ATI RN
Chapter 15 The Lymphatic System and Immunity Review Questions Questions
Question 1 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 2 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 3 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.
Question 4 of 5
Which of the following cell types is responsible for the humoral immune response?
Correct Answer: A
Rationale: B cells produce antibodies in the humoral immune response, targeting extracellular pathogens, unlike neutrophils, NK cells, or macrophages.
Question 5 of 5
Why has it been so difficult for researchers to develop effective antivirals for HIV?
Correct Answer: B
Rationale: HIV's rapid mutation rate hinders antiviral development, more than its replication strategy, T cell damage, or transmission mode.