Nokea
The enzyme that breaks down the peptidoglycan in bacterial cell walls is:
- A. Lysozyme
- B. Amylase
- C. Protease
- D. Lipase
Correct Answer: A
Rationale: The correct answer is A: Lysozyme. Lysozyme is an enzyme that targets and breaks down the peptidoglycan in bacterial cell walls by cleaving the glycosidic bonds between the sugar components. This action weakens the cell wall, leading to bacterial cell lysis. Amylase (B) breaks down starch, not peptidoglycan. Protease (C) breaks down proteins, not peptidoglycan. Lipase (D) breaks down lipids, not peptidoglycan. Therefore, Lysozyme is the correct enzyme for breaking down peptidoglycan in bacterial cell walls.
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Which bacteria is known for causing the disease cholera?
- A. Shigella dysenteriae
- B. Vibrio cholerae
- C. Salmonella enterica
- D. Clostridium perfringens
Correct Answer: B
Rationale: The correct answer is B: Vibrio cholerae. Cholera is caused by Vibrio cholerae, a gram-negative bacterium that produces a toxin leading to severe watery diarrhea. Shigella dysenteriae causes dysentery, not cholera. Salmonella enterica causes salmonellosis, not cholera. Clostridium perfringens is associated with food poisoning, not cholera. In summary, Vibrio cholerae is the correct answer because it is the specific bacterium known to cause cholera, while the other choices are associated with different diseases.
The only way to get energy in haematrophic bacteria is:
- A. Heat production
- B. Biological oxidation
- C. In biosynthetic reactions
- D. Cultivation in culture media
Correct Answer: B
Rationale: The correct answer is B: Biological oxidation. Haematrophic bacteria obtain energy through biological oxidation, where they break down organic compounds to generate ATP for cellular processes. This process involves the transfer of electrons from the substrate to an electron transport chain to produce energy. Heat production (A) is a byproduct of metabolism, not the primary way to obtain energy. In biosynthetic reactions (C), energy is utilized rather than generated. Cultivation in culture media (D) is a method of growing bacteria but does not directly provide energy. Therefore, the correct answer is B as it aligns with the metabolic process of haematrophic bacteria.
Specimen of a patient's sputum was stained with the following dyes and reagents: Ziehl's solution, methylene blue solution, 5% solutoin of sulfuric acid. What staining method was applied?
- A. Ziehl-Neelsen
- B. Burri's
- C. Gram's
- D. Peshkov's
Correct Answer: A
Rationale: The correct answer is A: Ziehl-Neelsen staining method was applied.
1. Ziehl's solution is used as a primary stain in Ziehl-Neelsen staining for acid-fast organisms like Mycobacterium tuberculosis.
2. Sulfuric acid is used as a decolorizer to remove excess stain.
3. Methylene blue is not part of the Ziehl-Neelsen staining method.
4. Burri's, Gram's, and Peshkov's staining methods are not used for acid-fast staining.
A worker of a cattle farm consulted a surgeon about fever up to 40oC, headache, weakness. Objective examination of his back revealed hyperaemia and a dark red infiltration up to 5 cm in diameter with black bottom in the center and some pustules. What disease are these presentations typical for?
- A. Anthrax
- B. Plaque
- C. Tularemia
- D. Furuncle
Correct Answer: A
Rationale: The correct answer is A: Anthrax. The symptoms of fever, headache, weakness, and the skin lesion described (hyperemic with a dark red infiltration, black center, and pustules) are characteristic of cutaneous anthrax. The black center is known as an eschar. Anthrax is caused by the bacterium Bacillus anthracis, commonly found in cattle. Plague (choice B) typically presents with swollen lymph nodes (buboes) and is caused by Yersinia pestis. Tularemia (choice C) presents with fever, ulcer at the site of infection, and lymphadenopathy, caused by Francisella tularensis. Furuncle (choice D) is a localized skin infection typically caused by Staphylococcus aureus, presenting as a red, swollen, and painful bump.
The bacteria that cause Lyme disease is:
- A. Treponema pallidum
- B. Borrelia burgdorferi
- C. Leptospira interrogans
- D. Rickettsia rickettsii
Correct Answer: B
Rationale: The correct answer is B: Borrelia burgdorferi. Borrelia burgdorferi is the bacteria responsible for causing Lyme disease. It is transmitted to humans through the bite of infected black-legged ticks. Treponema pallidum causes syphilis, Leptospira interrogans causes leptospirosis, and Rickettsia rickettsii causes Rocky Mountain spotted fever. Borrelia burgdorferi is specifically associated with Lyme disease due to its transmission through tick bites and the characteristic symptoms it causes.