On Gram stain, mycobacteria appear as:

a. slender, well-stained gram-positive bacilli.
b. poorly stained, beaded, gram-positive ba-cilli.
c. gram-variable to gram-positive bacilli.
d. partially invisible gram-negative bacilli.


B
Because of their cell wall makeup, mycobacteria usually appear as slender, poorly stained, beaded, gram-positive bacilli on Gram stain. Sometimes they appear as "gram-neutral" or "gram-ghosts" by failing to take up either crystal violet or safranin.

Biology & Microbiology

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What will be an ideal response?

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Protein folding can be studied using a solution of purified protein and a denaturant (urea), a solvent that interferes with noncovalent interactions. Which of the following is observed after the denaturant is removed from the protein solution?

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Biology & Microbiology