Question

ADA deficiency results in
A. Increased risk of infertility
B. The inability of the immune system to function normally
C. Chromosomal disorders
D. The decrease in the yield of crop plants

Answer 1

Hint: Various enzymes are working in our body to coordinate its functionality. The genetic or chromosomal disorders are passed on to generations when there is a mutation in them. But any change in the enzymes metabolism can affect only the particular generation.

Complete answer:
What is ADA? ADA is Adenosine Deaminase is a genetically inherited disorder that will damage the immune system. It is capable of causing SCID (severe combined immunodeficiency). The people suffering from this will lose all their immunity to fight against foreign microbes and pathogens.
Option A: Increased risk of infertility: ADA deficiency has no direct link to increased infertility but as the body has no immune system, it will become difficult for a person to reproduce well.
Option B: Inability of the immune system to function normally: ADA is an autosomal recessive disorder which will make a person lose his immunity to fight against the pathogens. Adenosine deaminase’s deficiency leads to accumulation of deoxyadenosine which will block the metabolic pathways of DNA synthesis and the purine salvage pathway.
Option C: Chromosomal disorders: ADA deficiency is a genetic disease but it is genetically passed from the parents to the child usually from the mother as it is “X” linked chromosome disorder. But it is caused by the deficiency of the ADA enzyme. It is not due to any mutation in the chromosomes.
Option D: Decrease in the yield of crop plants: It is an enzyme in the mammalian cells whose primer work is to expel the deoxyadenosine which is formed at the time of DNA breaking. It is toxic to us.

So the answer is option B: Inability of the immune system to function normally.

Note:
It becomes fatal if not diagnosed earlier. There are enzyme replacement therapies, stem cell transplant etc to save the sufferer. It is measured in one’s pleural fluid. It is usually tested to find any sign of Mycobacterium tuberculosis.