Nokea
A toxic, odorless gas often used as a sterilizing agent in hospitals and dental officials is
- A. ethylene oxide.
- B. carbon dioxide.
- C. carbon monoxide.
- D. propane.
Correct Answer: A
Rationale: The correct answer is A: ethylene oxide. Ethylene oxide is a toxic, odorless gas commonly used as a sterilizing agent in healthcare settings due to its ability to effectively kill bacteria, viruses, and fungi. It is a highly reactive compound that can penetrate porous materials, making it an ideal choice for sterilization purposes.
Incorrect choices:
B: Carbon dioxide is not used as a sterilizing agent and is not toxic.
C: Carbon monoxide is not commonly used for sterilization and has a distinct odor.
D: Propane is not used for sterilization in healthcare settings and is not odorless.
You may also like to solve these questions
Which bacteria is known for causing tuberculosis?
- A. Mycobacterium tuberculosis
- B. Mycobacterium leprae
- C. Escherichia coli
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Mycobacterium tuberculosis. This bacterium is known for causing tuberculosis, as it specifically infects the lungs and can lead to serious respiratory issues. Mycobacterium leprae (Choice B) causes leprosy, not tuberculosis. Escherichia coli (Choice C) is a common bacteria found in the intestines and is not associated with tuberculosis. Streptococcus pneumoniae (Choice D) causes pneumonia, but not tuberculosis. Therefore, the correct choice is A because Mycobacterium tuberculosis is the specific bacterium responsible for causing tuberculosis.
What is a common characteristic of spore-forming bacteria?
- A. Resistance to heat and dehydration
- B. Ability to produce toxins
- C. Presence of flagella
- D. Ability to photosynthesize
Correct Answer: A
Rationale: The correct answer is A: Resistance to heat and dehydration. Spore-forming bacteria form spores as a survival mechanism in harsh conditions. These spores are highly resistant to heat and dehydration, allowing the bacteria to withstand extreme environments. This characteristic is essential for their long-term survival and ability to persist in unfavorable conditions. Choices B, C, and D are incorrect because not all spore-forming bacteria produce toxins, have flagella, or are capable of photosynthesis. These characteristics are not exclusive to spore-forming bacteria and do not define them as a group.
The classic causative agent of croupous pneumonia is:
- A. Chlamydia pneumoniae
- B. Streptococcus pneumoniae
- C. Mycoplasmas pneumoniae
- D. Staphylococcus aureus
Correct Answer: B
Rationale: The correct answer is B, Streptococcus pneumoniae. This bacterium is the classic causative agent of croupous pneumonia due to its ability to infect the lungs and cause inflammation. Streptococcus pneumoniae is a common pathogen known for causing pneumonia in both adults and children. It is characterized by the presence of a capsule that helps it evade the host immune system.
Choice A, Chlamydia pneumoniae, is not the correct answer as it is more commonly associated with atypical pneumonia. Choice C, Mycoplasma pneumoniae, is also associated with atypical pneumonia and not croupous pneumonia. Choice D, Staphylococcus aureus, can cause pneumonia, but it is not the classic causative agent of croupous pneumonia.
Patients after transplantation of allogeneic stem cells are monitored periodically for reactivation of
- A. HAV
- B. CMV
- C. Rubella virus
- D. Measles virus
Correct Answer: B
Rationale: The correct answer is B: CMV. Patients after allogeneic stem cell transplantation are monitored for CMV reactivation due to its potential to cause severe complications in immunocompromised individuals. CMV can lead to organ damage and even mortality in these patients. Monitoring for CMV reactivation allows for early detection and prompt intervention.
Incorrect Choices:
A: HAV - Hepatitis A virus reactivation is not commonly monitored in post-transplant patients.
C: Rubella virus - Rubella is not a common concern for reactivation in this patient population.
D: Measles virus - Measles reactivation is not typically monitored in these patients.
Which structure allows bacteria to survive in adverse conditions?
- A. Flagella
- B. Capsule
- C. Endospore
- D. Pili
Correct Answer: C
Rationale: The correct answer is C: Endospore. Endospores are dormant, tough, and non-reproductive structures formed by certain bacteria as a response to unfavorable conditions. They help bacteria survive harsh environments such as extreme temperatures, desiccation, and exposure to harmful chemicals. The other choices, Flagella (A), Capsule (B), and Pili (D), do not directly contribute to bacterial survival in adverse conditions. Flagella aid in bacterial movement, capsules provide protection from immune system attacks, and pili are involved in attachment to surfaces or other cells. Endospores are specifically designed for survival during unfavorable conditions, making them the correct choice in this scenario.