Nokea
Which of the following microorganisms are acid-fast?
- A. Streptococcus pyogenes
- B. Mycobacterium tuberculosis
- C. Clostridium perfringens
- D. Bacillus subtilis
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. Acid-fast bacteria have a unique cell wall component called mycolic acid, making them resistant to decolorization by acid-alcohol during staining. Mycobacterium tuberculosis is acid-fast, as it retains the stain due to its high lipid content. Streptococcus pyogenes (A), Clostridium perfringens (C), and Bacillus subtilis (D) do not possess mycolic acid in their cell walls, so they are not acid-fast.
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Which bacteria are responsible for causing the disease known as 'whooping cough'?
- A. Bordetella pertussis
- B. Haemophilus influenzae
- C. Streptococcus pneumoniae
- D. Mycobacterium tuberculosis
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. Bordetella pertussis is the bacterium responsible for causing whooping cough, also known as pertussis. It produces toxins that damage the respiratory tract, leading to severe coughing fits. Haemophilus influenzae, Streptococcus pneumoniae, and Mycobacterium tuberculosis are not associated with whooping cough. Haemophilus influenzae can cause respiratory infections but not whooping cough. Streptococcus pneumoniae is known for causing pneumonia, and Mycobacterium tuberculosis causes tuberculosis, both different from whooping cough. Therefore, the correct answer is A as it is the specific bacterium linked to the disease in question.
Viral capsomeres are composed of subunits called
- A. envelopes.
- B. protomeres.
- C. capsids.
- D. nucleoids.
Correct Answer: B
Rationale: The correct answer is B: protomeres. Viral capsomeres are the building blocks of viral capsids, which are protein coats that enclose and protect the viral genetic material. These capsomeres are made up of smaller subunits called protomeres. Envelopes (A) refer to a lipid membrane surrounding some viruses, not the subunits of capsomeres. Capsids (C) are the protein coats that capsomeres make up, not the subunits themselves. Nucleoids (D) are found in bacterial cells and refer to the region where the genetic material is located, not the subunits of viral capsomeres.
Parents with ill child came to the infectionist. They worked in one of the Asian countries for a long time. Child has eathy colored skin, loss of appetite, laxity, enlarged liver, spleen, peripheral glands. What protozoan illness can this child have?
- A. Amebiasis
- B. Balantidiasis
- C. Visceral leishmaniasis
- D. Lambliasis
Correct Answer: C
Rationale: The correct answer is C: Visceral leishmaniasis. This disease is caused by the protozoan parasite Leishmania, which is transmitted by sandfly bites. The symptoms described in the question, such as enlarged liver and spleen, peripheral gland enlargement, and eathy colored skin, are characteristic of visceral leishmaniasis. Amebiasis (choice A) typically presents with gastrointestinal symptoms, Balantidiasis (choice B) is caused by a different parasite and presents with dysentery, and Lambliasis (choice D) is caused by Giardia lamblia and presents with diarrhea.
Which of the following viruses can cause hemorrhagic cystitis in immunocompromised patients:
- A. EBV
- B. BKV
- C. HSV1
- D. JCV
Correct Answer: B
Rationale: The correct answer is B: BKV. BK virus can cause hemorrhagic cystitis in immunocompromised patients by infecting the urinary tract. It primarily affects the renal tubular epithelial cells, leading to hemorrhagic cystitis. EBV (A) causes infectious mononucleosis, HSV1 (C) causes oral and genital herpes, and JCV (D) causes progressive multifocal leukoencephalopathy, none of which are associated with hemorrhagic cystitis.
Giardiasis is a waterborne gastrointestinal disease caused by Giardia intestinalis, which is a:
- A. protozoan
- B. bacterium
- C. fungus
- D. virus
Correct Answer: A
Rationale: Step 1: Giardiasis is caused by Giardia intestinalis, which is a well-known protozoan parasite.
Step 2: Protozoans are single-celled eukaryotic organisms commonly found in water sources.
Step 3: Giardia intestinalis infects the intestine, causing symptoms like diarrhea and abdominal cramps.
Step 4: Bacteria (Choice B) are prokaryotic organisms, different from protozoans.
Step 5: Fungi (Choice C) are also eukaryotic but are not responsible for causing Giardiasis.
Step 6: Viruses (Choice D) are not cellular and cannot independently cause Giardiasis.
In summary, the correct answer is A (protozoan) because Giardia intestinalis is a protozoan parasite specifically known to cause Giardiasis, while the other choices (Bacterium, Fungus, Virus) do not match the characteristics of the