CH. 9 – Microbial Growth and Control
9.1 Requirements for Microbial Growth
EASY
1. The difference in potential growth rates between cell types is amazing: it takes nine months for a
human fertilized egg to develop into a human baby. But this is a creeping pace of growth when compared
to a bacterium that can potentially go from 1 cell into a pile of cells the same size as a human infant in
__________ hours.
a. 10 b. 12 c. 15 D. 17 e. 20
EASY
2. Microbial growth refers to
a. growth in size of an individual cell
b. growth in size of a cluster of cells
C. growth in number of cells of regular size
d. growth in number of cells of expanding size
MEDIUM
3. Microbial growth either in a natural environment or in a laboratory requires these physical
requirements:
a. proper pH
b. appropriate ambient temperature
c. correct osmolarity
D. all of these
e. only answers a and b are correct
HARD
4. Chemical requirements for microbial growth include which of the following?
a. carbon source for all microbes
b. oxygen source for some microbes
c. nitrogen source for all microbes
d. phosphorus source for all microbes
E. all of these are correct
MEDIUM
5. Most microorganisms belong to which of the following categories?
a. photoheterotrophs
b. photoautotrophs
C. chemoheterotrophs
d. chemoautotrophs
EASY
6. The measure of acidity in a microbe’s environment is measured by pH and is important because it can
affect so many of the chemical reactions inside the cell, like chemical bonding and enzyme function. Most
microbes generally prefer a pH range of
a. 3.0 to 8.0
B. 6.5 to 7.5
c. 5.5 to 8.5
d. 6.5 to 8.5
, 2
HARD
7. For thousands of years humans have utilized the principles of acidity in food items as a way of
preserving food in the absence of refrigeration. Which of the following cellular processes that you have
already studied produces acidic products that will preserve food?
A. Fermentation
b. Aerobic respiration
c. Anaerobic respiration
d. Glycolysis
MEDIUM
8. Which of the following microorganisms actually prefer a more optimum acidic environment of 5 to 6
pH?
a. bacteria
B. fungi
c. protozoa
d. viruses
e. algae
EASY
9. All of the following are correct pairings of terms and their definitions except ___________
a. minimum growth temperature/lowest temperature that supports growth
b. optimum growth temperature/temperature at which the most cells are produced
c. maximum growth temperature/highest temperature that supports growth
D. sustained growth temperature/temperature at which growth is barely supported
EASY
10. Match the term describing a microbe’s preferred temperature range with the temperature in Celsius:
Preferred Temperature Range Temperature in Celsius
Psychrophile C a. above 80 degrees
Mesophile B b. between 15 and 30 degrees
Thermophile D c. below 15 degrees
Hyperthermophile A d. above 50 degrees
HARD
11. Which of the following cell types cannot protect itself from bursting when placed in a hypotonic
environment?
A. animal cell
b. bacteria
c. fungi
d. protozoa
e. all of these
EASY
12. In a hypertonic environment, which way will water flow via osmosis?
a. into the cell
B. out of the cell
c. neither since movement of water particles in and out of the cell will be equal
d. none of these
MEDIUM
9.1 Requirements for Microbial Growth
EASY
1. The difference in potential growth rates between cell types is amazing: it takes nine months for a
human fertilized egg to develop into a human baby. But this is a creeping pace of growth when compared
to a bacterium that can potentially go from 1 cell into a pile of cells the same size as a human infant in
__________ hours.
a. 10 b. 12 c. 15 D. 17 e. 20
EASY
2. Microbial growth refers to
a. growth in size of an individual cell
b. growth in size of a cluster of cells
C. growth in number of cells of regular size
d. growth in number of cells of expanding size
MEDIUM
3. Microbial growth either in a natural environment or in a laboratory requires these physical
requirements:
a. proper pH
b. appropriate ambient temperature
c. correct osmolarity
D. all of these
e. only answers a and b are correct
HARD
4. Chemical requirements for microbial growth include which of the following?
a. carbon source for all microbes
b. oxygen source for some microbes
c. nitrogen source for all microbes
d. phosphorus source for all microbes
E. all of these are correct
MEDIUM
5. Most microorganisms belong to which of the following categories?
a. photoheterotrophs
b. photoautotrophs
C. chemoheterotrophs
d. chemoautotrophs
EASY
6. The measure of acidity in a microbe’s environment is measured by pH and is important because it can
affect so many of the chemical reactions inside the cell, like chemical bonding and enzyme function. Most
microbes generally prefer a pH range of
a. 3.0 to 8.0
B. 6.5 to 7.5
c. 5.5 to 8.5
d. 6.5 to 8.5
, 2
HARD
7. For thousands of years humans have utilized the principles of acidity in food items as a way of
preserving food in the absence of refrigeration. Which of the following cellular processes that you have
already studied produces acidic products that will preserve food?
A. Fermentation
b. Aerobic respiration
c. Anaerobic respiration
d. Glycolysis
MEDIUM
8. Which of the following microorganisms actually prefer a more optimum acidic environment of 5 to 6
pH?
a. bacteria
B. fungi
c. protozoa
d. viruses
e. algae
EASY
9. All of the following are correct pairings of terms and their definitions except ___________
a. minimum growth temperature/lowest temperature that supports growth
b. optimum growth temperature/temperature at which the most cells are produced
c. maximum growth temperature/highest temperature that supports growth
D. sustained growth temperature/temperature at which growth is barely supported
EASY
10. Match the term describing a microbe’s preferred temperature range with the temperature in Celsius:
Preferred Temperature Range Temperature in Celsius
Psychrophile C a. above 80 degrees
Mesophile B b. between 15 and 30 degrees
Thermophile D c. below 15 degrees
Hyperthermophile A d. above 50 degrees
HARD
11. Which of the following cell types cannot protect itself from bursting when placed in a hypotonic
environment?
A. animal cell
b. bacteria
c. fungi
d. protozoa
e. all of these
EASY
12. In a hypertonic environment, which way will water flow via osmosis?
a. into the cell
B. out of the cell
c. neither since movement of water particles in and out of the cell will be equal
d. none of these
MEDIUM
