1. Treatment of chromatin with micrococcal nuclease results in the formation of a. nucleosomes. b. chromatosomes. c. core particles. d. All of these choices are true. 2. Nucleosomes consist of a. DNA. b. histones. c. DNA and histones. d. nonhistone proteins and DNA. 3. The apparent function of a nucleosome is to a. supercoil eukaryotic chromosomes. b. provide the first order of chromatin folding. c. cause decondensation of chromatin during metaphase. d. participate in the final looping and condensing of chromosomal DNA. 4. The second order of chromosome condensation a. involves formation of a solenoid. b. appears as a string of nucleosomes. c. occurs only under low salt conditions. d. All of these choices are true. 5. Which histone is thought to participate in solenoid formation? a. H1 b. H2A c. H2B d. H4 6. Eukaryotic RNA polymerases I, II, and III were so named in reference to a. the importance of their activities. b. the size of each enzyme. c. the types of RNA they make. d. the order of elution from an ion exchange column. 7. A down mutation in a gene that encodes RNA polymerase II would a. result in a decrease in ribosomal RNA levels. b. be a lethal mutation. c. result in a decrease in 5S rRNA levels. d. not affect a cell to any appreciable extent. 8. A TATA box can be found a. 25 bases upstream of a eukaryotic promoter. b. 10 bases upstream of a eukaryotic promoter. c. 75 bases upstream of a eukaryotic promoter. d. 35 bases upstream of a prokaryotic promoter. --- 9. A fragment of DNA containing an RNA polymerase II promoter was heavily mutated in the -25 region, and then added to an in vivo transcription system. The most likely observation would be that a. transcription was completely eliminated. b. the number of transcription start sites decreased. c. the number of transcription start sites increased. d. there was no change in the level of transcription. 10. Eukaryotic RNA polymerase I promoters a. flank the rRNA precursor gene on the 3'-side. b. closely resemble RNA polymerase II promoters. c. function in transcription of RNA precursor genes. d. have the TATA and CCAAT upstream sequences. 11. A deletion of the -50 to -5 region of a gene under the control of an RNA polymerase III promoter would result in a. complete elimination of transcription of tRNA and 5S rRNA genes. b. continued, but less efficient, transcription of tRNA and 5S rRNA genes. c. formation of a truncated transcript of tRNA genes. d. no change in the level of transcription. 12. Enhancer sequences a. are always found immediately upstream of a promoter. b. enhance transcription even when located far away from a promoter. c. encode enhancer-binding proteins that bind to and stimulate transcription at susceptible promoters. d. are highly conserved in nature. 13. Which of the following is not a transcription factor? a. T protein from SV40 virus b. Sp1 protein from HeLa cells c. TFIIIA protein from Xenopus laevis d. HAP from Drosophila melanogaster 14. Eukaryotes control gene expression at the level of a. transcription. b. post-transcription. c. translation. d. All of the above are true. 15. Which eukaryotic mRNA does not have a poly(A) tail? a. histone mRNA b. B-globin mRNA c. conalbumin mRNA d. ribosomal protein mRNA --- 16. In an R-looping experiment, single-stranded DNA from a gene of interest was hybridized to an mRNA transcript of the gene. Several R-loops formed. This indicates that a. the gene contains one intron. b. there are no introns in this gene. c. the gene has one exon. d. the gene contains several introns. 17. Exons represent sequences of DNA that are a. never transcribed. b. cut out of mature RNAs. c. part of a gene's coding region. d. found in heterochromatin. 18. Introns are found in a. mRNA. b. DNA. c. prokaryotes and eukaryotes. d. all tRNA genes. 19. An intron is a. a region of mRNA that is not translated. b. an integral part of a ribosome. c. an inverted repeat in a gene's 5'-flanking region. d. a region of DNA that is not represented by amino acids in a gene's product. 20. Heterogeneous nuclear RNAs are a class of large nuclear RNAs that a. are precursors of mRNA. b. contain introns. c. result from transcription of a gene with introns. d. All of these choices are true. 21. Introns are characterized by which of the following consensus sequences? a. GU-intron-AG b. CG-intron-CG c. GU-intron-UA d. GU-intron-UG 22. A deletion mutation within an intron found in a beta-globin gene would result in a. beta-thalassemia. b. a decrease in functional beta-globin mRNA. c. no translation of the beta-globin gene transcript. d. no change in transcription or translation of the gene. 23. When intron consensus sequences are mutated, a. abnormal splicing of genomic mRNA occurs. b. transcription of the intron's genes can't be initiated. c. nothing happens, because introns are removed from mRNA. d. transcripts containing introns cannot be spliced. --- 24. A spliceosome consists of a. mRNA precursor and snRNP's. b. snRNP and an antibody against snRNP. c. an intron DNA sequence and snRNP. d. U1 snRNP and mRNA. 25. In eukaryotes, ribosomal RNAs are a. encoded in several different genes that are transcribed and then spliced. b. encoded in an operon and transcribed into polycistronic mRNA. c. encoded in a single gene that is transcribed and then cut into smaller pieces. d. encoded in a single gene with no introns. 26. The signal for polyadenylation in higher eukaryotes includes the consensus sequence a. TATAAT. b. AATAAA. c. AAUAAA. d. UAAUAA. 27. The messenger RNAs of which of the following organisms do not contain introns? a. Xenopus laevis b. E. coli c. Drosophila melanogaster d. human 28. Scientific evidence supports the view that posttranscriptional regulation of gene expression in eukaryotes occurs by a. differential capping. b. polyadenylation of selected mRNAs. c. transportation of selected mRNAs to the cytoplasm. d. selective degradation of mRNAs in the cytoplasm. 29. Posttranslational regulation of gene expression in eukaryotes involves a. proteolytic cleavage of proteins. b. methylation of specific phosphate groups in proteins. c. capping of the N-terminal amino acid of the protein. d. All of these choices are true. 30. An important signature of eukaryotic mRNAs is a(n) a. poly(T) tail on their 5'-ends. b. poly(A) tail on their 3'-ends. c. 200 nucleotide inverted repeat sequence on their 5'-ends. d. AAUAA sequence at their 3'-ends. 31. Histones from different organisms show a large degree of genetic divergence. 32. Eukaryotic chromosomes are linear and therefore are not supercoiled. 33. Histones are the only proteins known to be associated with chromatin. --- 34. Eukaryotic organisms have three different RNA polymerases. 35. Sigma factors in eukaryotes show a large degree of homology with their prokaryotic counterparts. 36. Eukaryotic RNA polymerase I promoter sequences closely resemble promoter sequences for RNA polymerase II and III. 37. RNA polymerase III promoters are situated within the genes they control. 38. The 72 base-pair repeat upstream sequence found in the SV40 tumor virus is actually a promoter. 39. Eukaryotic genes show colinearity between genes and gene products. 40. Transfer RNAs have been found to contain only one intron or none at all. 41. DNA, when complexed with protein and coiled up in an organized manner, is called __________. 42. Eukaryotic promoters that bind __________ recognize both a TATA box and a second upstream sequence. 43. Elements that are important to transcription but are not an actual part of a promoter are __________. 44. Eukaryotic genes sometimes contain __________, which are subject to posttranscriptional processing. 45. The mechanism of mRNA precursor splicing involves a __________-shaped intermediate. 46. What is the evidence to indicate that histones are important in eukaryotic genetic systems? 47. Briefly describe the lariat model of RNA precursor splicing. 48. List three ways in which eukaryotic mRNAs differ from prokaryotic mRNAs. 49. What are the functions of the three distinct RNA polymerases found in eukaryotes? 50. What is the function of the long poly(A) tail found on most eukaryotic mRNAs? --- 51. This is thymidine: The portion circled is a(n) a. purine b. pyrimidine c. amino acid d. sugar Circle the 5' and 3' ends of this molecule. It base pairs with a. uracil b. adenine c. cytosine d. quanine The entire structure shown is a a. nitrogenous base b. nucleoside c. nucleotide d. trinucleotide 52. Which of the following statements about Cot analysis of DNA is false? a. Cot analysis measures the rate at which single-stranded DNA reassociates b. DNA with a 1/2 Cot value of 400 would be 10 times larger than one with a value of 40. c. If there is repetitive DNA in an organisms genome, this DNA will have a lower 1/2 Cot value than the rest of the DNA. d. Cot means concentration/time. 53. The most direct technique for examining the size of DNA is: a. Cot analysis b. electron microscopy c. gel electrophoresis d. autoradiography 54. A site on the DNA that binds RNA polymerase tightly is a: a. promoter b. operator c. repressor d. sigma factor 55. Proper initiation of transcription requires all except: a. repressor b. core RNA polymerase c. sigma factor d. DNA with a promoter region --- 56. A protein that is required for termination of some transcription is: a. CI b. cro c. sigma d. rho 57. Inverted repeats might be found in all cases except: a. as part of an operator b. as part of an attenuator c. as part of a transcriptional terminator d. as part of a translational terminator 58. For the following, fill in the blanks with the proper term from the list below: promoter repressor aporepressor CAP protein operator inducer corepressor cAMP When a growing E. coli encounters lactose, the lactose (actually allolactose) acts as a(n) ________________ of the lac operon. It acts by binding to the lac ______________, causing it to dissociate from the lac ________________. This allows transcription of the lac operon, provided that the ______________ is bound near the lac promoter. Tryptophan acts as a(n) __________________of the trp operon by binding to the ___________________, which allows it to bind tightly to the trp _______________. 59. The genes for the trp operon: a. code for the enzymes for tryptophan biosynthesis b. code for the enzymes for utilizing tryptophan as a carbon and nitrogen source c. allow lactose to be used as a carbon source d. are repressed when tryptophan is absent 60. What are the properties that make DNA ideally suited as the genetic material? 61. Describe or draw what occurs in rolling circle replication. What types of organisms do this? --- 62. Because of wobble, the anticodon 3'CUG5' can pair with: a. 5'GAC3' and 5'GAT3' b. 5'GAC3' and 5'GAU3' c. 5'GAC3' and 5'CAC3' d. only 5'GAC3' 63. What is gene conversion, and how does homologous recombination explain how it might occur? 64. Draw what is meant by bidirectional replication, and show how a pulse-labelling experiment demonstrates bidirectional replication. 65. Repressors binding to operators are involved in all except: a. catabolite repression by glucose and the CAP protein. b. enzyme induction by lactose. c. enzyme repression by tryptophan. d. the action of gene CI in producing lysogeny in phage lambda. 66. On a strand of mRNA, translation starts: a. at the first base. b. at the first AUG codon. c. at the first UAG codon. d. at the first thymidine nucleotide. 67. Nucleosomes, loops, and solenoids are involved in: a. transcription b. folding of DNA c. translation of mRNA d. splicing of primary RNA transcripts 68. Two genes that have a high frequency of co-transduction: a. are far apart from each other. b. would also have a high frequency of recombination. c. would be near each other on the chromosome. d. would be the same gene. 69. The major means by which antibiotic resistance genes are transferred to new strains is by: a. conjugation of plasmids carrying resistance genes. b. Hfr-mediated transfer of resistance genes found on the chromosome of a resistant strain. c. transduction. d. transformation. --- 70. Match the description on the left with the term on the right. _____synthesis of DNA a. promoter _____synthesis of RNA b. transcription _____snythesis of protein c. translation _____RNA polymerase binding site d. replication _____Repressor binding site e. repressor _____Hairpin loop and poly-U's f. translation terminator g. transcription terminator 71. In the process of splicing, draw the missing intermediate: exon 1 intron exon 2 exon 1 exon 2