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| 1 | |
Repressible operons are typically involved in ________ and inducible operons are typically involved in ________. |
| | A) | transcription; translation |
| | B) | eukaryotes; prokaryotes |
| | C) | prokaryotes; eukaryotes |
| | D) | catabolism; anabolism |
| | E) | anabolism; catabolism |
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| 2 | |
Chromatin is composed of: |
| | A) | nucleic acid. |
| | B) | protein. |
| | C) | carbohydrate. |
| | D) | (1) and (2) |
| | E) | (1), (2) and (3) |
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| 3 | |
Which one of the following statements about the regulation of gene expression in eukaryotes is incorrect? |
| | A) | Chromatin in the closed conformation is more easily transcribed than chromatin in the open conformation. |
| | B) | Acetylated histones do not bind as tightly to DNA as non-acetylated histones. |
| | C) | ATP-dependent chromatin remodeling enzymes can be recruited to a site of transcription by activator proteins. |
| | D) | Steroid hormone receptor molecules often function as transcriptional activators. |
| | E) | All of the above statements about the regulation of gene expression in eukaryotes are correct. |
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| 4 | |
Which one of the following is NOT a common motif for DNA binding proteins? |
| | A) | leucine zipper |
| | B) | The homeodomain motif |
| | C) | disulfide bridge |
| | D) | zinc finger |
| | E) | helix-turn-helix |
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| 5 | |
True or False: DNA methylation typically enhances the expression of a eukaryotic gene. |
| | A) | True |
| | B) | False |
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| 6 | |
Which one of the following statements about alternative splicing is correct? |
| | A) | Alternative splicing leads to different protein products with very different functions. |
| | B) | Alternative splicing enables an organism to increase the size of its genome without having to increase the size of its proteome. |
| | C) | Alternative splicing is common in all eukaryotes, but uncommon in prokaryotes. |
| | D) | Alternate forms of a protein are made by different cell types, or at different stages of development, from a single gene in the genome. |
| | E) | All of the above statements about alternative splicing are correct. |
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| 7 | |
Which one of the following statements about RNA interference is incorrect? |
| | A) | RNA interference is an example of genetic regulation at the level of transcription. |
| | B) | Precursor miRNAs form a hairpin loop and are then hydrolyzed by dicer. |
| | C) | MiRNAs associate with cellular proteins and then bind to target sequences in mRNA. |
| | D) | In animals, RISC inhibits translation. |
| | E) | In plants, RISC targets a mRNA for degradation. |
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| 8 | |
Which of the following is an example of positive regulation? |
| | A) | Binding of the lac repressor to the operator of the lac operon. |
| | B) | Binding of the trp repressor to the operator of the trp operon. |
| | C) | Binding of the CAP-cAMP complex near the promoter of the lac operon. |
| | D) | Both a and b are examples of positive regulation. |
| | E) | None of the above is an example of positive regulation. |
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| 9 | |
Why is it that enhancers can activate a gene which is distant to its position on a chromosome? |
| | A) | They modify the structure of RNA polymerase, which is free to diffuse in the direction of the gene which will be activated. |
| | B) | They collect repressor proteins which promote transcription, then are able to contact the initiation complex (to which RNA polymerase II is bound), stimulating transcription. |
| | C) | Enhancers are proteins which stimulate transcription, and can move throughout the nucleoplasm. |
| | D) | Regions of DNA far distant from an actual gene are catalytic, and can create end-products which activate RNA polymerase II. These end-products accumulate until there is sufficient activation for transcription to occur. |
| | E) | DNA bends to form a loop, positioning the enhancer closer to the promoter. |
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| 10 | |
How do nucleosomes influence gene expression in a eukaryotic cell? |
| | A) | Transcription factors and RNA polymerase II cannot identify and bind the promoter. |
| | B) | They promote methylation of certain bases in DNA which causes the gene to "turn off". |
| | C) | They eliminate denaturation of DNA, which is required to generate template strands for transcription. |
| | D) | Nucleosomes move the promoter so that it no longer is next to the coding sequence of the gene. |
| | E) | Transcription factors are absorbed by nucleosomes, rendering them nonfunctional. |
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| 11 | |
What happens to ubiquitin after the protein to which it was attached is processed by the proteasome? |
| | A) | It is used to restore the carboxyl ends of the constituent amino acids so they can be recycled. |
| | B) | It becomes available to ubiquitin ligase to mark another protein for destruction. |
| | C) | The ubiquitin is phosphorylated to restore energy to the proteasome. |
| | D) | Ubiquitin helps amino acids bind to aminoacyl tRNA synthetase in order to boost cellular levels of the various charged tRNA molecules. |
| | E) | Ubiquitin is recycled by digestion in a peroxisome and assemblage by the endoplasmic reticulum. |
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| 12 | |
A DNA-binding motif is |
| | A) | a part of RNA polymerase that recognizes a promoter. |
| | B) | a catalytic region of an enzyme which can identify specific parts of a gene and promote chemical reactions which lead to gene expression. |
| | C) | a particularly-shaped portion of a polypeptide which fits binds with DNA so that it can interact with a specific sequence of nucleotides. |
| | D) | part of the ribosome large subunit. |
| | E) | part of the ribosome small subunit. |
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| 13 | |
In an operon, the region termed an "operator" has the job of |
| | A) | attracting RNA polymerase to increase transcription. |
| | B) | binding to an effector to demonstrate the presence of a metabolite. |
| | C) | prevent or decrease the initiation of transcription. |
| | D) | inducing transcription of the genes which follow. |
| | E) | preventing ribosome association with an mRNA molecule. |
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| 14 | |
General transcription factors are required for the majority of eukaryotic transcription events. |
| | A) | True |
| | B) | False |
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| 15 | |
Which of the following is/are associated with inactivation of eukaryotic genes? |
| | A) | Deacetylation of histones |
| | B) | Methylation of bases in the genes to be deactivated. |
| | C) | Binding of proteins which are attracted to clusters of 5-methylcytosine. |
| | D) | Chromatin remodeling |
| | E) | All of the above can inactivate eukaryotic genes. |
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