ATI RN
mcgraw hill microbiology test bank Questions
Question 1 of 5
The nucleocapsid of viruses consists of
Correct Answer: B
Rationale: The correct answer is B because the nucleocapsid of viruses is composed of the genome (genetic material) and the capsid (protein coat). The genome contains the viral genetic information, while the capsid protects the genome and helps in viral attachment and entry into host cells. Choice A is incorrect because the envelope is not part of the nucleocapsid but surrounds the capsid in some viruses. Choice C is incorrect as spikes are surface proteins on the viral envelope, not part of the nucleocapsid. Choice D is also incorrect because the envelope is external to the capsid and genome in many viruses.
Question 2 of 5
Microscopic examination of a patient's duodenal contents revealed protozoa with two nuclei, four flagella, and a ventral adhesive disc. What is the likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Giardia lamblia. This protozoan matches the description of the causative agent because it has two nuclei, four flagella, and a ventral adhesive disc. Giardia lamblia is commonly found in the duodenum and causes giardiasis. The other choices can be eliminated because Leishmania donovani causes visceral leishmaniasis, not the described symptoms. Entamoeba coli is a non-pathogenic amoeba found in the large intestine. Trypanosoma gambiense causes African trypanosomiasis and is transmitted by the tsetse fly, not matching the described characteristics.
Question 3 of 5
The causative agent of syphilis is:
Correct Answer: B
Rationale: The correct answer is B: Treponema pallidum. 1. Treponema pallidum is a spirochete bacterium known to cause syphilis. 2. Borrelia burgdorferi causes Lyme disease, not syphilis. 3. Leptospira interrogans causes leptospirosis, not syphilis. 4. Rickettsia rickettsii causes Rocky Mountain spotted fever, not syphilis. Therefore, Treponema pallidum is the causative agent of syphilis, making it the correct answer.
Question 4 of 5
Which of the following microorganisms are acid-fast?
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.
Question 5 of 5
The bacteria that cause Lyme disease is:
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.