,BIOD 171 Lab Exam 2 | Essential Microbiology
w/Lab | Portage Learning | Q & A | 2026 Edition
1. What three elements are used in an autoclave to sterilize equipment?
A) Heat, pressure, and steam
B) Heat, pressure, and dry air
C) Heat, steam, and time
D) Pressure, steam, and chemicals
Correct Answer: Heat, pressure, and steam
Rationale: An autoclave relies on the combination of heat, pressure, and steam to achieve sterilization.
The steam penetrates materials while the pressure allows the temperature to rise above the boiling
point of water, effectively killing all microorganisms.
2. What is the minimum temperature an autoclave must be set at to achieve a sterile condition?
A) 100°C
B) 121°C
C) 125°C
D) 134°C
Correct Answer: 125°C
Rationale: To achieve sterilization, an autoclave must reach a minimum temperature of 125°C. At this
temperature under standard pressure, all vegetative cells and most endospores are destroyed within a
specific time frame.
3. If an autoclave is not available and you are pressed for time, which method would best sterilize your
equipment?
A) Hot air
B) Hot steam
,C) Boiling water
D) Chemical disinfection
Correct Answer: Hot steam
Rationale: Hot steam is the best choice because it can achieve a sterile environment in a matter of
minutes, whereas hot air takes several hours to achieve the same effect. Steam transfers heat more
efficiently and penetrates materials better.
4. At what temperature is the fixed incubator typically set, as presented in the lab videos?
A) 25°C
B) 30°C
C) 37°C
D) 42°C
Correct Answer: 37°C
Rationale: The fixed incubator is typically set to 37°C, which is the optimal growth temperature for many
mesophilic microorganisms, including those that are pathogenic to humans and commonly studied in lab
settings.
5. At what temperature should you refrigerate bacterial samples, and why is this beneficial?
A) 4°C; it speeds up bacterial growth
B) 4°C; it slows bacterial growth and prolongs the life of the sample
C) -20°C; it stops all bacterial growth
D) 10°C; it maintains the sample's viability
Correct Answer: 4°C; it slows bacterial growth and prolongs the life of the sample
, Rationale: Refrigeration at 4°C slows down bacterial metabolism, which prolongs the life of the sample.
This is beneficial for short-term storage without killing the bacteria.
6. What are the FOUR types of gloves presented in the lab video?
A) Latex, Nitrile, Vinyl, and Rubber
B) Latex, Nitrile, Thermal cold, and Thermal heat
C) Nitrile, Rubber, Thermal cold, and Thermal heat
D) Latex, Vinyl, Thermal cold, and Thermal heat
Correct Answer: Latex, Nitrile, Thermal cold, and Thermal heat
Rationale: The four types of gloves highlighted in the lab video are latex, nitrile, thermal cold, and
thermal heat. Each type serves a specific purpose, from general protection to handling extreme
temperatures.
7. Which THREE rules were discussed in regards to lab safety that would protect you and others from
contamination?
A) Wear gloves, wash hands, and sterilize equipment
B) Never eat or drink in the lab, always wear appropriate PPE, and never leave the lab wearing PPE
C) Wear a lab coat, use a fume hood, and dispose of waste properly
D) Always wear goggles, tie back hair, and report spills
Correct Answer: Never eat or drink in the lab, always wear appropriate PPE, and never leave the lab
wearing PPE
Rationale: The three key lab safety rules to prevent contamination are: never eat or drink in the lab,
always wear appropriate personal protective equipment (PPE), and never leave the lab while wearing
PPE to avoid spreading contaminants.
8. What are the main sections that should be found in a lab notebook? (Name at least four.)
A) Title, Introduction, Methods, Results, Discussion
w/Lab | Portage Learning | Q & A | 2026 Edition
1. What three elements are used in an autoclave to sterilize equipment?
A) Heat, pressure, and steam
B) Heat, pressure, and dry air
C) Heat, steam, and time
D) Pressure, steam, and chemicals
Correct Answer: Heat, pressure, and steam
Rationale: An autoclave relies on the combination of heat, pressure, and steam to achieve sterilization.
The steam penetrates materials while the pressure allows the temperature to rise above the boiling
point of water, effectively killing all microorganisms.
2. What is the minimum temperature an autoclave must be set at to achieve a sterile condition?
A) 100°C
B) 121°C
C) 125°C
D) 134°C
Correct Answer: 125°C
Rationale: To achieve sterilization, an autoclave must reach a minimum temperature of 125°C. At this
temperature under standard pressure, all vegetative cells and most endospores are destroyed within a
specific time frame.
3. If an autoclave is not available and you are pressed for time, which method would best sterilize your
equipment?
A) Hot air
B) Hot steam
,C) Boiling water
D) Chemical disinfection
Correct Answer: Hot steam
Rationale: Hot steam is the best choice because it can achieve a sterile environment in a matter of
minutes, whereas hot air takes several hours to achieve the same effect. Steam transfers heat more
efficiently and penetrates materials better.
4. At what temperature is the fixed incubator typically set, as presented in the lab videos?
A) 25°C
B) 30°C
C) 37°C
D) 42°C
Correct Answer: 37°C
Rationale: The fixed incubator is typically set to 37°C, which is the optimal growth temperature for many
mesophilic microorganisms, including those that are pathogenic to humans and commonly studied in lab
settings.
5. At what temperature should you refrigerate bacterial samples, and why is this beneficial?
A) 4°C; it speeds up bacterial growth
B) 4°C; it slows bacterial growth and prolongs the life of the sample
C) -20°C; it stops all bacterial growth
D) 10°C; it maintains the sample's viability
Correct Answer: 4°C; it slows bacterial growth and prolongs the life of the sample
, Rationale: Refrigeration at 4°C slows down bacterial metabolism, which prolongs the life of the sample.
This is beneficial for short-term storage without killing the bacteria.
6. What are the FOUR types of gloves presented in the lab video?
A) Latex, Nitrile, Vinyl, and Rubber
B) Latex, Nitrile, Thermal cold, and Thermal heat
C) Nitrile, Rubber, Thermal cold, and Thermal heat
D) Latex, Vinyl, Thermal cold, and Thermal heat
Correct Answer: Latex, Nitrile, Thermal cold, and Thermal heat
Rationale: The four types of gloves highlighted in the lab video are latex, nitrile, thermal cold, and
thermal heat. Each type serves a specific purpose, from general protection to handling extreme
temperatures.
7. Which THREE rules were discussed in regards to lab safety that would protect you and others from
contamination?
A) Wear gloves, wash hands, and sterilize equipment
B) Never eat or drink in the lab, always wear appropriate PPE, and never leave the lab wearing PPE
C) Wear a lab coat, use a fume hood, and dispose of waste properly
D) Always wear goggles, tie back hair, and report spills
Correct Answer: Never eat or drink in the lab, always wear appropriate PPE, and never leave the lab
wearing PPE
Rationale: The three key lab safety rules to prevent contamination are: never eat or drink in the lab,
always wear appropriate personal protective equipment (PPE), and never leave the lab while wearing
PPE to avoid spreading contaminants.
8. What are the main sections that should be found in a lab notebook? (Name at least four.)
A) Title, Introduction, Methods, Results, Discussion
