Portage Microbiology Exam 3 Questions and Answers
Already Passed
Define the concept of universal precautions (short answer) - 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) - 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) - 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) - 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 - 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 - ANSWER B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left
untreated - ANSWER Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of
human population where it remains non-symptomatic - ANSWER False.
Staphylococcus in only found (non-symptomatic) in ~30% of the human population
, Define commensal bacteria (short answer) (know term and definition first) -
ANSWER The bacterium neither harms nor benefits from the host from which it
obtains nutrients
How can staphylococcus be differentially tested? (short answer) - ANSWER
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - ANSWER Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - ANSWER Ruptured-pustules; treated with
penicilin
Symptoms of Impetigo - ANSWER Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - ANSWER Infections of thin, transparent scieral tissue
Symptoms of ophthalmia neonatorum - ANSWER Infection occurs at time of birth
True or False: the causative agent of conjunctivitis can be either bacterial or viral -
ANSWER True. There are bacterial (staph) and viral forms of conjunctivitis, both
resulting in the inflammation of the conjunctiva and 'pink eye'
True or False: Tuberculosis is best identified by a gram stain - ANSWER False.
Mycobacterium show poor Gram staining and show be screened via an acid-fast
stain
True or False: You can become infected with TB simply by sharing a drink with
someone who is currently infected with TB - ANSWER False. As per the CDC
guidelines, simply shaking someone's hand, sharing a drink, or even kissing
someone cannot spread TB
Identify the disease based on the following (select all that apply): It is a small, acid-
fast rod usually remaining asymptomatic for up to 20 years. It affects the skin,
nerves, upper respiratory tract and eyes of infected individuals
A. Tuberculosis
B. Leprosy
C. Scalded-skin syndrome
D. Hansen's disease
E. Bacterial conjunctivitis - ANSWER B & D (Hansen's disease is another name for
leprosy)
True or False: Only directly ingesting the pre-formed clostridium toxin (neither the
bacteria nor its spores) will cause disease in adults - ANSWER True
While visiting his grandparents, a 10-year old child has green beans for dinner that
were harvested from his grandparents' garden and canned the previous year. Severe
illness sets in and the child is taken to the hospital. Botulism is suspected, but what
form? (short answer) - ANSWER Foodbourne botulism. The child is too old (> 6
months) to be considered and wounds were not present. The green beans were
Already Passed
Define the concept of universal precautions (short answer) - 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) - 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) - 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) - 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 - 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 - ANSWER B. Carbohydrate composition of antigens
Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left
untreated - ANSWER Beta: strep. Pharyngitis
True or False: Under most circumstances, staphylococcus can be found in ~80% of
human population where it remains non-symptomatic - ANSWER False.
Staphylococcus in only found (non-symptomatic) in ~30% of the human population
, Define commensal bacteria (short answer) (know term and definition first) -
ANSWER The bacterium neither harms nor benefits from the host from which it
obtains nutrients
How can staphylococcus be differentially tested? (short answer) - ANSWER
Staphylococcus species are capable of growth in the presence of bile salts
Symptoms of folliculitis - ANSWER Pus-filled lesions on skin or hair
Symptoms of scalded-skin syndrome - ANSWER Ruptured-pustules; treated with
penicilin
Symptoms of Impetigo - ANSWER Childhood skin disease near mouth/nose
Symptoms of conjuctivitis - ANSWER Infections of thin, transparent scieral tissue
Symptoms of ophthalmia neonatorum - ANSWER Infection occurs at time of birth
True or False: the causative agent of conjunctivitis can be either bacterial or viral -
ANSWER True. There are bacterial (staph) and viral forms of conjunctivitis, both
resulting in the inflammation of the conjunctiva and 'pink eye'
True or False: Tuberculosis is best identified by a gram stain - ANSWER False.
Mycobacterium show poor Gram staining and show be screened via an acid-fast
stain
True or False: You can become infected with TB simply by sharing a drink with
someone who is currently infected with TB - ANSWER False. As per the CDC
guidelines, simply shaking someone's hand, sharing a drink, or even kissing
someone cannot spread TB
Identify the disease based on the following (select all that apply): It is a small, acid-
fast rod usually remaining asymptomatic for up to 20 years. It affects the skin,
nerves, upper respiratory tract and eyes of infected individuals
A. Tuberculosis
B. Leprosy
C. Scalded-skin syndrome
D. Hansen's disease
E. Bacterial conjunctivitis - ANSWER B & D (Hansen's disease is another name for
leprosy)
True or False: Only directly ingesting the pre-formed clostridium toxin (neither the
bacteria nor its spores) will cause disease in adults - ANSWER True
While visiting his grandparents, a 10-year old child has green beans for dinner that
were harvested from his grandparents' garden and canned the previous year. Severe
illness sets in and the child is taken to the hospital. Botulism is suspected, but what
form? (short answer) - ANSWER Foodbourne botulism. The child is too old (> 6
months) to be considered and wounds were not present. The green beans were
