ATI RN
Immune System Multiple Choice Questions Questions
Question 1 of 5
Which of the following is true about antigen presentation through MHC II molecules?
Correct Answer: D
Rationale: MHC II presents exogenous peptides to CD4+ Th cells ; endogenous and killer T cells are MHC I, not on all cells .
Question 2 of 5
The walls of lymphatic vessels are similar to those of cardiovascular
Correct Answer: B
Rationale: Lymphatic vessel walls resemble veins with thin walls and valves; arteries are thicker, capillaries lack valves, and distributing arteries are muscular.
Question 3 of 5
In patients with lymphomas, the cancer cells invade the bone marrow and destroy the environment required for normal hematopoiesis. This leads to bone marrow failure, which disrupts the production of hematopoietic cell lineages. All of the following cell types would be affected by this EXCEPT:
Correct Answer: D
Rationale: Bone marrow failure affects hematopoietic cells (A, B, C, E) derived from stem cells; endothelial cells are non-hematopoietic and unaffected.
Question 4 of 5
The classical complement pathway is initiated by C1q binding to the surface of a pathogen. In some cases, C1q can directly bind the pathogen, for instance by recognizing proteins of bacterial cell walls, but in most cases C1q binds to IgM antibodies that are bound to the pathogen surface. How does this IgM-binding feature of C1q contribute to rapid, innate immune responses rather than to slow, adaptive responses?
Correct Answer: B
Rationale: Pre-existing natural IgM enables rapid C1q activation; B-cell secretion is adaptive, CRP or inflammation are secondary.
Question 5 of 5
One striking feature of TCR interactions with peptide:MHC complexes is that amino acid residues in the MHC protein are as important to the TCR binding strength as are amino acid residues in the pathogen-derived peptide. This feature is in contrast to antigen recognition by antibodies, which is a direct interaction that is independent of other host proteins. Based on the different functions of T cells versus antibodies in the adaptive immune response, the fact that TCRs recognize components of both the MHC and the bound peptide exists to:
Correct Answer: D
Rationale: TCR-MHC recognition targets cell-associated antigens ; not just evasion or constraints , antibodies handle free antigens.