Nokea
Cholera is a serious gastrointestinal illness caused by bacteria of the genus:
- A. Escherichia
- B. Salmonella
- C. Vibrio
- D. Acinetobacter
Correct Answer: C
Rationale: The correct answer is C: Vibrio. Cholera is caused by Vibrio cholerae bacteria. These bacteria produce a toxin that causes severe diarrhea and dehydration. Escherichia (choice A) and Salmonella (choice B) are known for causing other types of gastrointestinal infections but not cholera. Acinetobacter (choice D) typically causes respiratory infections, not gastrointestinal illnesses like cholera. Therefore, the correct choice is Vibrio as it is specifically associated with cholera.
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The food preparation process in which not all microorganisms are killed, but the number of microbes capable of spoiling the food or causing disease is reduced, is called
- A. sanitation.
- B. pasteurization.
- C. disinfection.
- D. purification.
Correct Answer: B
Rationale: The correct answer is B: pasteurization. This process involves heating food to a specific temperature to kill harmful bacteria while preserving the flavor and quality of the food. Sanitation (A) refers to maintaining cleanliness to prevent contamination. Disinfection (C) involves killing most, but not all, microbes on surfaces. Purification (D) typically refers to the process of removing impurities, not specifically targeting microbes. In this case, pasteurization best describes the process of reducing harmful microbes in food without completely eliminating all microorganisms.
Which statement about the fungal mycelium is correct:
- A. It consists of intertwined hyphae
- B. Part of the mycelium goes in the medium and forms the substrate mycelium
- C. Part of the mycelium stays above the medium and forms the aerial mycelium
- D. All of the above
Correct Answer: D
Rationale: Rationale:
- A: The mycelium is indeed made up of intertwined hyphae, which are the branching filaments of fungi.
- B: Part of the mycelium does grow into the medium to acquire nutrients, forming the substrate mycelium.
- C: Some parts of the mycelium remain above the medium to aid in reproduction and spore dispersal, forming the aerial mycelium.
Therefore, all statements (A, B, and C) are correct, making choice D the correct answer. The mycelium exhibits both intertwined hyphae, substrate mycelium, and aerial mycelium to facilitate different functions.
Which of the following bacterial structures has endotoxic activity?
- A. Lipopolysaccharides
- B. Lipoproteins of Braun
- C. Protein A
- D. None
Correct Answer: A
Rationale: The correct answer is A: Lipopolysaccharides. Lipopolysaccharides (LPS) are major components of the outer membrane of Gram-negative bacteria and are known to have endotoxic activity. LPS can trigger a strong immune response leading to inflammation and septic shock.
Choice B, Lipoproteins of Braun, are not known to have endotoxic activity. Choice C, Protein A, is a surface protein found in Staphylococcus aureus and is not associated with endotoxic activity. Choice D, None, is incorrect as LPS is indeed a bacterial structure with endotoxic activity.
Which of the following food media can be used for cultivation of Streptococcus pneumoniae:
- A. Blood agar
- B. MacConkey agar
- C. Peptone water
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Blood agar. Streptococcus pneumoniae is a fastidious bacterium that requires enriched media for growth. Blood agar provides the necessary nutrients and growth factors for the cultivation of S. pneumoniae, such as blood proteins and hemin. MacConkey agar (B) is selective for gram-negative bacteria and would not support the growth of S. pneumoniae. Peptone water (C) is a liquid medium that lacks the necessary nutrients for the growth of S. pneumoniae. Choice D is incorrect as blood agar is a suitable medium for cultivating S. pneumoniae.
Study of bacteriological sputum specimens stained by the Ziel-Neelsen method revealed some bright-red acid-resistant bacilli that were found in groups or singularly. When inoculated onto the nutrient media, the signs of their growth show up on the 10-15 day. These bacteria relate to the following family:
- A. Micobacterium tuberculosis
- B. Yersinia pseudotuberculosis
- C. Histoplasma dubrosii
- D. Klebsiella rhinoscleromatis
Correct Answer: A
Rationale: The correct answer is A: Mycobacterium tuberculosis.
1. Bright-red acid-resistant bacilli indicate the presence of mycolic acids in the cell wall, characteristic of Mycobacterium species.
2. Found in groups or singularly suggests the clumping nature of acid-fast bacilli.
3. Growth appearing after 10-15 days on nutrient media is consistent with the slow growth rate of Mycobacterium tuberculosis.
4. Yersinia pseudotuberculosis (B) and Klebsiella rhinoscleromatis (D) are not acid-fast bacilli and do not match the growth characteristics described.
5. Histoplasma dubrosii (C) is a fungus, not a bacterium, and does not exhibit acid-fast staining or the described growth pattern.