microbiology an introduction test bank

Correct Answer: B

Rationale: The correct answer is B: Gram-negative bacteria. Gram-negative bacteria have an outer membrane containing lipopolysaccharides (LPS). In the Gram staining technique, these bacteria appear pink/red due to the thin peptidoglycan layer, which allows the crystal violet stain to be washed out, revealing the safranin counterstain. Gram-positive bacteria (choice A) have a thick peptidoglycan layer but lack an outer membrane with LPS. Choice C is incorrect since only Gram-negative bacteria possess LPS in their outer membrane. Choice D is incorrect as all bacteria can be classified as either Gram-positive or Gram-negative based on their cell wall structure.

Correct Answer: C

Rationale: The correct answer is C: Identification. Bacteria are studied by identification to determine their specific characteristics and differentiate between different species. Taxonomy (A) is the science of classification, not specific to bacteria. Classification (B) is the process of grouping organisms based on shared characteristics, not specific to bacteria. Nomenclature (D) is the naming system for organisms, not the primary method for studying bacteria. Therefore, identification (C) is the correct choice for studying bacteria.

Correct Answer: D

Rationale: The most probable diagnosis is D: Tularemia. Tularemia is a bacterial infection caused by Francisella tularensis. The symptoms described align with tularemia, such as pain in axillary area, fever, shaky gait, coated tongue, frequent pulse, painful lymphatic nodules, and erythematous skin over nodules. The key features pointing towards tularemia are the presence of lymphadenitis in the axillary area and the erythematous, glistering skin over the nodules, which are characteristic of ulceroglandular tularemia. Bubonic plague (A) presents with painful, swollen lymph nodes called buboes but typically lacks the erythematous skin findings. Acute purulent lymphadenitis (B) usually presents with pus-filled lymph nodes but does not typically cause shaky gait or coated tongue. Lymphogranulomatosis (C) is a term for Hodgkin's lymphoma, which does not

Correct Answer: C

Rationale: The correct answer is C: urethra. Resident microflora refers to the normal, beneficial bacteria that inhabit a specific area of the body without causing harm. The urethra is one of the locations where resident microflora are commonly found. These bacteria play a vital role in maintaining a healthy balance and preventing harmful pathogens from colonizing the urethra. Blood (A), lung (B), and cerebro-spinal fluid (D) are not typical locations for resident microflora as these areas are usually sterile or have very limited microbial presence to prevent infections.

Correct Answer: A

Rationale: The correct answer is A: Rotavirus. Rotavirus is a member of the Reoviridae family known for causing diarrhea in infants. It infects the lining of the small intestine, leading to symptoms like vomiting and watery diarrhea. Rationale: 1. Rotavirus is specifically known for causing diarrhea in infants. 2. Reoviruses are a family of viruses to which rotavirus belongs. 3. Congovirus (B), Hepadnavirus (C), and Picornavirus (D) do not belong to the Reoviridae family and are not associated with causing diarrhea in infants. In summary, choice A is correct as it aligns with the characteristics of the given family of viruses and their associated symptoms, while choices B, C, and D are incorrect as they do not fit these criteria.