Nokea
Which structure protects bacteria from phagocytosis?
- A. Flagella
- B. Capsule
- C. Endospore
- D. Pili
Correct Answer: B
Rationale: The correct answer is B: Capsule. Capsules are a protective layer outside the bacterial cell wall that helps bacteria evade phagocytosis by immune cells. The capsule inhibits phagocytic cells from engulfing the bacteria, making it difficult for them to be recognized and destroyed.
A: Flagella - Flagella are not involved in protecting bacteria from phagocytosis. They are responsible for bacterial movement.
C: Endospore - Endospores are dormant, resistant structures formed by some bacteria in response to harsh conditions. They do not directly protect against phagocytosis.
D: Pili - Pili are hair-like structures used for adhesion and conjugation, not for protection against phagocytosis.
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The cleaning of glassware and tableware in restaurants falls into the category of
- A. degermation.
- B. sterilization.
- C. disinfection.
- D. sanitization.
Correct Answer: D
Rationale: The correct answer is D: sanitization. Sanitization is the process of reducing the number of microorganisms on surfaces to a safe level. In restaurants, cleaning glassware and tableware aims to eliminate harmful bacteria to prevent foodborne illnesses. Degermation (A) focuses on removing germs from a specific area, sterilization (B) eliminates all microorganisms, and disinfection (C) reduces the number of pathogens but may not completely eliminate them, making them less effective choices for this context.
Which bacterium is known for producing an exotoxin that causes severe diarrhea?
- A. Clostridium tetani
- B. Clostridium botulinum
- C. Vibrio cholerae
- D. Shigella dysenteriae
Correct Answer: C
Rationale: Rationale:
1. Vibrio cholerae produces cholera toxin causing severe diarrhea.
2. Clostridium tetani causes tetanus, not diarrhea.
3. Clostridium botulinum causes botulism, not diarrhea.
4. Shigella dysenteriae causes dysentery, not typical diarrhea.
Summary:
A: Incorrect, causes tetanus.
B: Incorrect, causes botulism.
C: Correct, produces cholera toxin causing severe diarrhea.
D: Incorrect, causes dysentery.
For prevention of tuberculosis is used
- A. specific anti-tuberculosis serum
- B. BCG
- C. DTP
- D. PPD
Correct Answer: B
Rationale: The correct answer is B: BCG. Bacille Calmette-Guérin (BCG) vaccine is used for the prevention of tuberculosis. BCG is a live attenuated strain of Mycobacterium bovis that helps the immune system recognize and fight off tuberculosis bacteria. Specific anti-tuberculosis serum (A) is not used for prevention but for treatment. DTP (C) stands for diphtheria, tetanus, and pertussis vaccine, not specific for tuberculosis prevention. PPD (D) is a tuberculin skin test used for diagnosis, not prevention. Thus, BCG is the correct choice for tuberculosis prevention.
The spores of bacteria can be stained by:
- A. Methods of Romanovski-Gymsa
- B. Method of Ziehl-Nielsen
- C. Method of Moller
- D. Method of Neisser
Correct Answer: C
Rationale: The correct answer is C: Method of Moller. This method uses malachite green to stain bacterial spores due to their resistance to decolorization. The other choices, A, B, and D, are incorrect because Romanovski-Gymsa is used for staining blood smears, Ziehl-Nielsen is used for acid-fast bacteria, and Neisser is used for staining Neisseria species, not bacterial spores.
Stroma is a component of:
- A. chloroplasts
- B. mitochondria
- C. mitochondria
- D. lysosomes
Correct Answer: B
Rationale: The correct answer is B: mitochondria. Stroma is a component of chloroplasts, not mitochondria. Lysosomes contain hydrolytic enzymes, not stroma. Mitochondria have an inner and outer membrane structure, with the matrix containing the stroma where important metabolic processes occur. This is where the Krebs cycle and oxidative phosphorylation take place. Stroma in chloroplasts is where photosynthesis occurs. So, the correct answer is B because stroma is a component of mitochondria, where crucial energy production processes happen.