In phenylketonuria :-

Options

A. Absence of enzyme that converts the amino acid phenylalanine into tyrosine
B. GAG converted into GUG
C. Sterile female developed
D. Furrowed tongue

Answer

**Step-by-Step Solution:**

1. **Understanding Phenylketonuria (PKU):**
- Phenylketonuria is a genetic disorder that results in the inability to metabolize the amino acid phenylalanine due to the absence of a specific enzyme.

2. **Identifying the Enzyme Involved:**
- The enzyme that is typically responsible for converting phenylalanine into tyrosine is called phenylalanine hydroxylase.

3. **Consequences of the Absence of the Enzyme:**
- In individuals with PKU, the absence of phenylalanine hydroxylase leads to the accumulation of phenylalanine in the body.
- Instead of being converted to tyrosine, phenylalanine is converted into phenylpyruvic acid, which can accumulate and cause neurological damage.

4. **Effects on the Body:**
- The accumulation of phenylpyruvic acid in the brain can lead to severe mental retardation and other cognitive impairments if not managed through dietary restrictions.

5. **Conclusion:**
- Therefore, the correct answer to the question regarding phenylketonuria is the absence of the enzyme that converts phenylalanine to tyrosine.

**Final Answer:**
- In phenylketonuria, there is an absence of the enzyme that converts the amino acid phenylalanine to tyrosine.

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