Nokea
Which molecule released by NK cells is responsible for inducing apoptosis?
- A. Perforin
- B. Granzyme
- C. Cytokines
- D. Antibodies
Correct Answer: B
Rationale: The correct answer is B: Granzyme. Granzyme is the molecule released by NK cells that induces apoptosis in target cells. It enters the target cell through perforin, which creates pores in the target cell membrane. Cytokines are signaling molecules released by various immune cells but do not directly induce apoptosis. Antibodies are produced by B cells and do not induce apoptosis. Perforin aids in the delivery of granzyme but is not responsible for inducing apoptosis itself. Therefore, Granzyme is the correct choice for inducing apoptosis by NK cells.
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Which pathway of the complement system involves properdin, Factor B, and Factor D?
- A. Classical pathway
- B. Alternative pathway
- C. Lectin pathway
- D. Terminal pathway
Correct Answer: B
Rationale: The correct answer is B: Alternative pathway. This pathway involves properdin, Factor B, and Factor D. Properdin stabilizes the C3 convertase complex formed by Factor B and Factor D, leading to the amplification of the complement cascade. The other choices are incorrect because:
A: Classical pathway is initiated by antigen-antibody complexes binding to C1q.
C: Lectin pathway is activated by lectins binding to carbohydrates on pathogen surfaces.
D: Terminal pathway involves the formation of the membrane attack complex.
What is a characteristic feature of Goodpasture's syndrome?
- A. Granuloma formation
- B. Pulmonary hemorrhage and glomerulonephritis
- C. Contact dermatitis
- D. Bronchoconstriction and vasodilation
Correct Answer: B
Rationale: The correct answer is B: Pulmonary hemorrhage and glomerulonephritis. Goodpasture's syndrome is an autoimmune disease characterized by the presence of anti-glomerular basement membrane antibodies, leading to damage in the kidneys (glomerulonephritis) and lungs (pulmonary hemorrhage). Granuloma formation (A), contact dermatitis (C), and bronchoconstriction and vasodilation (D) are not characteristic features of Goodpasture's syndrome. Granulomas are more commonly seen in conditions like sarcoidosis, contact dermatitis is an inflammatory skin condition, and bronchoconstriction and vasodilation are features of allergic reactions or asthma, not typically seen in Goodpasture's syndrome.
The HIV protein that allows fusion of the viral envelope with the cell plasma membrane is
- A. gp120
- B. gp41
- C. gp160
- D. CXCR4
Correct Answer: B
Rationale: The correct answer is B: gp41. Gp41 is responsible for the fusion of the viral envelope with the cell plasma membrane by undergoing conformational changes that allow the viral and cellular membranes to merge. Gp120 attaches to the host cell receptor (CD4), facilitating the binding of the virus to the host cell. Gp160 is the precursor protein that is cleaved into gp120 and gp41 during viral maturation. CXCR4 is a cellular co-receptor used by some strains of HIV to enter host cells but is not directly involved in the fusion process.
Which one of the following processes emerged earliest during the course of evolution?
- A. Antigen presentation
- B. Antibody production
- C. Phagocytosis
- D. Thymic education
Correct Answer: C
Rationale: The correct answer is C: Phagocytosis. Phagocytosis is a fundamental process that emerged early in evolution for cellular organisms to engulf and digest particles. This process is essential for basic survival and defense mechanisms.
A: Antigen presentation and B: Antibody production are more advanced immune responses that occur in higher organisms and require a complex immune system.
D: Thymic education is a process specific to vertebrates involving the maturation and selection of T cells, which is a more evolved mechanism compared to phagocytosis.
Therefore, phagocytosis is the earliest process among the options listed as it is essential for basic cellular survival and predates the development of advanced immune responses.
A patient has come to the ambulatory care clinic with a sprain. The nurse correctly differentiates a grade 2 sprain from a grade 3 sprain with the assessment of which finding?
- A. Pain
- B. Swelling
- C. Bleeding into the joint
- D. Minor loss of function
Correct Answer: D
Rationale: The correct answer is D: Minor loss of function. A grade 2 sprain involves partial tearing of the ligament, leading to moderate pain, swelling, and a significant loss of function. In contrast, a grade 3 sprain involves complete tearing of the ligament, resulting in severe pain, significant swelling, and major loss of function. By assessing for minor loss of function, the nurse can differentiate between the two grades of sprains. Choices A, B, and C are incorrect because they do not specifically differentiate between a grade 2 and grade 3 sprain based on the level of functional impairment.