Straighterline Microbiology Final Exam 2025
100+ Questions With Complete Answers
1.In a search for new antibiotics, a previously unknown organism has been
recovered from the soil. It is nonmotile and is composed of long threadlike
structures formed from nucleated cells. It is not-photosynthetic and absorbs its
nutrients. This organism will most likely be classified among the...
a. bacteria
b. archaea
c. eukaryotes (fungi)
d. eukaryotes (protozoa)
e. eukaryotes (algae) - ANSWER c. eukaryotes (fungi)
2. If immersion oil was replaced with water, what would happen?
a. The refractive index would increase, improving resolution
b. The refractive index of water would be greater than air but less than oil,
improving resolution less than oil.
c. The refractive index of water would be less than that of air, decreasing
resolution.
d. There would be no difference. - ANSWER b. The refractive index of water
would be greater than air but less than oil, improving resolution less than oil.
3. Prior to staining, smears of microorganisms are heat-fixed in order to...
a. allow eventual visualization of internal structures.
,b. ensure removal of dust particles from the slide surface.
c. attach it firmly to the slide.
d. create small pores in cells that facilitates binding of stain to cell structures. -
ANSWER c. attach it firmly to the slide.
4. If the decolorizer is left on too long in the Gram-staining procedure, gram-
positive organisms will be stained __________ and gram-negative organisms will
be stained __________.
a. purple; blue
b. purple; colorless
c. purple; pink
d. pink; pink - ANSWER d. pink; pink
5. Regions of a specimen with higher electron density scatter ___________
electrons and, therefore, appear __________ in the image projected onto the screen
of a transmission electron microscope.
a. more; lighter
b. more; darker
c. fewer; darker
d. fewer; lighter - ANSWER b. more; darker
6. In the Gram-staining procedure, the mordant is...
a. iodine.
b. safranin.
,c. crystal violet.
d. alcohol. - ANSWER a. iodine.
7. Acid-fast organisms such as Mycobacterium tuberculosis contain lipids
constructed from ________________in their cell walls.
a. proteins
b. carbohydrates
c. mycolic acids
d. peptidoglycan - ANSWER c. mycolic acids
8. Fatty acid methyl ester (FAME) analysis is particularly important in public
health because in this application, microbiologists seek to identify specific
microbial pathogens in ______.
a. food and water
b. patient samples
c. genomic analysis
d. genetic diseases - ANSWER a. food and water
9.Studies by Emil von Behring and Shibasaburo Kitasato demonstrated that
inactivated toxins can induce the synthesis of antitoxins in the blood of rabbits.
These antitoxins (antibodies) are the basis of...
a. humoral immunity
b. cell-mediated immunity
c. antibiotic immunity
d. phagocyte-mediated immunity - ANSWER a. humoral immunity
, 10. Who of the following first discovered that some blood leukocytes could engulf
disease-causing bacteria?
a. von Behring
b. Meister
c. Metchnikoff
d. Ivanowski - ANSWER c. Metchnikoff
11. Who is credited with developing a vaccine against chicken cholera?
a. Koch
b. Pasteur
c. Jenner
d. Lister - ANSWER b. Pasteur
12.The concept that living organisms arise from nonliving material is called...
a. biogenesis
b. cell theory
c. spontaneous generation
d. germ theory - ANSWER c. spontaneous generation
13. Protists contain all of the following forms of life EXCEPT...
a. protozoa
100+ Questions With Complete Answers
1.In a search for new antibiotics, a previously unknown organism has been
recovered from the soil. It is nonmotile and is composed of long threadlike
structures formed from nucleated cells. It is not-photosynthetic and absorbs its
nutrients. This organism will most likely be classified among the...
a. bacteria
b. archaea
c. eukaryotes (fungi)
d. eukaryotes (protozoa)
e. eukaryotes (algae) - ANSWER c. eukaryotes (fungi)
2. If immersion oil was replaced with water, what would happen?
a. The refractive index would increase, improving resolution
b. The refractive index of water would be greater than air but less than oil,
improving resolution less than oil.
c. The refractive index of water would be less than that of air, decreasing
resolution.
d. There would be no difference. - ANSWER b. The refractive index of water
would be greater than air but less than oil, improving resolution less than oil.
3. Prior to staining, smears of microorganisms are heat-fixed in order to...
a. allow eventual visualization of internal structures.
,b. ensure removal of dust particles from the slide surface.
c. attach it firmly to the slide.
d. create small pores in cells that facilitates binding of stain to cell structures. -
ANSWER c. attach it firmly to the slide.
4. If the decolorizer is left on too long in the Gram-staining procedure, gram-
positive organisms will be stained __________ and gram-negative organisms will
be stained __________.
a. purple; blue
b. purple; colorless
c. purple; pink
d. pink; pink - ANSWER d. pink; pink
5. Regions of a specimen with higher electron density scatter ___________
electrons and, therefore, appear __________ in the image projected onto the screen
of a transmission electron microscope.
a. more; lighter
b. more; darker
c. fewer; darker
d. fewer; lighter - ANSWER b. more; darker
6. In the Gram-staining procedure, the mordant is...
a. iodine.
b. safranin.
,c. crystal violet.
d. alcohol. - ANSWER a. iodine.
7. Acid-fast organisms such as Mycobacterium tuberculosis contain lipids
constructed from ________________in their cell walls.
a. proteins
b. carbohydrates
c. mycolic acids
d. peptidoglycan - ANSWER c. mycolic acids
8. Fatty acid methyl ester (FAME) analysis is particularly important in public
health because in this application, microbiologists seek to identify specific
microbial pathogens in ______.
a. food and water
b. patient samples
c. genomic analysis
d. genetic diseases - ANSWER a. food and water
9.Studies by Emil von Behring and Shibasaburo Kitasato demonstrated that
inactivated toxins can induce the synthesis of antitoxins in the blood of rabbits.
These antitoxins (antibodies) are the basis of...
a. humoral immunity
b. cell-mediated immunity
c. antibiotic immunity
d. phagocyte-mediated immunity - ANSWER a. humoral immunity
, 10. Who of the following first discovered that some blood leukocytes could engulf
disease-causing bacteria?
a. von Behring
b. Meister
c. Metchnikoff
d. Ivanowski - ANSWER c. Metchnikoff
11. Who is credited with developing a vaccine against chicken cholera?
a. Koch
b. Pasteur
c. Jenner
d. Lister - ANSWER b. Pasteur
12.The concept that living organisms arise from nonliving material is called...
a. biogenesis
b. cell theory
c. spontaneous generation
d. germ theory - ANSWER c. spontaneous generation
13. Protists contain all of the following forms of life EXCEPT...
a. protozoa
