EXAM 3 practice test

1. Which statement about RNA polymerase is false?
a.RNA polymerase is an enzyme

b.Rna polymerase synthesizes new mRNA in the 3' to 5' direction adding new nucleotides to the 5' end of the growing polynucleotide chain

c.RNA polymerase has helicase activity

d.RNA polymerase adds either an A, U, C, or G ribonucleotide to a growing RNA strand based on the complementary base that is present on DNA
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1. Which statement about RNA polymerase is false?
a.RNA polymerase is an enzyme

b.Rna polymerase synthesizes new mRNA in the 3' to 5' direction adding new nucleotides to the 5' end of the growing polynucleotide chain

c.RNA polymerase has helicase activity

d.RNA polymerase adds either an A, U, C, or G ribonucleotide to a growing RNA strand based on the complementary base that is present on DNA
b.Rna polymerase synthesizes new mRNA in the 3' to 5' direction adding new nucleotides to the 5' end of the growing polynucleotide chain
2. You hypothesize that the virus X binding to cells initiates a specific cell signal transduction pathway for which you know some of the key protein kinases involved. How could you directly test the hypothesis that virus binding activates these kinases?

a. Infect cells and examine DNA replication kinetics

b. Infect cells and measure ion channel activity
Infect cells and compare DNA replication in infected cells versus non-infected cells

c. Compare the amount of phosphorylated protein kinases in infected cells versus non-infected cells

d. Measure the activity of the lac operon in infected cells versus non-infected cells.
d. Measure the activity of the lac operon in infected cells versus non-infected cells.
3. Starting with the following stretch of tRNAs, write down the mRNA that is recognized by the tRNAs tRNA= 3' AAG UUU GGG AUA 5'
a. 3' AAG TTT GGG ATA 5'

b. 3' TTC AAA CCC TAT 5'

c. 5' TTC AAA CCC TAT 3'

d.5' UUC AAA CCC UAU 3'

e. 3' UUC AAA CCC AUA 5'
d.5' UUC AAA CCC UAU 3'
4. Starting with the following stretch of tRNAs, write down the DNA template sequence tRNA= 3' AAG UUU GGG AUA 5'

a.5' UUC AAA CCC UAU 3'

b. 3' UUC AAA CCC UAU 5'

c.5' AAG UUU GGG AUA 3'

d.3' AAG TTT GGG ATA 5'

e.5' AAG TTT GGG ATA 3'
d.3' AAG TTT GGG ATA 5'
5. What would be a likely consequence of a G protein having GDP permanently attached to it?
a.The G protein would be activated when the ligand binds the G protein coupled receptor.

b.The G protein would remain in an "off" position and would be unable to relay the signal initiated by the ligand-receptor interaction

c.The G protein would operate normally

d.The G protein would be turned "on" all the time and be able to relay a signal even in the absence of ligand binding to the G protein coupled receptor

e.The G protein would be turned "on" all the time and be able to relay a signal as long as the ligand was bound to the G protein coupled receptor
b.The G protein would remain in an "off" position and would be unable to relay the signal initiated by the ligand-receptor interaction
6. Myc is a(n)____________ that mediates normal cell division induced by growth factors. When mutations occur resulting in a dysfunctional gene that leads to increased cell division then the mutated gene is called a(n)____________.
a. Spliceosome, trasnsgene.

b. Trasnsgene, proto-oncogene

c. Proto-oncogene, trasnsgene

d.Oncogene, proto-oncogene

e.Proto-oncogene, oncogene
e.Proto-oncogene, oncogene
7. What is meant when we say that the codon chart is unambiguous but redundant?
a. A single codon can code for multiple amino acids

b.A single codon can code for only one amino acid but multiple different codons can code for the same amino acid

c.Codons contain one to 3 amino acids

d.Genomes are different from one human cell to the next

e.Human genomes are similar in one human cell versus another but the genes that are expressed in each may differ
b.A single codon can code for only one amino acid but multiple different codons can code for the same amino acid
8.________ showed that _________is the transforming component that changed the non-pathogenic R bacteria into pathogenic S bacteria

a.Griffith, protein

b.Griffith, DNA

c.Avery, McCarty, Macleod, protein

d.Chargaff, DNA
c.Avery, McCarty, Macleod, protein
9. When responding to DNA damage, the p53 tumor suppressor protein functions as a __________and binds to the ________ of DNA repair enzyme genes to ______their expression

a.Translation factor, start codon, induce

b.Translation factor, start codon, reduce

c.Transcription factor, primer, induce

d.Transcription factor, primer, reduce

e.Transcription factor, promoter, induce
e.Transcription factor, promoter, induce
10. How do DNA nucleotides differ from RNA nucelotides?

a.The R groups are different

b.DNA contains uracil instead of Adenine

c.DNA nucleotides have a hexose sugar while RNA nucleotides have a pentose sugar

d.DNA has thymine instead of uracil

e.DNA contains, A,U, C, G and RNA contains A, T, C, G
d.DNA has thymine instead of uracil
11. If a sample of a rabbit DNA contains 15% thymine this means that a.A sample of human DNA would have 30% guanine b.A simple of human DNA would have 15% adenine c.A sample of the same rabbit DNA would have 15% cytosine d.A sample of the same rabbit DNA would have 35% guanine e.The RNA from the rabbit sample would contain 30% adenined.A sample of the same rabbit DNA would have 35% guanine12. Hershey and Chase used radiolabeled phages to determine whether the genetic material is protein or DNA. what would be the outcome of the experiment if the blender they used malfunctioned and was unable to shear off the phages from the bacteria prior to centrifugation a. the result would be the same b. only phage protein would be found in the cell pellet c. only phage DNA would be found in the cell pellet d. phage protein and DNA would be found in the cell pellet e. phage protein and DNA would be found in the supernatantd. phage protein and DNA would be found in the cell pellet13. when tryptophan levels are high tryptophan serves as the _______ which binds to the ____________ to ___________ transcription. a. activator, tryptophan genes, stimulate b. activator, operator, stimulate c. repressor, operator, inhibit d. co-repressor, operator, inhibit e. repressor, tryptophan genes, inhibitd. co-repressor, operator, inhibit14. why does the DNA double helix have a uniform diameter? a. purines pair with pyrimidines through covalent bonds b. purines pair with pyrimidines through hydrogen bonds c. purines pair with purines through covalent bonds d. purines pair with purines through hydrogen bonds e. pyrimidines pair with pyrimidines through hydrogen bondsb. purines pair with pyrimidines through hydrogen bonds15. lagging strand DNA synthesis requires multiple____________ a. tRNAs b. RNA polymerases c. ribosomes d. promoters e. RNA primerse. RNA primers16. what is the complementary DNA strand to 5' ATT CGG TGA 3' a. 5' AUU CGG TGU 3' B. 3' AUU CGG TGU 5' C. 5' TAA GCC ACT 3' D. 3' TAA GCC ACT 5' E. 3' ATT CGG TGA 5'D. 3' TAA GCC ACT 5'17. the main function of DNA polymerase is to a. synthesize DNA b. seal okazaki fragments together c. unwind DNA d. transcribe DNA e. synthesize proteinsa. synthesize DNA18. G protein coupled receptors______________ a. are located in the nucleus of a cell b. are transcription factors that bind directly to DNA c. are transcription factors that bind directly to RNA d. are located on the plasma membrane of a cell e. keep DNA strands apart during DNA replicationd. are located on the plasma membrane of a cell19. a ____________ is to transcription as a _____________ is to translation a. primer, promoter b. start codon, primer c. start codon, promoter d. promoter, start codon e. promoter, primerd. promoter, start codon20. You find that the lac repressor contains a mutation that enables it to bind automatically and _____ irreversibly to the operator upstream of the lac operon. How would lactose metabolism be affected when lactose levels rise in the cell. A. The lactose would be metabolized more quickly B. no effect would be observed C. high levels of tryptophan would block lactose metabolism D. the lactose would be metabolized more slowly. E. The lactose would not be metabolizedE. The lactose would not be metabolized21. what effect would a nonsense mutation have on protein synthesis? a. no effect b. a longer protein than expected would be generated c. a protein would be the same length as the wild type but would contain multiple different amino acids in the primary sequence d. a shorter protein than expected would be generated e. a protein would be the same length as the wild type but would contain a single different amino acid in the primary sequenced. a shorter protein than expected would be generated22. the pyrimidines are ___________ structures and include ______________ and _________________ a. single ring, thymine, cytosine b. single ring, adenine, guanine c. single ring, thymine, guanine d. double ring, adenine, guanine e. double ring, adenine, thyminea. single ring, thymine, cytosine23. A biochemist isolates and purifies molecules needed for DNA replication. When she adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A. DNA ligase B. primase C. Okazaki fragments D. DNA polymerase E. nucleotidesA. DNA ligase24. A ________ bond holds the amino acids of a growing polypeptide chain together during the elongation stage of translation. A. hydrogen B. peptide C. glycosidic D. non-covalent E. ionicB. peptide25. When _______________ levels are _____ the lac repressor is ________________ to the operator _____ and _______________ is ________________ A. lactose, low, not bound, lactose, anabolized B. tryptophan, low, bound, lactose, catabolized C. lactose, high, bound, lactose, catabolized D. lactose, high, not bound, lactose, catabolized E. tryptophan, high, bound, lactose, anabolizedD. lactose, high, not bound, lactose, catabolized26. What would be the consequence of a mutation that renders the large ribosomal subunit non-functional? a. DNA replication would be inhibited b. transcription would be inhibited c. cell signaling would be blocked d. helicase activity would be inhibitied e. translation would be inhibitede. translation would be inhibited27. Protein _________________ shut down a signal transduction pathway by _________________ proteins. A. kinases, phosphorylating B. kinases, dephosphorylating C. phosphatases, phosphorylating D. phosphatases, dephosphorylating E. kinases, degradingD. phosphatases, dephosphorylating28. A tRNA is charged by the addition of _______________________ A. a mRNA B. a ribosome C. a transcription factor D. a primer E. an amino acidE. an amino acid29. what is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? a. the origins of replication occur only at the 5' end b. helicases and single-strand binding proteins work at the 5' end c. DNA polymerase can join new nucleotides only to the 3' end of a growing strand d. DNA polymerase can join new nucleotides only to the 5' end of a growing strand e. polymerase can work on only one strand at a timec. DNA polymerase can join new nucleotides only to the 3' end of a growing strand30. when evaluating the nature of chromatin, a gene will most likely NOT be expressed when chromatin is in this form a. relaxed b. helixed c. heterochromatin d. euchromatin e. chromatin does not influence gene expressionc. heterochromatin31. __________________________ recruit the ____________________________ to ________________ _____ A. primase, primers, polypeptide B. transcription factors, RNA, ribosomes C. transcription factors, DNA, ribosomes D. transcription factors, RNA polymerase, promoters E. transcription factors, DNA polymerase, promotersD. transcription factors, RNA polymerase, promoters32. Assume each of the following letters represents an amino acid. What type of gene mutation occurred to produce the following protein sequence? Normal: JAYBIRDCATPAW Mutated:JAYBIRDBATPAW A) nonsense B) missense C) silent D) sense E) frameshiftB) missense33. The term C-terminus refers to the presence of a(n) ________ at one of the ends of a polypeptide. A) collagen B) carboxyl group C) creatine D) carbonyl group E) connexinB) carboxyl group34. From the perspective of the cell receiving the message, the three stages of cell signaling are: _____ A. the alpha, beta, and gamma stages. B. signal reception, nucleus disintegration, and new cell generation. C. signal reception, signal transduction, and cellular response. D. the paracrine, local, and synaptic stages. E. none of the aboveC. signal reception, signal transduction, and cellular response.35. Which of the following help(s) to stabilize mRNA by inhibiting its degradation? a. RNA polymerase b. TATA box c. introns d. spliceosomes e. 5' cap and poly A taile. 5' cap and poly A tail36. which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction? a. helicase b. DNA ligase c. DNA polymerase d. topoisomerase e. primasec. DNA polymerase37. If an mRNA sequence is 5′AUG-GGC-ACU-CAU3′, what would the anticodon sequence be? A. 3′AUG-GGC-ACU-CAU5′ B. 3′UAC-CCG-UGA-GUA5′ C. 5′AUG-GGC-ACU-CAU3′ D. 5′UAC-CCG-UGA-GUA3′ E. 3′TAC-CCG-TGA-GTA3′B. 3′UAC-CCG-UGA-GUA5′38. How many nucleotides are contained in a single codon? _____ A. 1 B. 3 C. 4 D. 6 E. 9B. 339. The process that produces mRNA from DNA is called A. transcription. B. translation. C. replication. D. processing. E. post-translational modification.A. transcription.40. ________ is to transcription as ________ are to translation? A. RNA splicesome; ribosomes B. RNA polymerase; ribosomes C. RNA polymerase; RNA splicesomes D. DNA polymerase; RNA polymerase E. DNA polymerase; ribosomesB. RNA polymerase; ribosomes41. The x-ray pictures of DNA taken by this scientist enabled Watson and Crick to build the correct model of DNA. A. Griffith B. Chargaff C. Franklin D. Morgan E. AveryC. Franklin42. A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be A. 5' TTG-CTA-CAG-TAG 3' B. 3' AAC-GAC-GUC-AUA 5' C. 3' AAA-AAT-ATA-ACA 5' D. 3' AAA-GAA-TAA-CAA 5' E. 5' AUG-CTG-CAG-TAT 3'D. 3' AAA-GAA-TAA-CAA 5'43. One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, then activating relay proteins. Which type does this? A. ligand-gated ion channels B. receptor tyrosine kinases C. steroid receptors D. G protein-linked receptor E. testosterone receptorB. receptor tyrosine kinases44. As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs? A. The tRNA that was in the A site moves into the P site. B. The polypeptide enters the E site. C. The tRNA that was in the A site departs from the ribosome via a tunnel. D. The tRNA that was in the P site moves into the A site. E. The tRNA that was in the A site moves to the E site and is released.A. The tRNA that was in the A site moves into the P site.45. All of the following are critical factors for DNA replication on the leading strand EXCEPT? a. primer b. ligase c. polymerase d. primase e. nucleotidesb. ligase46. A small molecule that specifically binds to a receptor to initiate a signal transduction pathway A. is called a phosphatase B. is called an enhancer C. is called a terminator D. seldom is involved in hormonal signaling. E. is called a ligand.E. is called a ligand.47. After mixing a heat-killed, fluorescent strain of bacteria with a living non-fluorescent strain, you discover that some of the living cells are now fluorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait? A. DNA passed from the heat-killed strain to the living strain. B. Protein passed from the heat-killed strain to the living strain. C. Both DNA and protein passed from the heat-killed strain to the living strain. D. The fluorescence in the living strain is especially bright. E. Descendants of the living cells are also fluorescent.E. Descendants of the living cells are also fluorescent.48. The general name for an enzyme that transfers phosphate groups from ATP to a protein is A. phosphatase. B. protein kinase. C. protease. D. ATPase. E. ubiquitinase.B. protein kinase.49) You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent A) leading strands and Okazaki fragments. B) lagging strands and Okazaki fragments. C) Okazaki fragments and RNA primers. D) leading strands and RNA primers. E) RNA primers and mitochondrial DNA.D) leading strands and RNA primers.50. The three steps of both transcription and translation are? a. DNA replication, ligation, fusion b. synthesis, dissemination, replacement c. initiation, elongation, termination d. translocation, replication, condensation e. reception, transduction, responsec. initiation, elongation, termination