Antarctic habitats have rich but poorly described microbial communities. You hav

Question

Antarctic habitats have rich but poorly described microbial communities. You have traveled to a particularly harsh, dry, and frigid region known as the Mars Oasis in the hopes of learning more about its resident bacteria. After a morning of exploring, you bring back a sample of soil to the laboratory. Microscopic examination of your sample reveals a large number of rods, cocci, and filamentous cells growing together in a tangled mass. You first decide to plate a portion of the sample on a nutrient medium in an attempt to grow isolated colonies. You then apply a dye mixture containing propidium iodide and Syto-9 to your sample and view it using fluorescence microscopy. The rods and cocci both appear green, while the filamentous cells are nearly all red. A few days later you observe your plates and notice that colonies of a uniform appearance have grown. When you observe these cells under the microscope, they are all cocci, similar in appearance to those from your original sample.

:A.   cocci / rods

B.   cocci / filamentous cells

C.   rods / cocci

D.   filamentous cells / cocci

E.   rods / filamentous cells

F.   filamentous cells / rods

Explanation / Answer

The most likely explanation for your results would be that the __________ were nonviable, to begin with, and the __________ have specific, but as yet unknown, nutritional requirements.

Correct option:

Explanation: The filamentous cells stained red on the application of the stain which the viable cells which are metabolically active stains green in color.

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