Portage Microbiology BIOD171 Exam 5
GRADED A 2025
A facultative anaerobe is a microorganism capable of growth under what conditions? -
✔✔✔✔✔ A facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions.
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ✔✔✔✔✔ Streptococcus is catalse negative which means it cannot
break down peroxides and if any peroxides are present it would die.
Streptococcus is most often streaked onto: - ✔✔✔✔✔ 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. - ✔✔✔✔✔ False
The Lancefield groupings are used to subdivide beta-hemolytic Strep.
The distinctions for Lancefield subgroupings lie in its: (select all that apply)
Catalase activity
Hemolytic activity
Carbohydrate composition of antigens
All of the above - ✔✔✔✔✔ Carbohydrate composition of antigens
, Carbohydrate composition of antigens present in the cell wall determines the Lancefield
groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by definition)
catalase negative and beta-hemolytic. Thus, answers A and C cannot be used to
subdivide streptococcal species.
Left untreated, strep throat can progress to ______ , which displays _____ hemolytic
activity. - ✔✔✔✔✔ Rheumatic fever; beta
True or False. Under most circumstances, staphylococcus can be found in ~30% of
human population where it remains pathogenic. - ✔✔✔✔✔ false; While
staphylococcus can be found in ~30% of the human population, it remains non-
symptomatic.
When a bacterium neither harms nor benefits from the host from which it obtains
nutrients, it is referred to as being ___________. - ✔✔✔✔✔ Commensal
Attachment - ✔✔✔✔✔ pathogen finds a specific target tissue and adhere
evasion - ✔✔✔✔✔ pathogen masks its own antigens to hide from the host's immune
system
entry - ✔✔✔✔✔ utilization of a portal to gain access to host's tissues
Match the following diseases with their respective symptoms:
1. folliculitis
2. scalded-skin syndrome
3. impetigo
4. conjunctivitis
5. ophthalmia neonatorum
A. Childhood skin disease near mouth/nose
B. Infection of thin, transparent scleral tissue
C. Infection occurs at time of birth
D. Pus-filled lesions on skin or hair
E. Ruptured pustules; treated with penicillin - ✔✔✔✔✔ 1. D
GRADED A 2025
A facultative anaerobe is a microorganism capable of growth under what conditions? -
✔✔✔✔✔ A facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions.
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ✔✔✔✔✔ Streptococcus is catalse negative which means it cannot
break down peroxides and if any peroxides are present it would die.
Streptococcus is most often streaked onto: - ✔✔✔✔✔ 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. - ✔✔✔✔✔ False
The Lancefield groupings are used to subdivide beta-hemolytic Strep.
The distinctions for Lancefield subgroupings lie in its: (select all that apply)
Catalase activity
Hemolytic activity
Carbohydrate composition of antigens
All of the above - ✔✔✔✔✔ Carbohydrate composition of antigens
, Carbohydrate composition of antigens present in the cell wall determines the Lancefield
groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by definition)
catalase negative and beta-hemolytic. Thus, answers A and C cannot be used to
subdivide streptococcal species.
Left untreated, strep throat can progress to ______ , which displays _____ hemolytic
activity. - ✔✔✔✔✔ Rheumatic fever; beta
True or False. Under most circumstances, staphylococcus can be found in ~30% of
human population where it remains pathogenic. - ✔✔✔✔✔ false; While
staphylococcus can be found in ~30% of the human population, it remains non-
symptomatic.
When a bacterium neither harms nor benefits from the host from which it obtains
nutrients, it is referred to as being ___________. - ✔✔✔✔✔ Commensal
Attachment - ✔✔✔✔✔ pathogen finds a specific target tissue and adhere
evasion - ✔✔✔✔✔ pathogen masks its own antigens to hide from the host's immune
system
entry - ✔✔✔✔✔ utilization of a portal to gain access to host's tissues
Match the following diseases with their respective symptoms:
1. folliculitis
2. scalded-skin syndrome
3. impetigo
4. conjunctivitis
5. ophthalmia neonatorum
A. Childhood skin disease near mouth/nose
B. Infection of thin, transparent scleral tissue
C. Infection occurs at time of birth
D. Pus-filled lesions on skin or hair
E. Ruptured pustules; treated with penicillin - ✔✔✔✔✔ 1. D
