Question

the cftr protein is made up of 1,480 amino acids linked together in a chain. some humans produce a version of the cftr protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. which of the following best predicts how the amino acid deletion will affect the structure of the cftr protein? a it will have no observable effect on the structure of the cftr protein. b it will affect the primary structure of the cftr protein, but the other levels of protein structure will not be affected. c it will affect the secondary and tertiary structures of the cftr protein, but the primary structure will not be affected. d it will affect the primary, secondary, and tertiary structures of the cftr protein.

Explanation:

The primary structure of a protein is the sequence of amino acids. A deletion of an amino acid (like phenylalanine at position 508 in CFTR) changes this sequence, so primary structure is affected. Secondary structure (e.g., alpha - helices, beta - sheets) depends on the primary sequence's interactions, and tertiary structure (the overall 3 - D shape) is influenced by secondary structure and side - chain interactions. So a change in primary structure will cascade to affect secondary and tertiary structures. Option A is wrong as there is an effect. Option B is wrong because secondary and tertiary structures depend on primary. Option C is wrong as primary structure is affected. Option D correctly states that the deletion affects primary, secondary, and tertiary structures.

Answer:

D. It will affect the primary, secondary, and tertiary structures of the CFTR protein.