Portage Microbiology Exam #5
1). Define the concept of universal precautions (short answer)
Ans: Universal precautions means any and all samples, whether known or unknown,
are to be treated as potentially hazardous (or pathogenic) materials
2). List at lease 3 observations a researcher would be sure to note while assessing and
unknown microbial sample (short answer)
Ans: Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
3). 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)
Ans: 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.
4). A facultative anaerobe is a microorganism capable of growth under what conditions? (short
answer)
Ans: A facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions
5). True or false: the lancefield groups are used to subdivide antigenic groups of alpha-
hemolytic streptococcus
Ans: False. The Lancefield groups are used to subdivide beta-hemolytic strep
6).
PaperStoc.com Page 1 of 8
, 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
Ans: B. Carbohydrate composition of antigens
7). Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left untreated
Ans: Beta: strep. Pharyngitis
8). True or false: under most circumstances, staphylococcus can be found in ~80% of human
population where it remains non-symptomatic
Ans: False. Staphylococcus in only found (non-symptomatic) in ~30% of the human
population
9). Define commensal bacteria (short answer) (know term and definition first)
Ans: The bacterium neither harms nor benefits from the host from which it obtains
nutrients
10). How can staphylococcus be differentially tested? (short answer)
Ans: Staphylococcus species are capable of growth in the presence of bile salts
11). Symptoms of folliculitis
Ans: Pus-filled lesions on skin or hair
12). Symptoms of scalded-skin syndrome
Ans: Ruptured-pustules; treated with penicilin
13). Symptoms of impetigo
Ans: Childhood skin disease near mouth/nose
14). Symptoms of conjuctivitis
PaperStoc.com Page 2 of 8
1). Define the concept of universal precautions (short answer)
Ans: Universal precautions means any and all samples, whether known or unknown,
are to be treated as potentially hazardous (or pathogenic) materials
2). List at lease 3 observations a researcher would be sure to note while assessing and
unknown microbial sample (short answer)
Ans: Need to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
3). 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)
Ans: 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.
4). A facultative anaerobe is a microorganism capable of growth under what conditions? (short
answer)
Ans: A facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions
5). True or false: the lancefield groups are used to subdivide antigenic groups of alpha-
hemolytic streptococcus
Ans: False. The Lancefield groups are used to subdivide beta-hemolytic strep
6).
PaperStoc.com Page 1 of 8
, 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
Ans: B. Carbohydrate composition of antigens
7). Rheumatic fever displays _____ hemolytic activity and occurs when _____ if left untreated
Ans: Beta: strep. Pharyngitis
8). True or false: under most circumstances, staphylococcus can be found in ~80% of human
population where it remains non-symptomatic
Ans: False. Staphylococcus in only found (non-symptomatic) in ~30% of the human
population
9). Define commensal bacteria (short answer) (know term and definition first)
Ans: The bacterium neither harms nor benefits from the host from which it obtains
nutrients
10). How can staphylococcus be differentially tested? (short answer)
Ans: Staphylococcus species are capable of growth in the presence of bile salts
11). Symptoms of folliculitis
Ans: Pus-filled lesions on skin or hair
12). Symptoms of scalded-skin syndrome
Ans: Ruptured-pustules; treated with penicilin
13). Symptoms of impetigo
Ans: Childhood skin disease near mouth/nose
14). Symptoms of conjuctivitis
PaperStoc.com Page 2 of 8
