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18 Cards in this Set
- Front
- Back
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What is an enhancer?
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A DNA sequence located upstream or downstream from a promoter to which transcription factors bind.
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What is the function of transcription factors?
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Interact with RNA polymerase situated on the promoter to initiate transcription.
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What makes RNA different from DNA?
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1) OH at 2' position on ribose
2) Uracil |
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What affects initiation of transcription?
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Promoters, enhancers, and transcription factors
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What enzymes synthesize RNA in eukaryotes?
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RNA polymerases
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What is the function of the 5' cap?
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1) Enhances translation
2) Prevents mRNA degradation |
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What is the function of the poly-A tail?
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1) Stabilizes mRNA
2) Enhances translation |
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What is the function of a consensus sequence?
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Determine where introns will be removed on RNA
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Where are snRNA's located?
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Spliceosome
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What is the function of snRNA?
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Recognize the consensus sequence through base complementation so introns can me cleaved from mRNA.
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What is the benefit of alternative splicing of pre-mRNA?
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1) Evolutionary diversity
2) Production of multiple types of proteins from the same pre-mRNA |
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How do spliceosomes know where to cleave the primary mRNA?
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snRNA's recognize the consensus sequence
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What are the pros and cons for using consensus sequences but not strictly conserved sequences for splicing?
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Pros:
1) Flexibility of selection of splicing sites Cons: 1) Generates errors amplified by mutations 2) Not enough conserved sequences to be used |
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Name some ways can eukaryotic mRNA's be modified post-transcriptionally...?
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5' cap, poly(A) tail, splicing, and editing
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What are some common inhibitors of transcription?
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Actinomycin D and Rifampicin
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What is the function of Actinomycin D?
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Inhibits transcription in eukaryotes and prokaryotes by intercalating itself into DNA.
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What is the function of Rifampin?
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Inhibits transcription in prokaryotes by inhibiting initiation.
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What is the general trend regarding RNA stability as the level of complexity of organisms increases?
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RNA becomes more stable with increased organism complexity.
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