Nokea
Which of the following bacteria produce toxins that can cause severe gastrointestinal illness?
- A. Vibrio cholerae
- B. Clostridium difficile
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above," because all three bacteria listed (Vibrio cholerae, Clostridium difficile, Escherichia coli) produce toxins that can cause severe gastrointestinal illness. Vibrio cholerae produces cholera toxin leading to severe diarrhea. Clostridium difficile produces toxins causing antibiotic-associated diarrhea. Escherichia coli can produce toxins such as Shiga toxin causing severe gastrointestinal symptoms. Therefore, all the options listed are correct in producing toxins that can result in severe gastrointestinal illness.
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In which phase of mitosis do the chromatids separate?
- A. Prophase
- B. Metaphase
- C. Anaphase
- D. Telophase
Correct Answer: C
Rationale: In anaphase, sister chromatids separate and move towards opposite poles of the cell. This is facilitated by the shortening of microtubules attached to the centromeres. Prophase is the phase where chromosomes condense and the nuclear envelope breaks down. Metaphase is when chromosomes align at the metaphase plate. Telophase is when the nuclear envelope reforms and chromosomes decondense. Therefore, anaphase is the correct phase for chromatid separation.
Bacillary dysentery is also called:
- A. salmonellosis
- B. shigellosis
- C. typhoid fever
- D. campylobacteriosis
Correct Answer: B
Rationale: Bacillary dysentery is caused by the bacterium Shigella, hence it is also known as shigellosis. Shigella is the primary pathogen responsible for this infectious disease, leading to severe diarrhea with blood and mucus. Salmonellosis (A) is caused by Salmonella bacteria, not Shigella. Typhoid fever (C) is caused by Salmonella typhi, not Shigella. Campylobacteriosis (D) is caused by Campylobacter bacteria, not Shigella. Therefore, the correct answer is B because Shigella is the specific bacterium associated with bacillary dysentery.
Artificial active immunity occurs after a vaccination: injecting or taking antigens by mouth. Takes time for T and B cells to be activated but gives relatively long lasting:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on the given situation
- D. None of the above
Correct Answer: A
Rationale: 1. Vaccination introduces antigens to stimulate immune response.
2. T and B cells are activated to produce memory cells for long-lasting protection.
3. Active immunity develops over time post-vaccination.
4. Choice A is correct as it accurately describes the process and outcomes.
5. Choice B is incorrect as it contradicts the process of active immunity.
6. Choice C is incorrect as the process of active immunity is consistent regardless of the situation.
7. Therefore, the correct answer is A as it aligns with the mechanism and characteristics of artificial active immunity.
Micellar growth
- A. is observed in bacterial cells
- B. includes a parent and daughter cell which have different sizes
- C. is inherent in viruses and rickettsia
- D. represents apical prolongation of the hyphae in the fungus
Correct Answer: D
Rationale: Step 1: Micellar growth refers to the apical prolongation of hyphae in fungi.
Step 2: Fungi have a unique growth structure with hyphae extending at the tips.
Step 3: This growth pattern allows fungi to expand and access nutrients.
Step 4: Bacterial cells (A) do not exhibit micellar growth.
Step 5: Parent and daughter cells in division have similar sizes, not different (B).
Step 6: Viruses and rickettsia (C) do not display micellar growth.
On the 8th day since the patient was inoculated with antitetanic serum because of dirty wound of his foot he has developed rising temperature up to 380% , pains in the joints, rash and itch. The blood tests revealed leukopenia and thrombocytopenia. Allergic reaction of what type has developed in this case?
- A. Anaphylactic
- B. Cytotoxic
- C. Delayed type of hypersensitivity
- D. Immunocomplex
Correct Answer: D
Rationale: The correct answer is D: Immunocomplex. In this case, the patient's symptoms of fever, joint pains, rash, and itch along with leukopenia and thrombocytopenia indicate a serum sickness reaction. This is a type III hypersensitivity reaction where antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage. The symptoms typically occur 1-2 weeks after exposure to the antigen. Anaphylactic reaction (choice A) is immediate and involves IgE antibodies. Cytotoxic reaction (choice B) involves destruction of cells by antibodies. Delayed hypersensitivity (choice C) usually takes 48-72 hours to develop and involves T-cells. Therefore, the correct answer is D as it aligns with the symptoms and timeline of a type III hypersensitivity reaction.