205 Exam 2
2 PCR= Denature Dna
Add primer, Extend primer @ high temp 40. The Ames test strains are Histidine _____________ A. auxotrophs B. prototrophs
33. cell-free DNA ___________ 34 In the figure above
the enzyme in step 1 is A) DNA polymerase. B) DNA ligase. C) RNA polymerase. D) reverse transcriptase. E) spliceosome. 35. In the figure above, the enzyme in step 2 is A) DNA polymerase. B) DNA ligase. C) RNA polymerase. D) reverse transcriptase. E) spliceosome. Answer: D 36. If you have inserted a gene in the Ti plasmid, the next step in genetic engineering is A) transformation of E. coli with Ti plasmid. B) splicing T DNA into a plasmid. C) transformation of an animal cell. D) inserting the Ti plasmid into Agrobacterium. E) inserting the Ti plasmid into a plant cell. Naked viruses that don't have an envelope can not be killed rapidly by alcohol 37. In the figure above, the bacteria transformed with the recombinant plasmid and plated on media containing ampicillin and X-gal will A) form blue, ampicillin-resistant colonies. B) form blue, ampicillin-sensitive colonies. C) form white, ampicillin-resistant colonies. D) form white, ampicillin-sensitive colonies. E) not grow. Insert= white colonies Beta... - x-Gal = blue 38. Which of the following processes is NOT involved in making cDNA? A) reverse transcription B) RNA processing to remove introns C) transcription D) translation 39. Which of the following places the steps in the PCR procedure in the correct order? 1) Incubate at 94°C to denature DNA strands
9. An alkaline solution (CIDEX) is bactericidal
sporicidal, and viricidal even in the presence of organic matter.__________________
3) Incubate at 60°C for primer hybridization. A) 1
2, 3 B) 3, 2, 1 C) 1, 3, 2 D) 2
Figure 8 A suspension of 106 Bacillus cereus endospores was put in a hot-air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. Time to reduce population by one log = D value 8. In Figure 8 the decimal reduction time (D value) for the culture is approximately
A) 0 minutes. B) 10 minutes. C) 30 minutes. D) 40 minutes. E) 60 minutes.
15. Which of the following pairs is mismatched?
A) DNA polymerase — makes a molecule of DNA from a DNA template B) RNA polymerase — makes a molecule of RNA from an RNA template C) DNA ligase — joins segments of DNA (so wrong) D) transposase — insertion of DNA segments into DNA E) DNA gyrase — coils and twists DNA(could be but its not)
5. Which of the following is a limitation of the autoclave?
A) It requires an excessively long time to achieve sterilization. B) It cannot inactivate viruses. C) It cannot kill endospores. D) It cannot be used with heat-labile materials. E) It cannot be used with glassware.
23. An enzyme that copies DNA to make a molecule of RNA is
A) RNA polymerase. B) DNA ligase. C) DNA helicase. D) transposase. E) DNA polymerase. Transduction example....
16. Which of the following is NOT a product of transcription?
A) a new strand of DNA B) rRNA C) tRNA D) mRNA E) None of the answers are correct
2. Which of the following chemical agents is used for sterilization?
A) alcohol B) phenolics C) ethylene oxiede (gaseous stearlant) D) chlorine E) soap
6. All of the following substances are effective against nonenveloped viruses EXCEPT
A) alcohol. B) chlorine. C) ethylene oxide. D) ozone. E) None of the answers is correct
21. Synthesis of a repressible enzyme is stopped by the
A) allosteric transition. B) substrate binding to the repressor. C) corepressor binding to the operator. D) corepressor-repressor complex binding to the operator. (end product binds to corepresors) E) end product binding to the promoter.
7. Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
A) autoclave B) gamma radiation (penetrates any vagina) C) microwaves D) sunlight E) ultraviolet radiation
1. Which of the following is the best method to "sterilize" heat-labile solutions?
A) dry heat B) autoclave C) membrane filtration D) pasteurization E) freezing
4. Which of the following does NOT achieve sterilization?
A) dry heat B) pasteurization C) autoclave D) supercritical fluids E) ethylene oxide
19. An enzyme produced in response to the presence of a substrate is called a(n) (enzyme that acts on a substrate = catabolic)
A) inducible enzyme. B) repressible enzyme. C) restriction enzyme. D) operator. E) promoter.
20. Genetic change in bacteria can be brought about by
A) mutation. B) conjugation. C) transduction. D) transformation. E) All of the answers are correct.
22. Conjugation differs from reproduction because conjugation
A) replicates DNA. B) transfers DNA vertically, to new cells. C) transfers DNA horizontally, to cells in the same generation. D) transcribes DNA to RNA. E) copies RNA to make DNA.
3. The antimicrobial activity of chlorine is due to which of the following?
A) the formation of hypochlorous acid B) the formation of hydrochloric acid C) the formation of ozone D) the formation of a hypochlorite ion E) disruption of the plasma membrane
9.-14. Key words (used only once)
A. sodium lauryl sulfate B. autoclaving C. zephiran chloride(benzyalkonium chloride) D. ethylene oxide E.glutaraldehyde F. hexachlorophene G. membrane filtration H. phenol
25.-33. Make the best match. A letter may be used more than once.
A. transformation (natural or artificial) B. transduction C. Conjugation D. Transposition
2 will become F+
leu+, his+ E) 1 will remain the same
2 will become F+
leu-, his- C) 1 will become F-, leu-, his-
2 will become F+
leucine-, histidine- B) 1 will become F-, leu+, his+
18. In Table 18 (above)
what will be the result of conjugation between cultures 1 and 2? ,A) 1 will remain the same
17. In Figure 17 (above)
which colonies are streptomycin-resistant and leucine-requiring? ,A) 1, 2, 3, and 9 B) 3 and 9 C) 4, 6, and 8 D) 4 and 8 E) 5 and 6 Table 18 Culture 1: F+, leucine+, histidine+ Culture 2: F-, leucine-, histidine-
24. In the figure above
which model of the lac operon correctly shows RNA polymerase, lactose, and repressor protein when the structural genes are being transcribed? ,A) a B) b C) c D) d E) e
