BIOD 171 | BIOD 171 Microbiology Module 9 Exam
| Questions with Correct Answers and Expert
Explanation for Each Question | Portage Learning
1. Which term describes the number of new cases of a specific disease in a population
over a defined period of time?
A. Prevalence
B. Morbidity
C. Mortality
D. Incidence
Correct Answer: D
Expert Explanation: Incidence is the measure of the risk of developing a new
condition within a specified period of time. It provides information about the rate at
which a disease is spreading through a community. This is distinct from prevalence,
which counts both old and new cases to show the total disease burden. Public health
officials monitor incidence to identify emerging outbreaks early. Tracking incidence
is essential for evaluating the success of preventative measures like vaccination
programs.
2. A disease that is constantly present in a specific geographic population at a low,
stable level is referred to as:
A. Epidemic
,B. Endemic
C. Pandemic
D. Sporadic
Correct Answer: B
Expert Explanation: Endemic diseases are those that have a steady presence
within a particular region or population group. Common examples include the
seasonal flu in temperate climates or malaria in tropical regions. Unlike epidemics,
endemic levels do not show a sudden or unexpected increase in cases.
Epidemiologists establish a baseline level to monitor these diseases effectively. If
the number of cases significantly exceeds this baseline, the status may change to an
epidemic.
3. What is the primary mode of transmission for a disease spread through
contaminated inanimate objects like doorknobs or towels?
A. Biological vector transmission
B. Direct contact transmission
C. Indirect contact via fomites
D. Droplet transmission
Correct Answer: C
,Expert Explanation: Indirect contact involves the transfer of pathogens through an
intermediate object called a fomite. Fomites can include medical equipment, toys, or
everyday surfaces that harbor infectious agents. This mode of transmission
highlights the importance of regular surface disinfection in healthcare settings.
Pathogens can survive on these surfaces for varying lengths of time depending on
environmental conditions. Effective hand hygiene and environmental cleaning are
critical strategies for breaking this chain of infection.
4. Which of the following processes is defined as the complete destruction or removal
of all viable microorganisms, including endospores and viruses?
A. Disinfection
B. Sanitization
C. Sterilization
D. Antisepsis
Correct Answer: C
Expert Explanation: Sterilization is the most rigorous level of microbial control
available in clinical and laboratory settings. It ensures that even the most resistant
life forms, such as bacterial endospores, are eliminated. Common methods for
achieving sterilization include autoclaving, dry heat, and chemical sterilants. This
process is mandatory for surgical instruments and items that penetrate sterile body
, tissues. Without successful sterilization, the risk of healthcare-associated infections
increases dramatically for patients.
5. The standard parameters for autoclaving to ensure sterilization of most items are:
A. 100°C at 10 psi for 60 minutes
B. 72°C for 15 seconds
C. 160°C for 2 hours
D. 121°C at 15 psi for 15-20 minutes
Correct Answer: D
Expert Explanation: The autoclave uses pressurized steam to achieve
temperatures higher than the boiling point of water. Maintaining 121°C at 15 psi is
the industry standard for general microbial destruction. The exposure time must be
sufficient to allow the heat to penetrate the entire load. This combination of heat
and pressure effectively denatures proteins and disrupts cell membranes. It is
considered the most reliable method for sterilizing laboratory media and clinical
tools.
6. A chemical agent that is applied directly to living tissue (such as skin) to inhibit or
destroy pathogens is called a(n):
A. Disinfectant
B. Antiseptic
| Questions with Correct Answers and Expert
Explanation for Each Question | Portage Learning
1. Which term describes the number of new cases of a specific disease in a population
over a defined period of time?
A. Prevalence
B. Morbidity
C. Mortality
D. Incidence
Correct Answer: D
Expert Explanation: Incidence is the measure of the risk of developing a new
condition within a specified period of time. It provides information about the rate at
which a disease is spreading through a community. This is distinct from prevalence,
which counts both old and new cases to show the total disease burden. Public health
officials monitor incidence to identify emerging outbreaks early. Tracking incidence
is essential for evaluating the success of preventative measures like vaccination
programs.
2. A disease that is constantly present in a specific geographic population at a low,
stable level is referred to as:
A. Epidemic
,B. Endemic
C. Pandemic
D. Sporadic
Correct Answer: B
Expert Explanation: Endemic diseases are those that have a steady presence
within a particular region or population group. Common examples include the
seasonal flu in temperate climates or malaria in tropical regions. Unlike epidemics,
endemic levels do not show a sudden or unexpected increase in cases.
Epidemiologists establish a baseline level to monitor these diseases effectively. If
the number of cases significantly exceeds this baseline, the status may change to an
epidemic.
3. What is the primary mode of transmission for a disease spread through
contaminated inanimate objects like doorknobs or towels?
A. Biological vector transmission
B. Direct contact transmission
C. Indirect contact via fomites
D. Droplet transmission
Correct Answer: C
,Expert Explanation: Indirect contact involves the transfer of pathogens through an
intermediate object called a fomite. Fomites can include medical equipment, toys, or
everyday surfaces that harbor infectious agents. This mode of transmission
highlights the importance of regular surface disinfection in healthcare settings.
Pathogens can survive on these surfaces for varying lengths of time depending on
environmental conditions. Effective hand hygiene and environmental cleaning are
critical strategies for breaking this chain of infection.
4. Which of the following processes is defined as the complete destruction or removal
of all viable microorganisms, including endospores and viruses?
A. Disinfection
B. Sanitization
C. Sterilization
D. Antisepsis
Correct Answer: C
Expert Explanation: Sterilization is the most rigorous level of microbial control
available in clinical and laboratory settings. It ensures that even the most resistant
life forms, such as bacterial endospores, are eliminated. Common methods for
achieving sterilization include autoclaving, dry heat, and chemical sterilants. This
process is mandatory for surgical instruments and items that penetrate sterile body
, tissues. Without successful sterilization, the risk of healthcare-associated infections
increases dramatically for patients.
5. The standard parameters for autoclaving to ensure sterilization of most items are:
A. 100°C at 10 psi for 60 minutes
B. 72°C for 15 seconds
C. 160°C for 2 hours
D. 121°C at 15 psi for 15-20 minutes
Correct Answer: D
Expert Explanation: The autoclave uses pressurized steam to achieve
temperatures higher than the boiling point of water. Maintaining 121°C at 15 psi is
the industry standard for general microbial destruction. The exposure time must be
sufficient to allow the heat to penetrate the entire load. This combination of heat
and pressure effectively denatures proteins and disrupts cell membranes. It is
considered the most reliable method for sterilizing laboratory media and clinical
tools.
6. A chemical agent that is applied directly to living tissue (such as skin) to inhibit or
destroy pathogens is called a(n):
A. Disinfectant
B. Antiseptic
