Genetic Engineering And Biotechnology

Step 1: Understanding the Concept: Adenosine Deaminase (ADA) deficiency is a genetic disorder that severely compromises the immune system, often leading to SCID (Severe Combined Immunodeficiency).
Step 2: Key Formula or Approach: Evaluate the validity of each statement by recalling the physiological role of the ADA enzyme and the various available treatments.
Step 3: Detailed Explanation: Statement I declares that ADA is crucial for the immune system to function.
This is absolutely true, as the ADA enzyme is essential for the maturation and proliferation of lymphocytes (T-cells and B-cells).
Statement II claims that ADA deficiency can be cured "only" by bone marrow transplantation.
This is false. While bone marrow transplantation is one treatment option, it is not the only one. Other treatments include enzyme replacement therapy (where functional ADA is regularly injected) and gene therapy.
Furthermore, standard textbooks explicitly state that neither standard bone marrow transplantation nor enzyme replacement therapy is completely curative unless performed at early embryonic stages.
Thus, the absolute word "only" makes Statement II factually incorrect.
Step 4: Final Answer: Statement I is true, but Statement II is false.