ACTUAL Exam Questions and CORRECT
Answers
Define the concept of universal precautions. - CORRECT ANSWER - Universal
precautions means any and all samples, whether known or unknown, are to be treated as
potentially hazardous (or pathogenic) materials.
List at least 3 observations a researcher would be sure to note while assessing an unknown
microbial sample. - CORRECT ANSWER - 1. size and shape
2. gram status
3. any observable motility
While observing an unknown sample of limited amounts, a researcher must determine the
following observations: (1) the presence of any motility and (2) its Gram status using the same
sample—the liquid sample cannot be divided. Which would you determine first and why? -
CORRECT ANSWER - You would need to determine the motility first and then the Gram
status. Motility requires a wet mount and Gram staining requires heat fixing the sample. If you
perform a Gram stain first the heat fixation would kill the organism, making it impossible to
observe motility.
A facultative anaerobe is a microorganism capable of growth under what conditions? -
CORRECT ANSWER - It is capable of growth under both anaerobic and aerobic
conditions
As Streptococcus is catalase negative would it thrive or die in the presence of peroxides? Why? -
CORRECT ANSWER - It would die. Because it is catalase negative it wouldn't be able to
breakdown peroxides.
Streptococcus is most often streaked onto:
- Chocolate agar
- EMB agar
, - Blood agar
- Spirit Blue agar - CORRECT ANSWER - Blood agar
Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in
the classification (and differentiation) process.
True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-
hemolytic Streptococcus. - CORRECT ANSWER - False
The Lancefield groupings are used to subdivide beta-hemolytic Strep
Greater than 90% of all human streptococcal infections belong to:
- Group C
- Group B
- Group A
- Group D - CORRECT ANSWER - Group A
Group A is the causative agent behind> 90% of all strep infections
Rheumatic fever displays ______ hemolytic activity and occurs when _______ is left untreated.
Beta; Rheumatic fever
Alpha; Strep. Pharyngitis
Beta; Strep. Pharyngitis
Gamma; Strep. Septicemia - CORRECT ANSWER - Beta; Strep. Pharyngitis
Strep throat (also known as strep. Pharyngitis) can lead to Rheumatic fever if left untreated and
displays beta-hemolytic activity