4. After performing a Gram stain on a Gram negative bacteria,the specimen shows purple bacteria. Which of the following bestexplains why this occurred? A. Crystal violet was not used B.Decolorizer was not used C. The specimen was not heat-fixed D.Safranin was not used

5. Which of the following pieces of evidence could support theendosymbiotic theory if found in some eukaryotes? A. Presence of80S ribosomes B. The presence of formylated methionine C. Genesthat allow for multiple origins of replication D. Gene forexpressing reverse transcriptase

6. A animal cell placed into a isotonic environment will: A. Notchange noticeably B. Lyse C. Shrivel D. Will “puff up” and swellbut not lyse

7. Which of the following correctly demonstrates the streakingmethod to obtain single colonies? Answer: 5. A researcher wishes todecrease the reactivity of an enzyme. Which of the following canshe do? A. Increase temperature B. Add an allosteric activator C.Add an allosteric inhibitor D. Add a competitive activator

8. What kind of oxygen requirement does the culture in thefigure MOST likely have? A. Microaerophile B. Facultative anaerobeC. Obligate aerobe D. Obligate anaerobe 7.

10. Which of the following could NOT explain why a streakedplate did not yield single colonies? A. The inoculation loop wasflamed before streaking B. The plate was contaminated C. After thefirst quadrant was inoculated, all following quadrants werestreaked from the first quadrant D. The inoculation loop was notflamed after the initial inoculation

11. You have recently identified a new toxin. It is produced bya gram-negative bacterium. It is has a lipid portion, and heatstable. Based on these characteristics, how would you classify thistoxin? A. superantigen B. endotoxin C. exotoxin D. A-B toxin