Microbiology Straighterline
Exam With 100%
Correct And Verified Answers 2025/26
1. 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 - Correct Answer> -a. humoral
immunity
2. Who of the following first discovered that some blood leukocytes could
engulf disease-causing bacteria?
a. von Behring
b. Meister
c. Metchnikoff
d. Ivanowski - Correct Answer> -c. Metchnikoff
3. Who is credited with developing a vaccine against chicken cholera?
a. Koch
b. Pasteur
c. Jenner
d. Lister - Correct Answer> -b. Pasteur
4. The concept that living organisms arise from nonliving material is
called...
a. biogenesis
b. cell theory
c. spontaneous generation
d. germ theory - Correct Answer> -c. spontaneous generation
5. Protists contain all of the following forms of life EXCEPT...
a. protozoa
b. fungi
c. slime molds
d. algae - Correct Answer> -b. fungi
[Type here]
,Microbiology Straighterline exam with
100% correct and verified answers 2024
6. Cells with a relatively simple cell morphology that do not have a true
membrane-delimited nucleus are called...
a. prokaryotes
b. eukaryotes
c. urkaryotes
d. nokaryotes - Correct Answer> -a. prokaryotes
7. The ribosomal RNA studies that led to the division of prokaryotic
organisms into the Bacteria and the Archaea were begun by...
a. Pasteur
b. Woese
c. Needham
d. Watson - Correct Answer> -b. Woese
8. 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) - Correct Answer> -c. eukaryotes (fungi)
9. 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. - Correct Answer> -b. The refractive
index of water would be greater than air but less than oil,
improving resolution less than oil.
10. Prior to staining, smears of microorganisms are heat-fixed in order
to...
a. allow eventual visualization of internal structures.
,Microbiology Straighterline exam with
100% correct and verified answers 2024
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. - Correct Answer> -c. attach it firmly to the slide.
11. 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 - Correct Answer> -d. pink; pink
12. 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 - Correct Answer> -b. more; darker
13. In the Gram-staining procedure, the mordant is...
a. iodine.
b. safranin.
c. crystal violet.
d. alcohol. - Correct Answer> -a. iodine.
14. Acid-fast organisms such as Mycobacterium tuberculosis contain
lipids constructed from ________________in their cell walls.
a. proteins
b. carbohydrates
c. mycolic acids
d. peptidoglycan - Correct Answer> -c. mycolic acids
15. 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
, Microbiology Straighterline exam with
100% correct and verified answers 2024
b. patient samples
c. genomic analysis
d. genetic diseases - Correct Answer> -a. food and water
16. Genomic DNA sequences seem to support the idea that the first
eukaryotic cell arose from within the _____ lineage.
a. archaeal
b. bacterial
c. viral
d. last universal common ancestor (LUCA) - Correct Answer> -a.
archaeal
17. An unrooted tree containing four unrelated species can become
rooted by adding
a. a descendant group related to two of the species.
b. an unrelated outgroup.
c. a distantly related outgroup.
d. a descendant related to only one of the species. - Correct Answer>
-c. a distantly related outgroup.
18. A general term used to describe groups based on mutual similarity
or evolutionary relatedness is ______.
a. class
b. taxa
c. system
d. group - Correct Answer> -b. taxa
19. The temperature at which half of the strands of a double-stranded
DNA molecule have separated from each other is called the __________
temperature.
a. separation
b. melting
c. destabilizing
d. mobilization - Correct Answer> -b. melting
20. Which of the following is true about Bergey's Manual?
a. The first edition is mostly phenetic while the second edition is more
phylogenetic.
Exam With 100%
Correct And Verified Answers 2025/26
1. 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 - Correct Answer> -a. humoral
immunity
2. Who of the following first discovered that some blood leukocytes could
engulf disease-causing bacteria?
a. von Behring
b. Meister
c. Metchnikoff
d. Ivanowski - Correct Answer> -c. Metchnikoff
3. Who is credited with developing a vaccine against chicken cholera?
a. Koch
b. Pasteur
c. Jenner
d. Lister - Correct Answer> -b. Pasteur
4. The concept that living organisms arise from nonliving material is
called...
a. biogenesis
b. cell theory
c. spontaneous generation
d. germ theory - Correct Answer> -c. spontaneous generation
5. Protists contain all of the following forms of life EXCEPT...
a. protozoa
b. fungi
c. slime molds
d. algae - Correct Answer> -b. fungi
[Type here]
,Microbiology Straighterline exam with
100% correct and verified answers 2024
6. Cells with a relatively simple cell morphology that do not have a true
membrane-delimited nucleus are called...
a. prokaryotes
b. eukaryotes
c. urkaryotes
d. nokaryotes - Correct Answer> -a. prokaryotes
7. The ribosomal RNA studies that led to the division of prokaryotic
organisms into the Bacteria and the Archaea were begun by...
a. Pasteur
b. Woese
c. Needham
d. Watson - Correct Answer> -b. Woese
8. 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) - Correct Answer> -c. eukaryotes (fungi)
9. 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. - Correct Answer> -b. The refractive
index of water would be greater than air but less than oil,
improving resolution less than oil.
10. Prior to staining, smears of microorganisms are heat-fixed in order
to...
a. allow eventual visualization of internal structures.
,Microbiology Straighterline exam with
100% correct and verified answers 2024
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. - Correct Answer> -c. attach it firmly to the slide.
11. 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 - Correct Answer> -d. pink; pink
12. 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 - Correct Answer> -b. more; darker
13. In the Gram-staining procedure, the mordant is...
a. iodine.
b. safranin.
c. crystal violet.
d. alcohol. - Correct Answer> -a. iodine.
14. Acid-fast organisms such as Mycobacterium tuberculosis contain
lipids constructed from ________________in their cell walls.
a. proteins
b. carbohydrates
c. mycolic acids
d. peptidoglycan - Correct Answer> -c. mycolic acids
15. 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
, Microbiology Straighterline exam with
100% correct and verified answers 2024
b. patient samples
c. genomic analysis
d. genetic diseases - Correct Answer> -a. food and water
16. Genomic DNA sequences seem to support the idea that the first
eukaryotic cell arose from within the _____ lineage.
a. archaeal
b. bacterial
c. viral
d. last universal common ancestor (LUCA) - Correct Answer> -a.
archaeal
17. An unrooted tree containing four unrelated species can become
rooted by adding
a. a descendant group related to two of the species.
b. an unrelated outgroup.
c. a distantly related outgroup.
d. a descendant related to only one of the species. - Correct Answer>
-c. a distantly related outgroup.
18. A general term used to describe groups based on mutual similarity
or evolutionary relatedness is ______.
a. class
b. taxa
c. system
d. group - Correct Answer> -b. taxa
19. The temperature at which half of the strands of a double-stranded
DNA molecule have separated from each other is called the __________
temperature.
a. separation
b. melting
c. destabilizing
d. mobilization - Correct Answer> -b. melting
20. Which of the following is true about Bergey's Manual?
a. The first edition is mostly phenetic while the second edition is more
phylogenetic.
