Block 4 Exam

BLOCK FOUR QUESTIONS

1. Helicases are A. enzymes B. motor proteins that separate DNA C. a form of RNA polymerase that synthesize primers D. a and b E. a and c 2. The sliding clamp’s function is to… A. synthesize new DNA in the 5’ to 3’ direction B. prevent DNA polymerase III from disassociating from the template C. break and form bonds to unknot or untwist DNA during replication D. separate and unwind DNA so that DNA polymerase can bind for replication E. all of the above 3. In DNA replication nucleotides are added to? A. the 5’ end via phosphodiester bond B. the 3’ end via phosphodiester bond C. the 5’ end via phosphoanhydride bond D. the 3’ end via phosphoanhydride bond 4. Which of the following e.Coli DNA polymerases has a proofreading function? A. pol I B. pol II C. pol III D. pol IV E. all of the above 5. The DNA repair mechanism that would most likely be utilized to fix damage from UV light would be? A. mismatch repair B. base excision repair C. nucleotide excision repair D. strand break repair E. damage bypass mechanism 6. Which of the following is INCORRECT regarding XPV mutations? A. patients suffer from sun sensitivity and early cancer onset B. inherited via an autosomal recessive fashion C. defect in translesion polymerase function D. DNA polymerase can’t accurately replicate past thymine dimers E. can no longer perform nucleotide excision repair 7. Which of the following types of RNA is the carrier of amino acids for protein synthesis during translation? A. rRNA B. tRNA C. mRNA D. snRNA E. hnRNA 8. Which statement is incorrect regarding transcription? A. catalyzd by DNA dependent RNA polymerase B. synthesized in the 5’ to 3’ direction C. no proofreading mechanism exists D. RNA primer is required E. synthesis is initiated at promoter elements 9. Which best describes the function of enhancers in transcription? A. recruits DNA binding proteins and determines strength of promoter B. determines the transcription site C. determines the direction of synthesis D. determines whether a chromosome locus is active E. directs RNA polymerase to the site of initiation 10. The newly synthesixed RNA of one gene before RNA processing occurs is known as? A. tRNA B. primary transcript C. intron D. catalytic RNA E. ribonucleoprotein 11. Which of the following amino acid sequences is not a common STOP codon? A. UAA B. UAG C. UGA D. AUG E. all are stop codons 12. In mRNA translation, the element(s) upstream from the start codon is/are? A. the coding sequence B. the stop codon C. the poly-A tail D. the 5’ cap E. all of the above are upstream of the start codon 13. Which coding sequence mutation results in a different amino acid being used, such as in Sickle Cell Anemia? A. silent B. missense C. nonsense D. insertion E. deletion 14. Translation occurs in the? A. mitochondria B. cytosol C. rough ER D. smooth ER lumen E. golgi bodies 15. The regulation of translation initiation in red blood cell development, occuring in response to cell stress, amino acid depletion, or unfolded protein accumulation, occurs via what mechanism? A. a decrease in free tRNA as a result of AA depletion B. phosphorylation of eIF2 elongation factor by HIR kinase C. failure to hydrolyze GTP and lock aa-tRNA into the A site D. inhibition of the large subunit to transfer polypeptide due to lack of free phosphate E. cell stress would result in the overproduction of RBC via enhanced globin synthesis

16. Transcription factors bind to all of the following except? A. enhancers B. steroid hormones C. basal transcription complex (RNA Polymerase) D. ribozymes E. co-activators 17. Which statement is incorrect regarding transcriptional co-activators? A. they bind DNA B. interact with activators directly C. can bridge to RNA Polymerase-2 D. can be basal factors E. can be enzymes 18. The methylation of histones and DNA usually results in? A. stabilization of electrostatic forces B. expression of the methylated gene C. disassociation of histone deacetylase complexes D. gross denaturing of surrounding chromatin E. differential expression of an allele 19. Which statement is FALSE regarding DNA microarray?

A. DNA probes are laid out in a precise grid B. DNA and RNA can be hybridized to the probes C. this clinical correlate in disguise is is a waste of our time D. pattern of association is measured by antibody staining 20. Following the reading of a stop codon, what is the order of translational termination? A. aminoacyl bond is cleaved, tRNA released, ribosome subunits disassociate B. aminoacyl bond is cleaved, ribosome subunits disassociate, tRNA released C. ribosome subunits disassociate, tRNA released, aminoacyl bond is cleaved D. tRNA released, aminoacyl bond is cleaved, ribosome subunits disassociate E. ribosome subunits disassociate, aminoacyl bond is cleaved, tRNA released 21. Which of the following antibiotics blocks peptide formation and A to P translocation? A. tetracyclins B. erythromycin C. aminoglycosides D. chloramphenicol

22. Which is NOT a part of the core promoter region? A. TATA box B. initiator sequence C. enhancer D. downstream promoter element E. none of the above 23. Proteins tagged with C terminal tripeptides are targeted to? A. nucleus B. mitochondria C. peroxisome D. lysosome E. ER 24. Protein synthesis occurs in all of the following except? A. cytosol B. ER C. nucleus D. mitochondrial ribosomes For 25-30 Match the process on the left with it’s respective cellular location on the right. 25. protein folding                                                                 A.  nucleus 26. chaperone binding                                                            B.  cytosol 27. transport from ER to cis golgi                                          C.  ER lumen 28. transcription                                                                      D.  transport vesicle 29. transport from trans golgi to cell membrane                     E. secretory vesicle 30. translation                                                                         F. lysosome G. endosome

31. Proteins tagged with an N terminus alpha helix are targeted to? A. nucleus B. mitochondria C. peroxisome D. lysosome E. ER 32. Proteins tagged with C terminal tripeptides are targeted to? A. nucleus B. mitochondria C. peroxisome D. lysosome E. ER 33. Which structure is responsible for the membrane bound portion of an ER transmembrane protein becoming embedded? A. chaperones B. stop transfer sequences C. heat shock protein 40 D. heat shock protein 60 E. heat shock protein 70 34. Proteins tagged with N terminal signal peptides are targeted to? A. nucleus B. mitochondria C. peroxisome D. lysosome E. ER 35. Covalent modification of proteins in the ER lumen is facilitated by? A. heat shock proteins b. protein disulfide isomerase C. asparagine D. Ire1 E. BiP 36. Proteins tagged with mannose-6-P are targeted to? A. nucleus B. mitochondria C. peroxisome D. lysosome E. ER 37. Silencer regions are located (in the)? A. initiator sequence B. transcribed sequence C. thousands of nucleotides upstream from the transcribed sequence D. thousands of nucleotides downstream of the transcribed sequence E. B, C, and D

BLOCK FOUR ANSWERS 1. D 2.  B 3.  B 4.  C 5.  C 6.  E 7.  B 8.  D 9.  A 10. B 11. D 12. D 13. B 14. B 15. B 16. D 17. A 18. E 19. D (arguably c) 20. A 21. B 22. C 23. C 24. C 25. C 26. B 27. D 28. A 29. E 30. B 31. B 32. C 33. B 34. E 35. B 36. D 37. E