PORTAGE MICROBIOLOGY EXAM 5 QUESTIONS
WITH CORRECT ANSWERS 2025/2026
Define the concept of universal precautions (short answer) - 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 lease 3 observations a researcher would be sure to note while assessing and unknown
microbial sample (short answer) - CORRECT ANSWER -Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
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? (short
answer) - CORRECT ANSWER -You must determine motility before determining Gram status.
Motility requires a wet mount, while gram staining requires heat fixing the sample. If one were
to begin with the gram stain, the heat fixation process would kill the organism, making any
observations regarding motility impossible. The correct approach would be to place the liquid
culture on a glass slide and determine its motility status. Next, the same liquid culture can be
heat fixed and gram stained.
A facultative anaerobe is a microorganism capable of growth under what conditions? (short
answer) - CORRECT ANSWER -A facultative anaerobe is capable of growth under aerobic (with
oxygen) and anaerobic (without oxygen) conditions
True or False: The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic
Streptococcus - CORRECT ANSWER -False. The Lancefield groups are used to subdivide beta-
hemolytic strep
, The distinctions for Lancefield subgroups lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above - CORRECT ANSWER -B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left untreated -
CORRECT ANSWER -Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of human
population where it remains non-symptomatic - CORRECT ANSWER -False. Staphylococcus in
only found (non-symptomatic) in ~30% of the human population
Define commensal bacteria (short answer) (know term and definition first) - CORRECT ANSWER
-The bacterium neither harms nor benefits from the host from which it obtains nutrients
How can staphylococcus be differentially tested? (short answer) - CORRECT ANSWER -
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - CORRECT ANSWER -Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - CORRECT ANSWER -Ruptured-pustules; treated with
penicilin
Symptoms of Impetigo - CORRECT ANSWER -Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - CORRECT ANSWER -Infections of thin, transparent scieral tissue
WITH CORRECT ANSWERS 2025/2026
Define the concept of universal precautions (short answer) - 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 lease 3 observations a researcher would be sure to note while assessing and unknown
microbial sample (short answer) - CORRECT ANSWER -Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
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? (short
answer) - CORRECT ANSWER -You must determine motility before determining Gram status.
Motility requires a wet mount, while gram staining requires heat fixing the sample. If one were
to begin with the gram stain, the heat fixation process would kill the organism, making any
observations regarding motility impossible. The correct approach would be to place the liquid
culture on a glass slide and determine its motility status. Next, the same liquid culture can be
heat fixed and gram stained.
A facultative anaerobe is a microorganism capable of growth under what conditions? (short
answer) - CORRECT ANSWER -A facultative anaerobe is capable of growth under aerobic (with
oxygen) and anaerobic (without oxygen) conditions
True or False: The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic
Streptococcus - CORRECT ANSWER -False. The Lancefield groups are used to subdivide beta-
hemolytic strep
, The distinctions for Lancefield subgroups lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above - CORRECT ANSWER -B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left untreated -
CORRECT ANSWER -Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of human
population where it remains non-symptomatic - CORRECT ANSWER -False. Staphylococcus in
only found (non-symptomatic) in ~30% of the human population
Define commensal bacteria (short answer) (know term and definition first) - CORRECT ANSWER
-The bacterium neither harms nor benefits from the host from which it obtains nutrients
How can staphylococcus be differentially tested? (short answer) - CORRECT ANSWER -
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - CORRECT ANSWER -Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - CORRECT ANSWER -Ruptured-pustules; treated with
penicilin
Symptoms of Impetigo - CORRECT ANSWER -Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - CORRECT ANSWER -Infections of thin, transparent scieral tissue
