Chap 16 Bio Exam 3

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. B. diploid. C. bacterial. D. prokaryotic.

2. The maintenance of a constant environment in a cell is called __________. A. active transport B. homeostasis C. gene expression D. translation

3. Through control of gene expression, a bacterial cell responds to changing __________ conditions. A. internal B. protein C. environmental D. genetic

4. In multicellular organisms, the mechanism most directly responsible for directing development and maintaining homeostasis is gene A. expression. B. duplication. C. deletion. D. regulation.

5. Eukaryotic cell mRNA transcripts can remain in the cell for hours because they are A. stable. B. long. C. isolated. D. analogous.

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. B. translational control. C. promoter control. D. repressor control. E. operator control.

7. Transcriptional control-proteins increase the rate of transcription by binding to A. mRNA sequences within the DNA. B. tRNA sequences within the DNA. C. operator sequences within the DNA. D. promoter sequences within the DNA. E. enhancer sequences within the DNA.

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 A. minor groove of the DNA double helix. B. major groove of the DNA double helix. C. outside groove of the DNA double helix. D. inside groove of the DNA double helix. E. hydrogen bonding groove of the DNA double helix.

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 A. translation. B. enhancer expression. C. methylation. D. promoter expression. E. operator suppression.

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 A. upstream of the gene promoter. B. downstream of the gene promoter. C. internal to the gene itself. D. internal to the gene promoter.

11. Histones that are tightly wound by DNA and are the basic unit of chromatin are called A. operons. B. nucleosomes. C. protein clusters. D. repressor genes. E. facilitators sites.

12. The hallmark of multicellular organisms is their ability to A. grow and divide rapidly. B. adjust quickly to outside environment. C. maintain homeostasis. D. quickly synthesize amount and type of enzymes according to available nutrients. E. respond by gene action to oxygen availability.

13. Enhancers are the binding sites for the A. promoters of DNA synthesis. B. suppressor factors. C. co-activation factors. D. mediator factors. E. specific transcription factors.

14. Within its core a nucleosome contains ____ histones. A. 2 B. 4 C. 6 D. 8 E. 64

15. The basic tool of genetic regulation is the ability of certain proteins to bind to specific A. regulatory RNA sequences. B. regulatory DNA sequences. C. repressor parts of the gene. D. promoter parts of the gene. E. enzymes of the cell.

16. In vertebrates, DNA methylation - the addition of a methyl group to DNA nucleotides - ensures that A. the gene functions without interruption. B. no errors will be made during transcription. C. the nucleosome will quickly form, which assists in mRNA formation. D. once that gene is transcribed, the mRNA is saved and used over and over again. E. once a gene is turned off, it will remain off.

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 A. transcriptional repression. B. transcriptional activation. C. translational repression. D. translational activation.

18. Although the specific mechanism of RNA interference has not been fully defined, it involves A. double stranded RNA interference with mRNA. B. double stranded RNA interference with DNA. C. double stranded DNA interference with mRNA. D. double stranded mRNA interference with DNA.

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. B. DNA prints. C. fingerprints. D. repressors. E. transcriptional domains.

20. Small RNAs can regulate gene expression. One type, called micro RNA (miRNA), acts by binding directly to A. mRNA to prevent translation. B. tRNA to prevent transcription. C. mRNA to prevent transcription. D. tRNA to prevent translation.

21. The lac operon regulatory system is important to bacteria primarily because lactose A. cannot be made by bacteria unless the genes are turned on. B. is the most common source of food; enzymes are needed all the time. C. is only rarely available; producing enzymes all the time is costly. D. is incorporated into the nucleic acid of the bacteria. E. switches the system off and on whether lactose is present or not.

22. In eukaryotes, specific transcription factors have two distinct domains: A. a DNA-binding domain and a RNA-binding domain. B. a DNA-binding domain and an activation domain. C. a DNA-binding domain and a repressor domain. D. a DNA-binding domain and an enhancer domain. E. a DNA-binding domain and an operator domain.

23. In order for transcription to be initiated A. DNA polymerase must have access to the DNA double helix and must also be capable of binding to the gene's promoter. B. RNA polymerase must have access to the DNA double helix and must also be capable of binding to the gene's promoter. C. DNA polymerase must have access to the RNA and must also be capable of binding to the gene's promoter. D. RNA ligase must have access to the DNA double helix and must also be capable of binding to the gene's promoter. E. RNA polymerase must have access to the DNA double helix and also must be capable of binding to the gene's operator.

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. B. the minor groove of the DNA and reading the nucleotide base pairs. C. the major groove of RNA and reading the nucleotide base pairs. D. DNA's major groove by using DNA polymerase and reading the nucleotide base pairs. E. DNA's minor groove by using DNA polymerase and reading the nucleotide base pairs.

25. Regulatory proteins can identify specific sequences on the DNA double helix without unwinding the helix. This is accomplished by inserting A. RNA promoters into either the major groove or the minor groove of the double helix where the edges of the nitrogen bases protrude. B. DNA-binding motifs into the minor groove of the double helix where the edges of the nitrogen bases protrude. C. DNA polymerase into the major groove of the double helix where the edges of the nitrogen bases protrude. D. RNA polymerase into the major groove of the double helix where the edges of the nitrogen bases protrude. E. DNA-binding motifs into the major groove of the double helix where the edges of the nitrogen bases protrude.

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 A. trp transcriptional operator. B. trp regulator. C. trp suppressor. D. trp operon. E. trp promoter.

27. The proteins necessary for the use of lactose in E. coli are collectively called the A. lac regulator. B. lac suppressor. C. lac operon. D. lac promoter. E. lac transcriptional operator.

28. A defining characteristic of eukaryotic organisms is that they A. have their transcription occurring in the cytoplasm and translation in the nucleus. B. have their transcription occurring in the nucleus and translation in the cytoplasm. C. have only operons to assist in gene expression. D. carry out protein synthesis only in the presence of the cAMP molecule. E. use the leucine zipper primarily for the production of the amino acid tryptophan.

29. The primary transcripts in eukaryotes are most accurately described as A. composed of RNA polymerase and associated histones. B. having the exons removed and the introns retained for translation. C. a faithful copy of the entire gene including exons and introns. D. an exact copy of the gene, but the introns have been removed. E. an RNA copy, but the non-coding exons and introns have been removed.

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 A. non-helical zipper. B. leucine zipper. C. zinc finger. D. homeodomain. E. helix-turn-helix.

31. The most common DNA-binding motif is the A. non-helical zipper. B. leucine zipper. C. zinc finger. D. homeodomain. E. helix-turn-helix.

32. A protein that regulates transcription by binding to the operator is known as the A. operon. B. repressor. C. promoter. D. operator. E. CAP.

33. A protein that initiates gene transcription and allows for non-glucose molecules to be used is A. operon. B. repressor. C. promoter. D. operator. E. CAP.

34. A cluster of functionally-related genes that are regulated together and encoded into a single mRNA molecule is called a(n) A. operon. B. repressor. C. promoter. D. operator. E. CAP.

35. A site of negative genetic regulation where binding by repressor blocks transcription is the A. operon. B. repressor. C. promoter. D. operator. E. CAP.

36. A site at the 5' end of a gene where RNA polymerase attaches to initiate transcription is called a(n). A. operon. B. repressor. C. promoter. D. operator. E. CAP.

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. B. repressor. C. effector. D. operon.

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. B. repressor. C. effector. D. operon.

39. The main form of glucose repression in the lac operon is A. induction. B. repression. C. inducer exclusion. D. the CAP/cAMP system.

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. B. prevention of the repressor from binding to the operator. C. depression of the trp operon. D. enabling of the trp operon to be expressed in the absence of tryptophan.

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 A. the operon is ON in the absence of its regulatory protein. B. the operon is OFF in the absence of its regulatory protein. C. the presence of an inducer will always cause a repressor to bind the operator. D. the presence of an inducer will always prevent a repressor from binding the operator.

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 A. TFIIA, TFIIB, TFIIE, TFIIF, TFIIH B. TFIIB-TFIIA, TFIIF, TFIIE, TFIIH, TFIIJ C. TFIIF-TFIIH, TFIIB, TFIIE, TFIIA, TFIIH D. TFIIE, TFIIB, TFIIA, TFIIH, TFIIF

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 A. abandon this experiment and try a vastly different approach to your question, since transcription domains cannot be separated. B. express large amounts of the general transcription factors. C. express and purify only the DNA-binding domain, since transcription domains can be separated. D. try to express and purify only the activation domain, since transcription domains can be separated.

44. You are working to identify enhancer regions of a particular gene. The best place to begin your search is A. immediately upstream of the promoter. B. immediately downstream of the promoter. C. primarily upstream of the promoter; distance from the promoter does not matter. D. primarily downstream of the promoter; distance from the promoter does not matter.

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. B. inducer. C. basal transcription factor. D. specific transcription factor.

46. The TFIID complex is formed by A. TATA-binding protein TBP and TAFs. B. TATA-binding protein TBP, TAFs and RNA pol II. C. TAFs and the core promoter. D. TATA-binding protein and activators.

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 A. DNA acetylation. B. chromatin remodeling. C. recruitment of RNA pol II. D. formation of the transcription initiation complex.

48. DNA methylation is the only known natural modification of DNA. It affects A. adenine bases. B. guanine bases. C. cytosine bases. D. thymine bases.

49. If you were able to look very closely at a portion of DNA and find methylated histones, you would A. be mistaken since only DNA can be methylated, not histones. B. be looking at a region of active chromatin. C. be looking at a region of inactive chromatin. D. be looking at a chromatin remodeling complex.

50. Elucidation of the histone code might A. allow us to turn specific genes on or off. B. allow the determination of nucleosome composition. C. lead to chromatin remodeling. D. allow us to control translation.

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 A. to design a repressor to bind to the operon of this gene. B. use a histone deacetylase to induce a transcriptionally inactive state. C. use a C. elegans strain with a homozygous TFIID mutation to prevent the translation initiation complex from forming. D. use RNA interference to prevent mRNA translation.

52. The enzyme dicer chops dsRNA molecules into small pieces of A. mRNA and miRNA. B. miRNA and siRNA. C. siRNA and rRNA. D. mRNA and siRNA.

53. The gene encoding apolipoprotein B exists in two isoforms, APOB100 and APOB48. These two forms are produced as a result of A. tissue-specific expression. B. a gene mutation that results in a stop codon. C. RNA editing. D. alternative splicing.

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 A. transcription repressor protein. B. translation repressor protein. C. RNA interference protein. D. translation initiation protein.

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. B. Genes that are derepressed are turned on because an inducer molecule is present. By comparison, a gene that is induced is turned on because a repressor molecule is absent. C. There is no functional difference between a gene that is derepressed and one that is induced. D. A derepressed gene is turned off and an induced gene is activated to be expressed.

56. A group of your students were doing analysis on the formation of polymerase II initiation complex, however they have mixed up there findings and you must now organize these findings to represent the true formation of the pathway. _ mRNAs produced _ TFIIB and TFIIA then bind to the complex _ TFIIF bound to RNA Pol-II then binds _ TFIID binds to TATA box _ TFIIE, TFIIH, and TFIIJ bind

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? A. Attachment of ubiquitin to the protein, which would lead to transport of the protein to the lysosome that would engulf the protein and degrade it with lysozymes. B. Tagging of the protein with ubiquitin and then proteolysis of the protein by proteases in the proteasomes. C. Tagging of the protein with oligosaccharides first, which would then lead into the transport of the protein to proteasomes for proteolysis via proteases. D. Oligonucleotides would attach to the protein and transport it to the lysosomes for digestion and recycling into products for energy formation.

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? A. The transcription factor transcribes small RNAs that then bind to the promoter and activate the gene's expression. B. Signals originate via inducers from the transcription factor to the site of promotion that activate transcription of the gene. C. DNA looping transports the transcription factor closer to the promoter and initiates gene transcription. D. The assistance of RNA looping moves the transcription factor closer to the promoter.

59. Control of gene expression ____ allows bacteria to adapt to changing environments. ____ is critical for development in multicellular organisms. _____ allows bacteria to replicate without control. ____ allows multicellular organisms to maintain homeostasis. _____ it stops multicellular organisms functioning as a whole.

60. Examples of shapes in regulatory proteins that are used to bind to DNA include ____ zinc finger. _____ TATA box. ____ helix-turn-helix. ____ leucine zipper. _____ Doubledomain.

61. A bacterial gene regulatory system is likely have ____ a coding sequence. ____ an operator. _____ one or more introns. _____ a motor. ____ a ribosome recognition site.

62. Control of the lac operon and lactose utilization in bacteria is ____ not induced in the presence of both glucose and lactose. _____ only induced when there is glucose but not lactose. ____ is a negative control, mediated by a repressor. ____ controlled by the expression of three downstream genes. _____ preferentially utilizing lactose as a carbon source.

63. The eukaryotic transcription initiation complex is ____ transcription of virtually all genes transcribed by RNA pol II requiring the same suite of general factors. ____ responsible for highly regulated transcription levels. _____ only associated with RNA polymerase I. ____ interactive with activators through DNA looping. _____ a basal factor associated with RNA pol II after positioning RNA pol II at the start site.

64. The ubiquitin-proteasome pathway ____ is used to regulate expression of a number of cell surface receptors. _____ requires only one molecule of ATP to target a protein. ____ targets proteins in a stepwise fashion via ubiquitin ligase adding ubiquitin residues to the protein. _____ is used to digest macromolecules. ____ does not destroy the ubiquitin moiety, but rather cleaves it off for reuse.