Nokea
After the transfer of the F plasmid from the donor to the recipient cell..
- A. It is not possible to predict the outcome
- B. The donor cells become F
- C. The two cells become F
- D. The two cells become F+
Correct Answer: D
Rationale: After the transfer of the F plasmid from the donor to the recipient cell, the correct answer is D. This is because the F plasmid carries genes for conjugation, allowing the recipient cell to become F+ (containing the F plasmid). The donor cell remains F. Choice A is incorrect as the outcome can be predicted based on the transfer of the F plasmid. Choice B is incorrect because the donor cell does not become F after transferring the F plasmid. Choice C is incorrect as only the recipient cell becomes F+, not both cells.
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The phagocytosis is:
- A. Killing of bacterial cells with bactericidal antibiotics
- B. Blocking of key bacterial enzymes
- C. Active engulf and destruction of microorganisms by some host cells
- D. There is no correct answer
Correct Answer: C
Rationale: The correct answer is C because phagocytosis refers to the process where certain host cells engulf and destroy microorganisms. This is an essential mechanism of the immune system to eliminate pathogens. Choice A is incorrect because phagocytosis does not involve the use of antibiotics. Choice B is incorrect as it describes a different mechanism of action against bacteria. Choice D is incorrect because phagocytosis is a well-established biological process.
The enzyme used by bacteria to break down hydrogen peroxide is:
- A. Amylase
- B. Catalase
- C. Lipase
- D. Protease
Correct Answer: B
Rationale: The correct answer is B: Catalase. Catalase is the enzyme responsible for breaking down hydrogen peroxide into water and oxygen. This process helps protect the bacteria from oxidative damage caused by hydrogen peroxide. Amylase (A), Lipase (C), and Protease (D) are enzymes that are not involved in breaking down hydrogen peroxide. Amylase is involved in breaking down starch, Lipase breaks down lipids, and Protease breaks down proteins. Therefore, they are not the correct enzymes for the given question.
An 18-year-old patient has enlarged inguinal lymph nodes, they are painless, thickened on palpation. In the area of genital mucous membrane there is a small-sized ulcer with thickened edges and "laquer"bottom of greyish colour. What is the most probable diagnosis?
- A. Syphilis
- B. Tuberculosis
- C. Lepra
- D. Trophic ulcer
Correct Answer: A
Rationale: The correct answer is A: Syphilis. The presentation of painless inguinal lymph nodes, along with a small-sized ulcer with thickened edges and a "laquer" bottom of greyish color on the genital mucous membrane, is classic for primary syphilis. The painless nature of the lymph nodes and the specific characteristics of the ulcer are key features of syphilitic infection. Primary syphilis is caused by the bacterium Treponema pallidum and typically presents with a single, painless ulcer known as a chancre. It is important to consider syphilis in the differential diagnosis of genital ulcers.
Summary of other choices:
B: Tuberculosis - Unlikely, as tuberculosis typically presents with pulmonary symptoms and does not cause genital ulcers.
C: Lepra - Unlikely, as leprosy does not typically present with painless inguinal lymph nodes and the specific ulcer characteristics described.
D: Trophic ulcer - Unlikely
A patient has food poisoning. Laboratory analysis revealed a culture of anaerobic gram-positive spore-forming bacteria. What is the most likely kind of the isolated causative agent?
- A. C. perfringens
- B. Proteus vulgaris
- C. P. mirabilis
- D. Vibrio parahemolyticus
Correct Answer: A
Rationale: The correct answer is A: C. perfringens. This is because Clostridium perfringens is a gram-positive, anaerobic, spore-forming bacterium commonly associated with food poisoning. It produces toxins that cause gastrointestinal symptoms. Proteus vulgaris (B) and P. mirabilis (C) are gram-negative bacteria not typically associated with food poisoning. Vibrio parahemolyticus (D) is a gram-negative bacterium causing seafood-related gastroenteritis, not spore-forming or anaerobic.
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.