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There are 3 nutrient broth tubes. clostridium sporogenes was placedin one tube.

ID: 5442 • Letter: T

Question

There are 3 nutrient broth tubes. clostridium sporogenes was placedin one tube. staphylococcus epidermis was placed in another. bothbacteria were placed in equal proportions in the 3rd tube(100ul ofclostridium and 100ul of staph). The tubes were placed in anincubator.

What result should you see on Thursday that will demonstratecommensalism occurred?
a. All three cultures inoculated will be equally turbid.
b. Gram stain from the tube with both bacteria inoculated will showGram-positive staphylococci.
c. The tube with both bacteria inoculated will be the most turbidand show Gram-positive staphylococci and bacilli.
d. The tube with Clostridium only will be most turbid.
e. An endospore stain from the tube with both bacteria inoculatedwill show endospores

Explanation / Answer

Commensalism would show that both organisms benifited fromeach other. C shows that there was the most growth (by being mostturbid) in the tube, and that the tube contained bothorganisms.