Antarctic habitats have rich but poorly described microbial communities. You hav
ID: 147600 • Letter: A
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.