8/16/25, 10:56
AM
CRCST CHAPTER 4 MICROBIOLOGY EXAM QUESTIONS
AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
LATEST UPDATE GRADED A++ 2025/2026
Terms in this set (45)
Microbiology The study of microorganisms. The science which
treats the nature, like, and action of
microorganisms.
Contamination The state of being soiled or infected by contact
with infectious organisms or other material.
Pathogen Capable of causing disease (disease-causing
microorganisms).
Micron A unit of measurement; 1/1000 of a millimeter or
1/25,000 of an inch; usually designated by the
Greek letter u.
Aerobic Requires the presence of air of free oxygen to survive.
Anaerobic Bacteria that can live in the absence of atmospheric
oxygen.
Spherical, Rod, and Spiral The common different shapes of bacteria.
Endospores Microorganisms capable of forming a thick wall
around themselves enabling them to survive in
adverse conditions; a resistant form of
bacterium.
Gram Staining The type of staining used to determine the different
type of bacteria.
Purple The color of gram-positive bacteria such as
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AM
Staphylococcus.
Red The color of gram-negative bacteria such as
Pseudomonas.
Acid Fast (Ziehl-Neilson Used when rod-shaped acid-fast bacilli bacteria
Stain) that are very difficult to stain such as
mycobacteria.
pH Measure of alkalinity or acidity on a scale of 0 to 14.
Neutral pH of 7
Acid pH below 7
Alkaline pH above 7
Psychrophiles (bacteria) Bacteria whose optimum temperature for growth is 59
to 68 degrees or below.
Mesophiles (bacteria) Bacteria that grow best at moderate
temperatures of 68-113 degrees. Most are
pathogenic to humans as they grow best at
body temperature.
Thermophiles (bacteria) Bacteria that grow best at temperatures of 122-158
degrees.
Protoplasm A thick mucus-like substance that is
colorless and translucent that forms the
biochemical basis of life found within
the cell nucleus.
Cytoplasm The living matter of a cell between the cells membrane
and nucleus.
Cocci Round or Spherical-Shaped Bacteria
Bacillus Rod-Shaped Bacteria
Infection The invasion of human body tissue by
microorganisms which multiply and produce a
2/
5
AM
CRCST CHAPTER 4 MICROBIOLOGY EXAM QUESTIONS
AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
LATEST UPDATE GRADED A++ 2025/2026
Terms in this set (45)
Microbiology The study of microorganisms. The science which
treats the nature, like, and action of
microorganisms.
Contamination The state of being soiled or infected by contact
with infectious organisms or other material.
Pathogen Capable of causing disease (disease-causing
microorganisms).
Micron A unit of measurement; 1/1000 of a millimeter or
1/25,000 of an inch; usually designated by the
Greek letter u.
Aerobic Requires the presence of air of free oxygen to survive.
Anaerobic Bacteria that can live in the absence of atmospheric
oxygen.
Spherical, Rod, and Spiral The common different shapes of bacteria.
Endospores Microorganisms capable of forming a thick wall
around themselves enabling them to survive in
adverse conditions; a resistant form of
bacterium.
Gram Staining The type of staining used to determine the different
type of bacteria.
Purple The color of gram-positive bacteria such as
1/
5
, 8/16/25, 10:56
AM
Staphylococcus.
Red The color of gram-negative bacteria such as
Pseudomonas.
Acid Fast (Ziehl-Neilson Used when rod-shaped acid-fast bacilli bacteria
Stain) that are very difficult to stain such as
mycobacteria.
pH Measure of alkalinity or acidity on a scale of 0 to 14.
Neutral pH of 7
Acid pH below 7
Alkaline pH above 7
Psychrophiles (bacteria) Bacteria whose optimum temperature for growth is 59
to 68 degrees or below.
Mesophiles (bacteria) Bacteria that grow best at moderate
temperatures of 68-113 degrees. Most are
pathogenic to humans as they grow best at
body temperature.
Thermophiles (bacteria) Bacteria that grow best at temperatures of 122-158
degrees.
Protoplasm A thick mucus-like substance that is
colorless and translucent that forms the
biochemical basis of life found within
the cell nucleus.
Cytoplasm The living matter of a cell between the cells membrane
and nucleus.
Cocci Round or Spherical-Shaped Bacteria
Bacillus Rod-Shaped Bacteria
Infection The invasion of human body tissue by
microorganisms which multiply and produce a
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