GCSU Microbiology
GCSU (Bachoon) Microbiology Test 2 Study
Questions and Answers 100% Correct 2026
Graded A+
Why do we study microbial growth?
1) to prove what causes disease
2) for antibiotic susceptibility (how to kill)
3) for research
what are the physical aspects of microbial growth?
- temperature
- pH
- osmotic pressure
what are the 3 main groups microbes are classified into based on their optimum
temperature?
1) psychrophiles
2) mesophiles
3) thermophiles
psychrophiles
- cold loving microbes
- don't cause disease
- (-10 deg. C to 20 deg. C)
GCSU Microbiology
,GCSU Microbiology
what is a psychrotroph?
- organism that is capable of growth between 0 deg. C and 30 deg. C
mesophiles
- moderate temperature loving microbes, most common type
- (25 deg. C - 40 deg. C)
- these are human pathogens also include most of the common spoilage and disease
organisms.
- ex: 37 deg. C (the optimum temp. for many pathogenic bacteria)
thermophiles
GCSU Microbiology
, GCSU Microbiology
- heat loving microbes
- (40 deg. C - 70 deg. C)
- many can't grow at temps below 45 deg. C
- hyperthermophiles = (70 deg. C - 110 deg. C)
what temperature do pathogens grow at?
- human body temp. (37 degrees celsius)
what pH range do most bacteria grow best in?
- a narrow pH range
- neutral (6.5 - 7.5)
- very few grow below pH 4
- foods with low pH (cheese, pickles..) don't spoil easily)
What are some examples of bacteria that grow below pH 4?
- sulfur oxidizers
- H. pylori
____ have more H+ than ______
acids, bases
what is the osmotic pressure inside bacterial cells in an isotonic solution?
GCSU Microbiology
GCSU (Bachoon) Microbiology Test 2 Study
Questions and Answers 100% Correct 2026
Graded A+
Why do we study microbial growth?
1) to prove what causes disease
2) for antibiotic susceptibility (how to kill)
3) for research
what are the physical aspects of microbial growth?
- temperature
- pH
- osmotic pressure
what are the 3 main groups microbes are classified into based on their optimum
temperature?
1) psychrophiles
2) mesophiles
3) thermophiles
psychrophiles
- cold loving microbes
- don't cause disease
- (-10 deg. C to 20 deg. C)
GCSU Microbiology
,GCSU Microbiology
what is a psychrotroph?
- organism that is capable of growth between 0 deg. C and 30 deg. C
mesophiles
- moderate temperature loving microbes, most common type
- (25 deg. C - 40 deg. C)
- these are human pathogens also include most of the common spoilage and disease
organisms.
- ex: 37 deg. C (the optimum temp. for many pathogenic bacteria)
thermophiles
GCSU Microbiology
, GCSU Microbiology
- heat loving microbes
- (40 deg. C - 70 deg. C)
- many can't grow at temps below 45 deg. C
- hyperthermophiles = (70 deg. C - 110 deg. C)
what temperature do pathogens grow at?
- human body temp. (37 degrees celsius)
what pH range do most bacteria grow best in?
- a narrow pH range
- neutral (6.5 - 7.5)
- very few grow below pH 4
- foods with low pH (cheese, pickles..) don't spoil easily)
What are some examples of bacteria that grow below pH 4?
- sulfur oxidizers
- H. pylori
____ have more H+ than ______
acids, bases
what is the osmotic pressure inside bacterial cells in an isotonic solution?
GCSU Microbiology
