ATI RN
Chapter 15 The Lymphatic System and Immunity Review Questions Questions
Question 1 of 5
What is the function of programmed death 1 (PD-1) on T cells?
Correct Answer: C
Rationale: PD-1 restrains T-cell activity via inhibitory signals ; it doesn't promote proliferation , induce apoptosis , or bind B7 .
Question 2 of 5
The clonal selection theory was first proposed in the 1950s, decades before the molecular details of B and T lymphocyte development and lymphocyte antigen recognition responses were elucidated. Nonetheless, Burnet, who proposed this theory, correctly inferred several key aspects of adaptive immune responses. One key postulate that Burnet proposed was that:
Correct Answer: D
Rationale: Burnet's theory posits clonal selection where each B cell expresses one antibody type as a receptor ; other options are true but less central to his hypothesis.
Question 3 of 5
An infection in the skin, such as a pimple, often produces pus. The major component of pus is:
Correct Answer: D
Rationale: Pus is mostly dead/dying neutrophils ; oxygen , nitrogen , NETs , or epithelial cells are minor components.
Question 4 of 5
The addition and subtraction of nucleotides at the junctions between V, D, and J gene segments creates antibody proteins with wide variations in the numbers of amino acids in their CDR3 regions. This variability in CDR3 length is important as:
Correct Answer: A
Rationale: CDR3 length variability it doesn't cross placenta ; diversity is broader, not just CDR3 , or affinity .
Question 5 of 5
Anemia
Correct Answer: D
Rationale: Anemia is characterized by low hemoglobin or red blood cell levels, reducing oxygen-carrying capacity, not related to leukocytes or cancer.