Nokea
Which structure in bacteria is used for attachment to surfaces?
- A. Flagella
- B. Fimbriae
- C. Pili
- D. Capsule
Correct Answer: B
Rationale: The correct answer is B: Fimbriae. Fimbriae are short, hair-like appendages on the surface of bacteria that help in attachment to surfaces. They aid in colonization and biofilm formation. Flagella (A) are used for motility. Pili (C) are longer appendages used for conjugation and adherence to other cells. Capsules (D) are protective structures that aid in evading the host immune system, not necessarily for attachment.
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The causative agent of plague is:
- A. Bordetella pertussis
- B. Yersinia pestis
- C. Rickettsia prowazekii
- D. Treponema pallidum
Correct Answer: B
Rationale: The correct answer is B: Yersinia pestis. Y. pestis is the causative agent of plague, a serious infectious disease transmitted through fleas. It causes bubonic, pneumonic, and septicemic plague. Bordetella pertussis causes whooping cough, Rickettsia prowazekii causes epidemic typhus, and Treponema pallidum causes syphilis. Y. pestis is the correct answer because it is specifically associated with plague, making the other options incorrect.
Which bacteria are associated with causing foodborne infections?
- A. Clostridium botulinum
- B. Escherichia coli
- C. Salmonella enterica
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D (All of the above) because all three bacteria (Clostridium botulinum, Escherichia coli, Salmonella enterica) are known to cause foodborne infections. Clostridium botulinum can lead to botulism, E. coli can cause various gastrointestinal illnesses, and Salmonella enterica is a common cause of food poisoning. Each bacterium has specific mechanisms that result in foodborne illnesses. Choices A, B, and C are incorrect because each bacterium mentioned is associated with causing foodborne infections, making them collectively the correct answer.
There are several cases of children from boarding school suffering from sore throat. Microscopy of tonsil smears stained according Neisser method has revealed thin yellow bacilli with dark brown grains on their ends placed in the shape of Roman numeral five. What infection can be suspected in this case?
- A. Diphtheria
- B. Scarlet fever
- C. Listeriosis
- D. Tonsilitis
Correct Answer: A
Rationale: Rationale for Correct Answer A (Diphtheria):
1. Thin yellow bacilli with dark brown grains on ends suggest Corynebacterium diphtheriae, characteristic of diphtheria.
2. Roman numeral five shape is typical of diphtheria bacilli.
3. Diphtheria causes sore throat and can spread in boarding schools.
4. Neisser staining method is used for diphtheria bacilli.
Summary of Incorrect Choices:
B: Scarlet fever is caused by Streptococcus pyogenes and presents with rash, not yellow bacilli.
C: Listeriosis is caused by Listeria monocytogenes, not consistent with the described findings.
D: Tonsillitis can be caused by various bacteria or viruses, but the specific characteristics described do not match.
What type of bacteria is responsible for the formation of acid in the stomach?
- A. Staphylococcus aureus
- B. Helicobacter pylori
- C. Bacillus cereus
- D. Clostridium botulinum
Correct Answer: B
Rationale: The correct answer is B: Helicobacter pylori. This bacterium is responsible for stomach acid formation by producing an enzyme called urease, which converts urea into ammonia and carbon dioxide, leading to an increase in stomach pH. Staphylococcus aureus (A) does not cause stomach acid formation. Bacillus cereus (C) and Clostridium botulinum (D) are not involved in stomach acid processes.
Which of the following viruses could be reactivated under immunosuppressive therapy?
- A. Virus Parotitidis
- B. Rubella virus
- C. Influenza A
- D. None of the above
Correct Answer: D
Rationale: The correct answer is D, "None of the above," because viruses like Parotitidis (mumps), Rubella, and Influenza A are not typically associated with reactivation under immunosuppressive therapy. Reactivation is more commonly seen in latent viruses like herpesviruses (e.g., herpes simplex, varicella-zoster), cytomegalovirus, and Epstein-Barr virus. These viruses can remain dormant in the body and reactivate when the immune system is compromised. Therefore, the correct answer is D, as the viruses mentioned in choices A, B, and C do not fit the criteria for reactivation under immunosuppressive therapy.