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57 Cards in this Set
- Front
- Back
1. In some organisms, the primary function of a gene in a cell is to participate in regulating the body as a whole rather than responding to the cell's immediate environment. These organisms would be |
A. multicellular. |
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2. The maintenance of a constant environment in a cell is called __________. |
B. homeostasis |
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3. Through control of gene expression, a bacterial cell responds to changing __________ conditions. |
C. environmental |
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4. In multicellular organisms, the mechanism most directly responsible for directing development and maintaining homeostasis is gene |
D. regulation. |
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5. Eukaryotic cell mRNA transcripts can remain in the cell for hours because they are |
A. stable. |
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6. As a microbiologist you have been asked to investigate gene regulation in a new bacteria. Given what is known about bacteria, the logical place to begin your investigation is |
A. transcriptional control. |
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7. Transcriptional control-proteins increase the rate of transcription by binding to |
E. enhancer sequences within the DNA. |
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8. You have been asked to design a synthetic DNA motif, able to bind proteins to regulate specific genes. The location on this motif that you would necessarily design for protein binding is the |
B. major groove of the DNA double helix. |
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9. Vertebrate cells possess a protein that binds to clusters of 5-methylcytosine and ensures the gene will stay in the "off" position. This control of gene regulation is a result of |
C. methylation. |
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10. You lead a research team challenged with the task of creating a regulatory protein able to shut off transcription. You focus your design around a binding site called an operator that is associated with the promotor. The physical location of the operator most likely to affect transcription would be |
B. downstream of the gene promoter. |
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11. Histones that are tightly wound by DNA and are the basic unit of chromatin are called |
B. nucleosomes. |
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12. The hallmark of multicellular organisms is their ability to |
C. maintain homeostasis. |
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13. Enhancers are the binding sites for the |
E. specific transcription factors. |
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14. Within its core a nucleosome contains ____ histones. |
D. 8 |
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15. The basic tool of genetic regulation is the ability of certain proteins to bind to specific |
B. regulatory DNA sequences. |
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16. In vertebrates, DNA methylation - the addition of a methyl group to DNA nucleotides - ensures that |
E. once a gene is turned off, it will remain off. |
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17. You belong to a pharmaceutical company that designs small RNAs, able to control expression of genes that cause chronic illness. The primary focus area of your research should be |
C. translational repression. |
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18. Although the specific mechanism of RNA interference has not been fully defined, it involves |
A. double stranded RNA interference with mRNA. |
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19. The DNA-binding proteins of almost all regulatory proteins use one of a small set of shapes that enable them to fit into the DNA major groove. These shapes are called |
A. structural motifs. |
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20. Small RNAs can regulate gene expression. One type, called micro RNA (miRNA), acts by binding directly to |
A. mRNA to prevent translation. |
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21. The lac operon regulatory system is important to bacteria primarily because lactose |
C. is only rarely available; producing enzymes all the time is costly. |
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22. In eukaryotes, specific transcription factors have two distinct domains: |
B. a DNA-binding domain and an activation domain. |
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23. In order for transcription to be initiated |
B. RNA polymerase must have access to the DNA double helix and must also be capable of binding to the gene's promoter. |
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24. Certain proteins can bind to specific DNA regulatory sequences by entering |
A. the major groove of the DNA and reading the nucleotide base pairs. |
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25. Regulatory proteins can identify specific sequences on the DNA double helix without unwinding the helix. This is accomplished by inserting |
E. DNA-binding motifs into the major groove of the double helix where the edges of the nitrogen bases protrude. |
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26. When E. coli cells produce the amino acid tryptophan, a cluster of five genes is transcribed together. This cluster of genes is referred to as the |
D. trp operon. |
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27. The proteins necessary for the use of lactose in E. coli are collectively called the |
C. lac operon. |
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28. A defining characteristic of eukaryotic organisms is that they |
B. have their transcription occurring in the nucleus and translation in the cytoplasm. |
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29. The primary transcripts in eukaryotes are most accurately described as |
C. a faithful copy of the entire gene including exons and introns. |
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30. One of the DNA-binding motifs in many eukaryotic organisms that contains a nearly identical sequence of 60 amino acids is known as the |
D. homeodomain. |
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31. The most common DNA-binding motif is the |
E. helix-turn-helix. |
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32. A protein that regulates transcription by binding to the operator is known as the |
B. repressor. |
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33. A protein that initiates gene transcription and allows for non-glucose molecules to be used is |
E. CAP. |
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34. A cluster of functionally-related genes that are regulated together and encoded into a single mRNA molecule is called a(n) |
A. operon. |
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35. A site of negative genetic regulation where binding by repressor blocks transcription is the |
D. operator. |
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36. A site at the 5' end of a gene where RNA polymerase attaches to initiate transcription is called a(n). |
C. promoter. |
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37. The enzyme b-galactosidase acts on lactose to form galactose. In turn, the presence of galactose leads to expression of the enzymes responsible for the metabolism of galactose. In this case, lactose is serving as a carbon source and as a(n) |
A. inducer. |
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38. The lactose analog isopropyl-b-D-thio-galactoside (IPTG) is often used to regulate gene expression systems in bacteria. IPTG does not act as a substrate for b-galactosidase, but can bind to, and inactivate, the repressor. In this case, IPTG serves as a(n) |
A. inducer. |
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39. The main form of glucose repression in the lac operon is |
C. inducer exclusion. |
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40. If you were given a sequence with a mutation in the -35 region of the trp operon the most likely effects would be the |
A. interference with RNA polymerase binding to the promotor. |
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41. You are studying regulation of a prokaryotic operon. Experimental results show that expression of the operon is increased when product levels are low. Based on this information, you conclude that the likely mode of regulation is |
B. the operon is OFF in the absence of its regulatory protein. |
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42. The binding of TFIID is followed by the binding of a number of other general transcription factors. The correct order of binding of these factors would be |
B. TFIIB-TFIIA, TFIIF, TFIIE, TFIIH, TFIIJ |
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43. Your research project involves the characterization of a recently identified transcription factor. As part of your project, you want to determine if this transcription factor binds directly to any of the general transcription factors. Unfortunately, however, you are having trouble expressing and purifying the full length protein. An option that may help you achieve your research goal would be to |
D. try to express and purify only the activation domain, since transcription domains can be separated. |
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44. You are working to identify enhancer regions of a particular gene. The best place to begin your search is |
C. primarily upstream of the promoter; distance from the promoter does not matter. |
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45. The progesterone receptor (PR) is a steroid hormone receptor and transcription factor. The protein SRC-1, which does not bind DNA by itself, can bind to PR and increase expression of genes regulated by PR. Based on this information, SRC-1 is a(n) |
A. coactivator. |
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46. The TFIID complex is formed by |
A. TATA-binding protein TBP and TAFs. |
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47. The p300/CBP (CREB-binding protein) coactivator proteins are histone acetyltransferases that help regulate the transcription of many genes. Based on this information you can conclude that these proteins are involved in |
B. chromatin remodeling. |
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48. DNA methylation is the only known natural modification of DNA. It affects |
C. cytosine bases. |
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49. If you were able to look very closely at a portion of DNA and find methylated histones, you would |
C. be looking at a region of inactive chromatin. |
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50. Elucidation of the histone code might |
A. allow us to turn specific genes on or off. |
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51. You are studying the function of a recently identified gene in C. elegans. You perform genetic screens for several months in an attempt to isolate loss-of-function gene mutations, but your efforts are unsuccessful. Your advisor suggests you try another approach to eliminate gene function. The best technique to accomplish this goal would be |
D. use RNA interference to prevent mRNA translation. |
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52. The enzyme dicer chops dsRNA molecules into small pieces of |
B. miRNA and siRNA. |
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53. The gene encoding apolipoprotein B exists in two isoforms, APOB100 and APOB48. These two forms are produced as a result of |
C. RNA editing. |
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54. Production of the iron-storing protein ferritin is regulated by aconitase, which binds to a 30-nucleotide sequence at the beginning of the ferritin mRNA and interferes with ribosome binding. Aconitase must be a |
B. translation repressor protein. |
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55. What is the difference between a gene that is derepressed and one that is induced? |
A. A gene that is derepressed is turned on because a repressor molecule is absent. By comparison, a gene that is induced is turned on because an inducer molecule is present. |
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57. You have discovered a way to damage proteins associated with initiating over-active inflammatory responses. You must now begin a study on the pathway that follows the clean up of those damaged proteins. Where would your study be focused? |
B. Tagging of the protein with ubiquitin and then proteolysis of the protein by proteases in the proteasomes. |
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58. You are studying the affects of transcription factors on the activation of gene expression. However, when first starting your study you notice that some of the transcription factors bind further away from the DNA that it is aiming to transcribe. What description best explains this? |
C. DNA looping transports the transcription factor closer to the promoter and initiates gene transcription. |