ATI RN
microbiology chapter 13 test bank Questions
Question 1 of 5
DNA replication occurs in which phase of the cell cycle?
Correct Answer: D
Rationale: The correct answer is D: S phase. During the S phase of the cell cycle, DNA replication takes place to ensure each daughter cell receives a complete set of genetic material. This phase is characterized by the synthesis of new DNA strands. In contrast, choices A, B, and C (G phase, Prophase, Metaphase) are not associated with DNA replication. The G phase is a period of cell growth, Prophase is the initial stage of mitosis, and Metaphase is when chromosomes align. Therefore, the S phase is the specific stage where DNA replication occurs, making it the correct answer.
Question 2 of 5
Which of the following bacteria should be handled in a Biosafety Level 2 facility?
Correct Answer: C
Rationale: The correct answer is C: Salmonella. This bacterium should be handled in a Biosafety Level 2 facility due to its potential to cause disease in humans. Salmonella is a pathogenic bacterium that can cause foodborne illnesses and infections. Handling it in a Biosafety Level 2 facility ensures proper containment and protection of personnel. A: Micrococcus luteus and B: Bacillus subtilis are common environmental bacteria that do not pose significant risks to human health, so they can be safely handled in lower biosafety levels. D: Staphylococcus epidermidis is a common skin commensal bacterium that is generally not considered highly pathogenic, so it does not require Biosafety Level 2 containment.
Question 3 of 5
A 10 year old child was subjected to Mantoux test (with tuberculin). 48 hours later a papule up to 8 mm in diameter appeared on the site of tuberculin injection. What type of hyperesponsiveness reaction has developed after tuberculin injection?
Correct Answer: A
Rationale: The correct answer is A: Hyperresponsiveness reaction type IV. This type of reaction, also known as delayed-type hypersensitivity, is characterized by the activation of T lymphocytes and macrophages, leading to inflammation at the site of antigen exposure. In the case of the Mantoux test, the appearance of a papule 48 hours later indicates a delayed hypersensitivity reaction mediated by T cells. Choice B: Reaction of Arthus phenomenon type is incorrect as this type of reaction involves immune complexes forming in the blood vessels leading to tissue damage, which is not the mechanism seen in the Mantoux test reaction. Choice C: Reaction of serum sickness type is incorrect as this type of reaction involves the formation of immune complexes in the blood leading to systemic symptoms like fever, rash, and joint pain, which is not typically seen in the Mantoux test reaction. Choice D: Atopic reaction is incorrect as atopic reactions involve IgE antibodies and mast cell degranulation, which are not the mechanisms
Question 4 of 5
During the skill-building session in microbiology the students need to stain the prepared and fixed sputum smears obtained from a tuberculosis patient. What staining technique should be used in this case?
Correct Answer: C
Rationale: The correct staining technique for staining sputum smears from a tuberculosis patient is Ziehl-Neelsen staining. This technique uses a carbol fuchsin stain that specifically stains acid-fast organisms like Mycobacterium tuberculosis. The steps involved include staining with carbol fuchsin, decolorizing with acid-alcohol, counterstaining with methylene blue, and then examining under a microscope. This staining method is crucial for detecting the acid-fast bacilli characteristic of tuberculosis. Explanation for incorrect choices: A: Gram staining is used to differentiate bacteria into Gram-positive and Gram-negative, not suitable for acid-fast organisms like Mycobacterium tuberculosis. B: Giemsa staining is used for detecting parasites and certain types of white blood cells, not specific for acid-fast bacteria. D: Burry staining is not a recognized staining technique in microbiology for staining acid-fast organisms.
Question 5 of 5
On a certain territory mass death of rodents was registered. It was suspected that their death might have been caused by plague. What serological reaction should be applied for quick identification of antigen of the causative agent of this epizooty?
Correct Answer: B
Rationale: The correct answer is B: Agglutination. During a suspected plague outbreak, agglutination testing is used to quickly identify the antigen of the causative agent. In this test, specific antibodies are added to a sample containing the suspected antigen. If the antigen is present, it will clump together (agglutinate) with the antibodies, indicating a positive result. This method is rapid and efficient for identifying the presence of the plague-causing agent. Choice A: Precipitation involves the formation of a visible precipitate when antigen and antibody react, but it is not as quick or specific as agglutination for identifying the antigen in this scenario. Choice C: Passive hemagglutination is a variation of agglutination that uses red blood cells as carriers for antigens or antibodies. While it can be useful in certain situations, it is not typically the first choice for rapid identification of plague antigen. Choice D: Complement binding is a different type of