BIOS 242: EXAM 2 CHAMBERLAIN ACTUAL EXAM
PREP 2026 150 QUESTIONS AND CORRECT
DETAILED ANSWERS ALREADY A GRADED WITH
EXPERT FEEDBACK|NEW AND REVISED
BIOS 242: Exam 2 Chamberlain – Practice Exam
PART 1: MICROBIAL NUTRITION & GROWTH
1. An organism that uses inorganic CO₂ as its carbon source and gains energy
from chemical compounds is classified as:
A) Photoautotroph
B) Chemoautotroph
C) Photoheterotroph
D) Chemoheterotroph
Correct Answer: B) Chemoautotroph
Rationale: Chemoautotrophs use CO₂ as a carbon source and obtain energy from
chemical compounds (e.g., nitrifying bacteria). Photoautotrophs use light energy.
Photoheterotrophs use light energy but require organic carbon sources .
2. Most human pathogens are classified as which of the following based on their
temperature growth range?
A) Psychrophiles
B) Mesophiles
C) Thermophiles
D) Hyperthermophiles
Correct Answer: B) Mesophiles
,Rationale: Mesophiles grow optimally at moderate temperatures (20°C-40°C) and
include most human pathogens, which grow best near body temperature (37°C) .
Psychrophiles grow at cold temperatures (0-15°C), while thermophiles grow at
high temperatures (45-80°C) .
3. A microorganism that requires a high concentration of salt (9-25% NaCl) for
growth is called a:
A) Barophile
B) Halophile
C) Acidophile
D) Psychrophile
Correct Answer: B) Halophile
Rationale: Halophiles require high salt concentrations for growth. Obligate
halophiles inhabit environments like the Dead Sea . Barophiles require high
hydrostatic pressure, acidophiles grow in acidic environments, and psychrophiles
grow at cold temperatures .
4. Which type of organism can grow in the presence of oxygen but does not
require it?
A) Obligate aerobe
B) Obligate anaerobe
C) Aerotolerant anaerobe
D) Microaerophile
Correct Answer: C) Aerotolerant anaerobe
Rationale: Aerotolerant anaerobes can grow in the presence of oxygen but do not
use it for metabolism. Obligate aerobes require oxygen, obligate anaerobes are
killed by oxygen, and microaerophiles require small amounts of oxygen .
, 5. The correct sequence of the bacterial growth curve is:
A) Lag, Stationary, Log (Exponential), Death
B) Lag, Log (Exponential), Stationary, Death
C) Log, Lag, Stationary, Death
D) Stationary, Lag, Log, Death
Correct Answer: B) Lag, Log (Exponential), Stationary, Death
Rationale: The growth curve phases occur in this order: Lag phase (adjustment, no
growth), Log/Exponential phase (rapid cell division), Stationary phase (growth =
death), and Death phase (cell death exceeds growth) .
6. During which phase of the bacterial growth curve are cells most susceptible to
antimicrobial agents?
A) Lag phase
B) Log (Exponential) phase
C) Stationary phase
D) Death phase
Correct Answer: B) Log (Exponential) phase
Rationale: Cells in the log phase are actively dividing and metabolically active,
making them most susceptible to antimicrobial agents. In the lag phase, cells are
adjusting but not yet dividing rapidly.
7. The transport of molecules across the cell membrane from an area of higher
concentration to an area of lower concentration without the use of energy is
called:
A) Active transport
B) Facilitated diffusion
C) Passive diffusion
D) Endocytosis
PREP 2026 150 QUESTIONS AND CORRECT
DETAILED ANSWERS ALREADY A GRADED WITH
EXPERT FEEDBACK|NEW AND REVISED
BIOS 242: Exam 2 Chamberlain – Practice Exam
PART 1: MICROBIAL NUTRITION & GROWTH
1. An organism that uses inorganic CO₂ as its carbon source and gains energy
from chemical compounds is classified as:
A) Photoautotroph
B) Chemoautotroph
C) Photoheterotroph
D) Chemoheterotroph
Correct Answer: B) Chemoautotroph
Rationale: Chemoautotrophs use CO₂ as a carbon source and obtain energy from
chemical compounds (e.g., nitrifying bacteria). Photoautotrophs use light energy.
Photoheterotrophs use light energy but require organic carbon sources .
2. Most human pathogens are classified as which of the following based on their
temperature growth range?
A) Psychrophiles
B) Mesophiles
C) Thermophiles
D) Hyperthermophiles
Correct Answer: B) Mesophiles
,Rationale: Mesophiles grow optimally at moderate temperatures (20°C-40°C) and
include most human pathogens, which grow best near body temperature (37°C) .
Psychrophiles grow at cold temperatures (0-15°C), while thermophiles grow at
high temperatures (45-80°C) .
3. A microorganism that requires a high concentration of salt (9-25% NaCl) for
growth is called a:
A) Barophile
B) Halophile
C) Acidophile
D) Psychrophile
Correct Answer: B) Halophile
Rationale: Halophiles require high salt concentrations for growth. Obligate
halophiles inhabit environments like the Dead Sea . Barophiles require high
hydrostatic pressure, acidophiles grow in acidic environments, and psychrophiles
grow at cold temperatures .
4. Which type of organism can grow in the presence of oxygen but does not
require it?
A) Obligate aerobe
B) Obligate anaerobe
C) Aerotolerant anaerobe
D) Microaerophile
Correct Answer: C) Aerotolerant anaerobe
Rationale: Aerotolerant anaerobes can grow in the presence of oxygen but do not
use it for metabolism. Obligate aerobes require oxygen, obligate anaerobes are
killed by oxygen, and microaerophiles require small amounts of oxygen .
, 5. The correct sequence of the bacterial growth curve is:
A) Lag, Stationary, Log (Exponential), Death
B) Lag, Log (Exponential), Stationary, Death
C) Log, Lag, Stationary, Death
D) Stationary, Lag, Log, Death
Correct Answer: B) Lag, Log (Exponential), Stationary, Death
Rationale: The growth curve phases occur in this order: Lag phase (adjustment, no
growth), Log/Exponential phase (rapid cell division), Stationary phase (growth =
death), and Death phase (cell death exceeds growth) .
6. During which phase of the bacterial growth curve are cells most susceptible to
antimicrobial agents?
A) Lag phase
B) Log (Exponential) phase
C) Stationary phase
D) Death phase
Correct Answer: B) Log (Exponential) phase
Rationale: Cells in the log phase are actively dividing and metabolically active,
making them most susceptible to antimicrobial agents. In the lag phase, cells are
adjusting but not yet dividing rapidly.
7. The transport of molecules across the cell membrane from an area of higher
concentration to an area of lower concentration without the use of energy is
called:
A) Active transport
B) Facilitated diffusion
C) Passive diffusion
D) Endocytosis
