Nokea
Which TLR is primarily responsible for recognizing lipopolysaccharide (LPS)?
- A. TLR2
- B. TLR4
- C. TLR5
- D. TLR9
Correct Answer: B
Rationale: The correct answer is B: TLR4. TLR4 is primarily responsible for recognizing lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria. It forms a complex with MD-2 and CD14 to trigger downstream signaling pathways. TLR2 recognizes other microbial components such as lipoproteins. TLR5 recognizes flagellin, a component of bacterial flagella. TLR9 recognizes unmethylated CpG DNA motifs. Therefore, TLR4 is specifically involved in detecting LPS, making it the correct answer in this scenario.
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Tropism is a phenomenon by which
- A. plants response to stimulation
- B. reducing lateral branching
- C. Affected by the length of the day and night
- D. All above
Correct Answer: A
Rationale: The correct answer is A: plants response to stimulation. Tropism refers to the growth or movement of an organism in response to a stimulus. Plants exhibit tropisms such as phototropism (response to light) and geotropism (response to gravity). This choice accurately defines the phenomenon.
Choice B is incorrect because reducing lateral branching is not a defining characteristic of tropism.
Choice C is incorrect because the length of day and night does not directly relate to tropism.
Choice D is incorrect because not all options listed are characteristics of tropism.
Which complement pathway is triggered by mannose-binding lectin (MBL)?
- A. Alternative pathway
- B. Classical pathway
- C. Lectin pathway
- D. Terminal pathway
Correct Answer: C
Rationale: The correct answer is C, Lectin pathway. MBL recognizes pathogen-associated molecular patterns containing mannose, initiating the lectin pathway. MBL binds to mannose on microbial surfaces, activating MBL-associated serine proteases, leading to the formation of the C3 convertase. This triggers the rest of the complement cascade.
A: Alternative pathway is triggered by spontaneous hydrolysis of C3, not by MBL.
B: Classical pathway is activated by antigen-antibody complexes, not MBL.
D: Terminal pathway (also known as the membrane attack complex) is the final step of all complement pathways, not specifically triggered by MBL.
In a patient with a CD4 count less than 200, the most important nursing assessment would include:
- A. Bowel movements.
- B. Urinary output.
- C. Fever.
- D. Blood pressure.
Correct Answer: C
Rationale: A CD4 count below 200 indicates advanced HIV infection (AIDS), making the patient highly susceptible to opportunistic infections. Fever is a key sign of infection and requires immediate attention. Bowel movements and urinary output are less urgent priorities in this context.
Which of the following is NOT true with respect to T cell development?
- A. It establishes MHC restriction of the T cell repertoire
- B. It takes place in the thymus
- C. Thymic dendritic cells are involved
- D. It only occurs after the naïve T cell has been activated by antigen
Correct Answer: D
Rationale: The correct answer is D because T cell development starts in the thymus while the naïve T cell activation by antigen occurs outside of the thymus. T cell development involves positive and negative selection, establishing MHC restriction, and interaction with thymic dendritic cells for maturation. Naïve T cells are activated by antigens in the periphery, not during T cell development in the thymus. Therefore, D is the correct answer as it does not align with the process of T cell development.
Which of the following lymphoid tissues has both hematopoietic and immune functions and acts as an emergency reservoir of blood and filters the blood as well?
- A. Tonsils and adenoids
- B. Thymus gland
- C. Spleen
- D. Lymph nodes
Correct Answer: C
Rationale: The spleen has both hematopoietic and immune functions acting as a blood filter and reservoir and plays a key role in removing old or damaged red blood cells.