Answer: Deletion of 3 nucleotides in CFTR gene (phenylalanine deleted at position 508).
- A A point mutation creating a premature stop codon early in the CFTR transcript
- B Deletion of 3 nucleotides in CFTR gene (phenylalanine deleted at position 508)
- C Duplication of an entire arm of chromosome 7 during meiosis
- D Insertion of an extra nucleotide causing a frameshift in the reading frame
Correct answer: B. Deletion of 3 nucleotides in CFTR gene (phenylalanine deleted at position 508)
Explanation: Most common CF mutation: DeltaF508 -- deletion of 3 nucleotides removes phenylalanine-508 from CFTR protein, causing misfolding and degradation.
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.
Read the full Principles of Inheritance and Variation notes →