Nokea
Which of the following correctly explains an epitope?
- A. Region of antibody that binds with antigen
- B. Region of antigen that elicit secretion of specific antibody
- C. Heavy chain of an antibody
- D. V-region of the light chain of antibody
Correct Answer: B
Rationale: Explanation:
An epitope is a specific region on an antigen that elicits the immune response and triggers the production of a specific antibody. Therefore, choice B is correct as it accurately defines an epitope. Choices A, C, and D are incorrect because they do not accurately describe what an epitope is. Choice A refers to the paratope, the region of the antibody that binds to the epitope. Choice C refers to a component of the antibody structure, and choice D refers to a specific region of the antibody structure.
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What is hyperkalemia frequently associated with?
- A. Hypoglycemia
- B. Metabolic acidosis
- C. Respiratory alkalosis
- D. Decreased urine potassium levels
Correct Answer: B
Rationale: Metabolic acidosis increases hydrogen ion exchange for potassium in cells, releasing potassium into the bloodstream and causing hyperkalemia.
Where do T cells mature?
- A. Bone marrow
- B. Thymus
- C. Spleen
- D. Lymph nodes
Correct Answer: B
Rationale: The correct answer is B: Thymus. T cells mature in the thymus, where they undergo selection and maturation processes essential for their function in the immune system. The thymus provides a specialized environment for T cell development, including positive and negative selection to ensure self-tolerance and functional T cell repertoire.
A: Bone marrow is incorrect because it is the site of B cell maturation, not T cells.
C: Spleen is incorrect as it acts as a secondary lymphoid organ for immune response but not the site of T cell maturation.
D: Lymph nodes are incorrect as they are important for immune surveillance and activation but not the primary site for T cell maturation.
Virulence factors can be transferred from pathogenic to non-pathogenic bacterial strains that are part of the normal flora. An example of a commensal bacterial species that has turned into a pathogenic strain is:
- A. E. coli 0157:H7
- B. M. tuberculosis
- C. Group A S. pyogenes
- D. All opportunistic bacterial species
Correct Answer: A
Rationale: The correct answer is A: E. coli 0157:H7. This strain of E. coli has acquired virulence factors that allow it to cause severe illness in humans, such as bloody diarrhea and kidney failure. The transformation of E. coli from a commensal to a pathogenic strain is well-documented. In contrast, choices B and C involve species that are inherently pathogenic and not commensal. Choice D is too broad and includes a wide range of bacterial species that do not necessarily originate from the normal flora. Therefore, E. coli 0157:H7 is the best example of a commensal bacterium that has turned pathogenic due to the acquisition of virulence factors.
Which of the following is not considered a virulence factor?
- A. Flagella
- B. Effector proteins manipulating host actin cytoskeleton
- C. Toxins
- D. Peptidoglycan
Correct Answer: D
Rationale: The correct answer is D: Peptidoglycan. Peptidoglycan is a structural component of bacterial cell walls and does not directly contribute to the pathogenicity or virulence of the bacterium. Flagella aid in motility and colonization, effector proteins manipulate host cells, and toxins damage host tissues, all of which are virulence factors. Peptidoglycan is essential for maintaining cell shape and integrity but does not directly enhance the ability of the bacteria to cause disease.
The patient is transferring from another facility with the description of a sore on her sacrum that is deep enough to see the muscle. What stage of pressure ulcer does the nurse expect to see on admission?
- A. Stage I
- B. Stage II
- C. Stage III
- D. Stage IV
Correct Answer: D
Rationale: Stage IV pressure ulcers involve full-thickness tissue loss, exposing muscle, tendon, or bone.