Nokea
The cytoplasmic membrane of the eukaryotes, in contrast to the one of prokaryotes, has:
- A. cellulose
- B. starch
- C. chitin
- D. sterols
Correct Answer: D
Rationale: The correct answer is D: sterols. Eukaryotic cytoplasmic membranes contain sterols, such as cholesterol, which provide stability and regulate fluidity. This is a key characteristic that distinguishes them from prokaryotic membranes. Cellulose (A) is a component of plant cell walls, not the cytoplasmic membrane. Starch (B) is a carbohydrate used for energy storage in plants. Chitin (C) is a component of fungal cell walls and arthropod exoskeletons, not found in eukaryotic cytoplasmic membranes.
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Which bacteria produce urease enzyme to neutralize stomach acid?
- A. Salmonella typhi
- B. Escherichia coli
- C. Helicobacter pylori
- D. Shigella flexneri
Correct Answer: C
Rationale: Rationale:
1. Helicobacter pylori is known for producing urease enzyme to neutralize stomach acid.
2. Urease enzyme converts urea into ammonia, buffering the acidic pH.
3. This adaptation allows H. pylori to survive in the acidic environment of the stomach.
4. Salmonella typhi, Escherichia coli, and Shigella flexneri do not produce urease.
5. Therefore, C is the correct answer based on the unique urease-producing capability of H. pylori.
During bacteriological examination of sputum of a child with choking cough and fever there were revealed glossy smooth colonies growing on casein-charcoal agar and reminding of mercury drops. Microscopic examination revealed short Gram-negative bacteria. What microorganism was secured from the sputum?
- A. Bordetella pertussis
- B. Haemophylus influenzae
- C. Corynebacterium dyphtheriae
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. Glossy smooth colonies growing on casein-charcoal agar resembling mercury drops indicate Bordetella pertussis, the causative agent of whooping cough. The presence of short Gram-negative bacteria further supports this identification. Option B, Haemophilus influenzae, typically grows as small, round, translucent colonies on chocolate agar. Option C, Corynebacterium diphtheriae, forms gray colonies on tellurite agar. Option D, Klebsiella pneumoniae, appears as mucoid colonies on MacConkey agar.
Decontamination is defined as the
- A. killing of all microorganisms in a given area.
- B. reduction or removal of unwanted chemical or biological agents.
- C. stopping of the growth of microorganisms in a given area.
- D. removal of all vegetative organisms.
Correct Answer: B
Rationale: Decontamination is the reduction or removal of unwanted chemical or biological agents to make an area safe. This includes cleaning, disinfecting, or sterilizing to eliminate harmful substances. Choice A is incorrect as decontamination doesn't necessarily involve killing all microorganisms. Choice C is incorrect as it focuses on stopping growth, not removing existing contaminants. Choice D is incorrect as it specifically mentions vegetative organisms, which may not cover all types of contaminants that need to be removed during decontamination. Thus, the correct answer is B as it accurately describes the process of decontamination.
Which of the following characteristics of mumps infection is NOT true:
- A. Only the person can be infected
- B. Is a vaccine-preventable disease
- C. Is a highly contagious disease
- D. Transmission routes are via air droplets and direct contact
Correct Answer: A
Rationale: Step-by-step rationale:
1. Mumps is a contagious disease transmitted through air droplets and direct contact.
2. The correct answer is A because mumps can infect both humans and animals.
3. Choice B is incorrect as mumps is vaccine-preventable.
4. Choice C is correct as mumps is highly contagious.
5. Choice D is accurate as mumps is transmitted via air droplets and direct contact.
Summary:
The correct answer is A because mumps can infect both humans and animals, making it untrue that only humans can be infected. Choices B, C, and D are incorrect as mumps is vaccine-preventable, highly contagious, and transmitted through air droplets and direct contact.
Which bacterium is known as a common cause of hospital-acquired infections?
- A. Clostridium botulinum
- B. Staphylococcus aureus
- C. Treponema pallidum
- D. Mycobacterium leprae
Correct Answer: B
Rationale: The correct answer is B: Staphylococcus aureus. This bacterium is known as a common cause of hospital-acquired infections due to its ability to colonize the skin and mucous membranes of healthcare workers and patients. Staphylococcus aureus can cause various infections, including surgical site infections and bloodstream infections, in healthcare settings.
Rationale:
1. Clostridium botulinum is known for causing foodborne botulism, not hospital-acquired infections.
2. Treponema pallidum causes syphilis, which is primarily transmitted through sexual contact, not hospital settings.
3. Mycobacterium leprae causes leprosy, which is not commonly associated with hospital-acquired infections.
In summary, Staphylococcus aureus is the correct answer as it is a common cause of hospital-acquired infections due to its prevalence in healthcare environments, unlike the other choices which are not typically associated with hospital-acquired infections.