Zaymiey

🔬 Biology  ·  Principles of Inheritance and Variation  ·  NEET

Phenylketonuria is caused by the lack of an enzyme that converts:

Answer: phenylalanine into tyrosine.

  • A tyrosine into melanin pigment
  • B phenylalanine into tyrosine
  • C glucose into glycogen
  • D galactose into glucose

Correct answer: B. phenylalanine into tyrosine

Explanation: In phenylketonuria the enzyme converting phenylalanine to tyrosine is absent, so phenylalanine and its derivatives accumulate and cause mental impairment.

Monohybrid Cross: Tt x TtParent 1 (Tt)Parent 2 (Tt)gametes: T, t (from each parent)TtTtTTTtTtttRatio 1 TT : 2 Tt : 1 tt (3 tall : 1 short if T = tall is dominant)

Punnett square for a monohybrid cross between two heterozygous (Tt) parents, showing the 3:1 phenotypic ratio predicted by Mendel's Law of Segregation.

Concept context

Mendel's laws, inheritance patterns, DNA structure, and molecular biology. Core of NEET biology.

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