2025 Microbiology Exam 1, with
Questions, Answers and Rationale
What is the correct sequence for a Gram stain?
Safranin, Crystal Violet, Gram's iodine, Alcohol
Crystal Violet, Safranin, Alcohol, Gram's iodine
Alcohol, Crystal Violet, Safranin, Gram's iodine
Crystal Violet, Gram's iodine, Alcohol, Safranin
Gram's Iodine, Crystal Violet, Alcohol, Safranin ------- Correct Ans ---------- Crystal Violet,
Gram's iodine, Alcohol, Safranin
Peptidoglycan is a unique macromolecule found in bacterial
cell membranes
capsules
slime layers
cell walls
inclusions ------- Correct Ans ---------- cell walls
Lysozyme, an enzyme found in tears, provides a natural defense against bacteria by
removing flagella.
removing the capsule from outside the cell.
hydrolyzing peptidoglycan in cell walls.
dissolving the cell membrane.
inhibiting protein synthesis. ------- Correct Ans ---------- hydrolyzing the peptidoglycan in cell
walls
,Bacteria with small bunches of flagella emerging from the same site are said to be
peritrichous.
amphitrichous.
lophotrichous.
monotrichous.
spirilla. ------- Correct Ans ---------- lophotrichous
The most immediate result of destruction of a cell's ribosomes would be
destruction of the cell's DNA.
material would not be able to cross the cell membrane.
loss of capsule.
protein synthesis would stop.
formation of glycogen inclusions. ------- Correct Ans ---------- protein synthesis would stop.
Which of the following, pertaining to prokaryotic cell membranes, is mismatched?
sterols present - mycoplasmas
unique hydrocarbon present - cyanobacteria
function - regulates transport of nutrients and wastes
internal folds - mesosomes
form a bilayer - phospholipids ------- Correct Ans ---------- unique hydrocarbon present -
cyanobacteria
In the Gram stain, the mordant is
Safranin.
Crystal Violet.
Water.
,Iodine.
Alcohol. ------- Correct Ans ---------- Iodine.
Endospores are
metabolically inactive.
resistant to heat and chemical destruction.
resistant to destruction by radiation.
living structures.
All of the choices are correct. ------- Correct Ans ---------- All of the choices are correct.
The site/s for most ATP synthesis in prokaryotic cells is/are the
cell membrane.
inclusions.
cell wall.
ribosomes.
mitochondria. ------- Correct Ans ---------- cell membrane.
The transfer of genes during bacterial conjugation involves rigid, tubular appendages called
periplasmic flagella (axial filaments).
fimbriae.
sex pili.
flagella.
cilia. ------- Correct Ans ---------- sex pili.
Bacterial endospores are not produced by
Sporosarcina.
Bacillus.
, All of the choices are correct.
Staphylococcus.
Clostridium. ------- Correct Ans ---------- Staphylococcus.
Which of the following characteristics is not a property of cells or living things?
Nucleus
All of the choices are correct
Cell boundary
Ability to replicate
Responds to stimulus ------- Correct Ans ---------- Nucles
A bacterial genus that has waxy mycolic acid in the cell walls is
Salmonella.
Mycoplasma.
Mycobacterium.
Streptococcus.
Corynebacterium. ------- Correct Ans ---------- Mycobacterium
All of the following pertain to endotoxins, except they
can cause shock in the human body.
are found in acid fast bacterial cell walls.
are specific bacterial cell wall lipids.
can stimulate fever in the human body.
are involved in typhoid fever and some meningitis cases. ------- Correct Ans ---------- are found
in acid fast bacterial cell walls.
Which is mismatched?
Questions, Answers and Rationale
What is the correct sequence for a Gram stain?
Safranin, Crystal Violet, Gram's iodine, Alcohol
Crystal Violet, Safranin, Alcohol, Gram's iodine
Alcohol, Crystal Violet, Safranin, Gram's iodine
Crystal Violet, Gram's iodine, Alcohol, Safranin
Gram's Iodine, Crystal Violet, Alcohol, Safranin ------- Correct Ans ---------- Crystal Violet,
Gram's iodine, Alcohol, Safranin
Peptidoglycan is a unique macromolecule found in bacterial
cell membranes
capsules
slime layers
cell walls
inclusions ------- Correct Ans ---------- cell walls
Lysozyme, an enzyme found in tears, provides a natural defense against bacteria by
removing flagella.
removing the capsule from outside the cell.
hydrolyzing peptidoglycan in cell walls.
dissolving the cell membrane.
inhibiting protein synthesis. ------- Correct Ans ---------- hydrolyzing the peptidoglycan in cell
walls
,Bacteria with small bunches of flagella emerging from the same site are said to be
peritrichous.
amphitrichous.
lophotrichous.
monotrichous.
spirilla. ------- Correct Ans ---------- lophotrichous
The most immediate result of destruction of a cell's ribosomes would be
destruction of the cell's DNA.
material would not be able to cross the cell membrane.
loss of capsule.
protein synthesis would stop.
formation of glycogen inclusions. ------- Correct Ans ---------- protein synthesis would stop.
Which of the following, pertaining to prokaryotic cell membranes, is mismatched?
sterols present - mycoplasmas
unique hydrocarbon present - cyanobacteria
function - regulates transport of nutrients and wastes
internal folds - mesosomes
form a bilayer - phospholipids ------- Correct Ans ---------- unique hydrocarbon present -
cyanobacteria
In the Gram stain, the mordant is
Safranin.
Crystal Violet.
Water.
,Iodine.
Alcohol. ------- Correct Ans ---------- Iodine.
Endospores are
metabolically inactive.
resistant to heat and chemical destruction.
resistant to destruction by radiation.
living structures.
All of the choices are correct. ------- Correct Ans ---------- All of the choices are correct.
The site/s for most ATP synthesis in prokaryotic cells is/are the
cell membrane.
inclusions.
cell wall.
ribosomes.
mitochondria. ------- Correct Ans ---------- cell membrane.
The transfer of genes during bacterial conjugation involves rigid, tubular appendages called
periplasmic flagella (axial filaments).
fimbriae.
sex pili.
flagella.
cilia. ------- Correct Ans ---------- sex pili.
Bacterial endospores are not produced by
Sporosarcina.
Bacillus.
, All of the choices are correct.
Staphylococcus.
Clostridium. ------- Correct Ans ---------- Staphylococcus.
Which of the following characteristics is not a property of cells or living things?
Nucleus
All of the choices are correct
Cell boundary
Ability to replicate
Responds to stimulus ------- Correct Ans ---------- Nucles
A bacterial genus that has waxy mycolic acid in the cell walls is
Salmonella.
Mycoplasma.
Mycobacterium.
Streptococcus.
Corynebacterium. ------- Correct Ans ---------- Mycobacterium
All of the following pertain to endotoxins, except they
can cause shock in the human body.
are found in acid fast bacterial cell walls.
are specific bacterial cell wall lipids.
can stimulate fever in the human body.
are involved in typhoid fever and some meningitis cases. ------- Correct Ans ---------- are found
in acid fast bacterial cell walls.
Which is mismatched?
