Nokea
With regard to NADPH oxidase, which of the following statements in not correct?
- A. It is the enzyme involved in the respiratory burst that follows the engagement of phagocytic receptors
- B. Individuals with mutations of NADPH oxidase subunits suffer repeated infections because of defective killing of phagocytosed pathogens
- C. It is constitutively expressed as a complex of 5 subunits in unstimulated cells
- D. It controls the formation of reactive oxygen species
Correct Answer: C
Rationale: The correct answer is C because NADPH oxidase is not constitutively expressed as a complex of 5 subunits in unstimulated cells. Instead, it is assembled and activated upon stimulation, such as during the respiratory burst following phagocytosis. Choice A is correct as NADPH oxidase is indeed involved in the respiratory burst. Choice B is correct as mutations in NADPH oxidase subunits lead to impaired pathogen killing and recurrent infections. Choice D is correct as NADPH oxidase controls the production of reactive oxygen species.
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Which characteristics are seen with acute transplant rejection (select all that apply)?
- A. Treatment is supportive
- B. Only occurs with transplanted kidneys
- C. Organ must be removed when it occurs
- D. The recipient’s T cytotoxic lymphocytes attack the foreign organ
Correct Answer: D
Rationale: Acute transplant rejection involves the recipient's T cytotoxic lymphocytes attacking the transplanted organ, requiring immunosuppressive therapy.
Which of the following sentences concerned with lymph node structure is incorrect?
- A. naïve B lymphocytes are found in the cortex
- B. naïve T lymphocytes are found in the paracortex
- C. naïve lymphocytes enter the lymph node through the efferent lymphatic vessel
- D. Antigens can enter the lymph node through afferent lymphatic vessels
Correct Answer: C
Rationale: Rationale:
C is incorrect because naïve lymphocytes actually enter the lymph node through the afferent lymphatic vessel, not the efferent. A carries lymphocytes into the lymph node, and D is true since antigens enter through afferent vessels. B is correct, as naïve T cells are found in the paracortex.
What is the medical term for an abnormal accumulation of blood in a tissue or organ?
- A. Hematoma
- B. Thrombosis
- C. Embolus
- D. Hemorrhage
Correct Answer: A
Rationale: The correct answer is A: Hematoma. A hematoma is an abnormal collection of blood within tissues. This occurs due to broken blood vessels and can lead to swelling and localized pain. Thrombosis (B) is the formation of a blood clot within a blood vessel, not an accumulation of blood in tissue. An embolus (C) is a blood clot that travels through the bloodstream and gets lodged in a blood vessel. Hemorrhage (D) refers to the excessive bleeding from blood vessels. In this case, the most appropriate term for an abnormal accumulation of blood in a tissue is hematoma.
If you were to observe the activity of methylated DNA, you would expect it to
- A. be unwinding in preparation for protein synthesis.
- B. be replicating nearly continuously.
- C. have turned off or slowed down the process of transcription.
- D. induce protein synthesis by not allowing repressors to bind to it.
Correct Answer: C
Rationale: The correct answer is C because methylation of DNA typically results in the inhibition or slowing down of transcription. Methylated DNA attracts proteins that bind to it, preventing transcription factors from accessing the DNA and initiating transcription. This interference with the transcription process leads to gene silencing or reduced gene expression.
A: DNA unwinding in preparation for protein synthesis is unrelated to DNA methylation.
B: Continuous replication is not a typical consequence of DNA methylation.
D: Methylation does not directly induce protein synthesis but rather affects transcription by influencing gene expression.
The nurse is preparing an injection for an individual who requires passive immunity. In which situation would passive immunity be indicated?
- A. For permanent immunity against a disease
- B. To overcome an allergic reaction that is relatively mild
- C. To have ready-made antibodies after an exposure to pathogens
- D. As a booster dose to stimulate the production of specific antibodies
Correct Answer: C
Rationale: Passive immunity is indicated when an individual needs immediate protection with ready-made antibodies after exposure to pathogens. This is the correct answer (C) as it provides immediate defense without waiting for the body to produce its antibodies. Choice A is incorrect because passive immunity is temporary, not permanent. Choice B is incorrect as it addresses treating allergic reactions, not providing immunity. Choice D is incorrect as a booster dose stimulates the body to produce its antibodies, not providing ready-made antibodies.