ATI RN
microbiology chapter 12 test bank Questions
Question 1 of 9
In which phase of mitosis do the chromatids separate?
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.
Question 2 of 9
Which of the following lack nucleic acids?
Correct Answer: C
Rationale: The correct answer is C: Prions. Prions are infectious proteins that lack nucleic acids, such as DNA or RNA, which are essential components of all other living organisms, including Archaea, Bacteria, and Viruses. Prions are unique in their ability to cause protein misfolding and aggregation in the brain, leading to various neurodegenerative diseases. The other choices (A: Archaea, B: Viruses, D: Bacteria) all contain nucleic acids in the form of DNA or RNA, making them distinct from prions. Therefore, C is the correct answer in this case.
Question 3 of 9
The cytopathic effect caused by viruses of family paramyxoviridae looks like:
Correct Answer: B
Rationale: Rationale: The correct answer is B. Viruses of the family Paramyxoviridae cause the formation of giant multinucleated cells called syncytia. This occurs when infected cells fuse together, resulting in large, multinucleated structures. This is a characteristic cytopathic effect of paramyxoviruses. Summary: A: Fine grained degeneration is not typically seen in paramyxovirus infections. C: Large cell degeneration with grape clustering of cells is not a typical cytopathic effect of paramyxoviruses. D: Paramyxoviruses do provoke a cytopathic effect, so this statement is incorrect.
Question 4 of 9
A Gram-stained sputum smear revealed Gram-positive rods in chains with central spores. The patient presented with severe pneumonia. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. The presence of Gram-positive rods in chains with central spores on the Gram stain indicates Bacillus anthracis. This bacterium is known to cause severe pneumonia. Clostridium tetani does not typically cause pneumonia but rather tetanus. Streptococcus pneumoniae is a Gram-positive cocci, not rods. Klebsiella pneumoniae is a Gram-negative bacterium commonly associated with pneumonia, but it does not form central spores.
Question 5 of 9
Micellar growth
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.
Question 6 of 9
The term bacilli is related to:
Correct Answer: B
Rationale: The term bacilli refers to rod-shaped bacteria, typically found in the Gram-positive group. Spore-forming bacteria, such as Bacillus and Clostridium, are characterized by their rod shape. Choice A is incorrect as the color in Gram staining does not define bacilli. Choice C is incorrect as peptidoglycan content does not determine the classification of bacilli. Choice D is incorrect as bacilli do have a specific characteristic. Therefore, the correct answer is B due to the shape and characteristic of spore-forming bacteria.
Question 7 of 9
Which toxin is specific for ETEC:
Correct Answer: D
Rationale: The correct answer is D: LT enterotoxin. This toxin is specific for Enterotoxigenic E. coli (ETEC) and is responsible for causing diarrhea by increasing cyclic AMP levels in intestinal cells. TSST-1 (choice A) is produced by Staphylococcus aureus, not ETEC. Shiga-like toxin (choice B) is produced by Shigella and EHEC, not ETEC. Erythrogenic toxin (choice C) is produced by Streptococcus pyogenes, not ETEC. Therefore, the LT enterotoxin is the specific toxin associated with ETEC.
Question 8 of 9
In the cytoplasm of some bacteria there are substances in the form of granules. They are:
Correct Answer: D
Rationale: The correct answer is D. Cytoplasmic inclusions in bacteria refer to substances like granules. These granules can be excess products of metabolism or reserve substances stored for future use. Therefore, all of the choices are correct as cytoplasmic inclusions can be any of these substances. A is correct as it directly refers to cytoplasmic inclusions. B is correct as some granules can be excess metabolic products. C is correct as certain granules can serve as reserve substances. Therefore, the correct answer is D, as it encompasses all the possible types of substances found as cytoplasmic inclusions in bacteria.
Question 9 of 9
Examination of duodenal contents revealed some pyriform protozoa with twin nuclei and four pairs of flagella. There were two supporting filaments between the nuclei and a suctorial disc on the ventral side. What representative of protozoa was revealed in this patient?
Correct Answer: D
Rationale: The correct answer is D: Intestinal trichomonad. This protozoan matches the description provided, with pyriform shape, twin nuclei, four pairs of flagella, supporting filaments, and a suctorial disc. Lamblia (A) lacks flagella and supporting filaments. Toxoplasma (B) is an intracellular parasite with different morphology. Leishmania (C) belongs to a different class with no flagella or supporting filaments. In summary, the unique combination of features described in the question points to an intestinal trichomonad, making it the correct answer.