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Microbiology University Of Texas - Arlington -
Microbiology Lab UTA – Final Questions With
Complete Solutions
What is the difference between a substance that is
bacteriostatic and one that is bacteriocidal? -
....ANSWER ....✔✔ Bacteriostatic: stops bacterial
growth/reproduction
Bactericidal: kills bacterial cells
What is a zone of inhibition? How is it interpreted? -
....ANSWER ....✔✔ Area in which growth has not
occurred; diameter must be measured and compared to
accepted values
What is the difference between broad-spectrum and
narrow-spectrum antibiotics? - ....ANSWER ....✔✔
Broad-spectrum abx work on both gram pos and gram
negative, but not necessarily all
Narrow-spectrum abx work only on either gram-positive
or gram-negative bacteria, not both.
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Why is Mueller-Hinton agar used to test antibiotic
susceptibility? - ....ANSWER ....✔✔ It contains starch,
which neutralizes toxins produced by the bacteria
What is the difference between an antiseptic and a
disinfectant? - ....ANSWER ....✔✔ A disinfectant is
used to kill bacteria on inanimate objects while an
antiseptic is applied to tissue to kill bacteria.
How does antibacterial resistance arise in bacterial
populations? - ....ANSWER ....✔✔ Mutation; selective
pressure is applied by the antibiotic and natural
selection ensues, resulting in the mutation for resistance
to appear in future generations.
What are some consequences of antibacterial
resistance? - ....ANSWER ....✔✔ Infections which are
difficult (or even impossible) to treat, leaving patients
sicker for longer and more susceptible to complications
How is MSA selective? What does it select for? -
....ANSWER ....✔✔ High salt concentration; only
certain Gram positive cocci may grow on it
Microbiology University Of Texas - Arlington -
Microbiology Lab UTA – Final Questions With
Complete Solutions
What is the difference between a substance that is
bacteriostatic and one that is bacteriocidal? -
....ANSWER ....✔✔ Bacteriostatic: stops bacterial
growth/reproduction
Bactericidal: kills bacterial cells
What is a zone of inhibition? How is it interpreted? -
....ANSWER ....✔✔ Area in which growth has not
occurred; diameter must be measured and compared to
accepted values
What is the difference between broad-spectrum and
narrow-spectrum antibiotics? - ....ANSWER ....✔✔
Broad-spectrum abx work on both gram pos and gram
negative, but not necessarily all
Narrow-spectrum abx work only on either gram-positive
or gram-negative bacteria, not both.
, 2|Page
Why is Mueller-Hinton agar used to test antibiotic
susceptibility? - ....ANSWER ....✔✔ It contains starch,
which neutralizes toxins produced by the bacteria
What is the difference between an antiseptic and a
disinfectant? - ....ANSWER ....✔✔ A disinfectant is
used to kill bacteria on inanimate objects while an
antiseptic is applied to tissue to kill bacteria.
How does antibacterial resistance arise in bacterial
populations? - ....ANSWER ....✔✔ Mutation; selective
pressure is applied by the antibiotic and natural
selection ensues, resulting in the mutation for resistance
to appear in future generations.
What are some consequences of antibacterial
resistance? - ....ANSWER ....✔✔ Infections which are
difficult (or even impossible) to treat, leaving patients
sicker for longer and more susceptible to complications
How is MSA selective? What does it select for? -
....ANSWER ....✔✔ High salt concentration; only
certain Gram positive cocci may grow on it
