation of histone tails in
The diagram below shows two stretches of DNA in the genome of an imaginary eukaryotic cell. The top stretch of DNA includes the fantasin gene, along with its promoter and one of its enhancers. The bottom stretch of DNA includes the imaginin gene, its prom
-The fantasin gene will be transcribed at a high level when activators specific for control elements A, B, and C are present in the cell.
-Control elements C, D, and E are distal control elements for the imaginin gene.
-Both the fantasin gene and the imag
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Consider the predominant types of alternative splicing events that occur in mammals. Which of the following choices represent mRNA molecules that could be produced from the primary RNA transcript by alternative RNA splicing? (In each choice, the yellow pa
Explain how these classes of enzymes are critical to initiating mRNA decay.
-Decapping enzymes function in both deadenylation-dependent and -independent decay, by removing the 5? cap and allowing XRN1 exonuclease degradation.
-Deadenylases, which function in deadenylation-dependent decay, shorten the 3?-poly-AA tail and lead to t
Explain how RNAi is both "potent and specific.
-Gene silencing occurs in a sequence-specific manner since RNAi depends on complementary base pairing.
-RNAi is considered potent because only a few molecules are needed to degrade large amounts of mRNA.
How does the silencing process begin, and what major components participate?
RNAi may be directed by small interfering RNARNAs (siRNAs) or microRNAs (miRNAs); how are these similar, and how are they different?
How might this work?
How and why are eukaryotic mRNAs transported and localized to discrete regions of the cell?
-Because of mRNA transportation each component of a cell is unique.
-mRNA transport is dependent on motor proteins, which "walk" along microtubules of the cytoskeleton.
-mRNA localization is dependent on the binding with RBPs.
How may the covalent modification of a protein with a phosphate group alter its function?
There is no general "rule" describing the absolute effect of phosphorylation on the function of the protein.