Portage Microbiology Exam #5 questions and
answers 2024\2025 A+ Grade
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
answers 2024\2025 A+ Grade
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
