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Question #45465
The Question
A pediatric patient exhibits a near-total absence of functional T-lymphocytes. The immunodeficiency could theoretically stem from either an endocrine failure (Thymosin deficiency) or a metabolic failure (Adenosine Deaminase deficiency). Which of the following statements correctly distinguishes the pathogenesis of ADA deficiency from Thymosin deficiency?
Options
- A.
ADA deficiency prevents the initial formation of hematopoietic stem cells in the bone marrow, whereas Thymosin deficiency halts their migration to the thymus.
- B.
ADA deficiency causes the accumulation of toxic purine metabolites that destroy lymphocyte progenitors, whereas Thymosin deficiency represents a failure of peptide-driven differentiation.
- C.
ADA deficiency selectively impairs humoral immunity by destroying B-lymphocytes, whereas Thymosin deficiency exclusively impairs cell-mediated immunity.
- D.
ADA deficiency is characterized by the autoimmune destruction of the thymus gland, whereas Thymosin deficiency is a genetic defect in pyrimidine metabolism.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Thymosin Specificity|ADA Deficiency Genetic Correction|Down/Klinefelter/Turner Syndrome Karyotypes
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between a metabolic/enzymatic prerequisite for cell survival (ADA) and an endocrine signal for cell differentiation (Thymosin).
Students often confuse the exact reason WHY lymphocytes are absent in SCID, assuming it is a primary production failure in the bone marrow rather than a survival failure due to toxic metabolite accumulation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Thymosin Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |