Exam 1: UAMS Microbiology (Latest 2026/2027 Update) Questions with Verified Answers | 100% Correct| Graded A.

Exam 1: UAMS Microbiology (Latest
2026/2027 Update) Questions with Verified
Answers | 100% Correct| Graded A.
Question:

What are the different morphologies of bacteria??
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Answer:

Coccus, coccobacillus, vibrio, bacillus, spirillum, and spirochete.
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Question:

What are the different bacterial arrangements for cocci??
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Answer:
Coccus (one single colony), diplococci (two colonies), staphylococci
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(multiple colonies in a triangle shape), streptococci (multiple colonies in a
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linear row), sarcina (multiple colonies that can be on top of one another in
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a square shape), and tetrad (four colonies in a square).
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Question:

What does bacillus or bacilli refer to? What about Bacillus? What are the
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bacilli arrangements??
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Answer:

,Rod shaped. The genus (Bacillus anthracis). Single bacillus, diplobacilli,
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streptobacilli, and palisade (rods laid side by side, forming a fence-like
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appearance; can also be V-shaped). i,- i,- i,- i,-




Question:

What does the term pleomorphic refer to? Ex. Pleomorphic bacilli?
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Answer:

Bacteria that is capable of altering its morphology to take on many
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different shapes. i,-




Question:

What are spores and what do they allow a bacterium, such as bacilli with
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spores??
Answer:
Spores are cells with very thick walls that can survive many extremes,
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allowing a bacterium protection in order to preserve its genetic material.
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Question:
What are the two different forms of bacilli rods??
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Answer:

Filamentous and fusiform. i,- i,-

,Question:

Who invented the Gram stain and staining method? What are the
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reagents involved? How is Gram stain able to work? What makes some
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bacteria gram pos and others neg??
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Answer:

Hans Christian Gram. Crystal violet, iodine, decolorizer, and safranin. The
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cell wall structure of the bacteria is what determines if it is gram pos or
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neg. The thick peptidoglycan layer on gram pos MOs retains the crystal
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violet-iodine complex. On gram neg MOs, there is only a thin layer of
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peptidoglycan under a layer of lipids. The lipid layer retains the stain and
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the decolorizer then dissolves the lipid layer, removing the crystal violet-
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iodine complex. i,-




Question:
What is the counter stain that is used alongside Gram stain to identify the
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Gram neg bacteria? How does this work??
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Answer:

Safranin. Once the decolorizer dissolves the lipid layer holding the crystal
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violet-iodine complex, the safranin is able to stain the thin peptidoglycan
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layer underneath, causing the bacteria to appear pink. The pink bacteria
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can then be identified as Gram neg.
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, Question:
What is smear? What is important when preparing a smear? How are
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smears heat fixed and why?? i,- i,- i,- i,-




Answer:

Cells from a culture are taken and spread over a thin area of a slide and
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then heat fixed. The smear doesn't need to be too thin or too thick,
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otherwise it will be unable to be read properly. Smears are heat fixed
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using a bunsen burner, an electric incinerator, or methanol. This is done to
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kill the bacteria on the slide, prevent bacteria from washing off the slide,
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and allowing the smear to take up stain better.
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Question:
What is the Gram staining procedure??
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Answer:
Place the slide on a staining rack and cover the smear with crystal violet
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solution. Let stand for 30-60 seconds. Rinse with tap water to remove the
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crystal violet, then shake off excess water. Cover the smear with Gram's
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iodine and let stand for 30-60 seconds. Rinse with water, then shale off
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excess. Decolorize the smear with acetone-alcohol and rinse with water as
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soon as the purple/blue color no longer runs off the slide. *Be careful to
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not over or under decolorize* Shake off excess water and counterstain
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with safranin for 30 seconds, rinse with water, and dry slide by air or by
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blotting.




Question: