Question

Individuals with an inherited autosomal recessive disorder called primary ciliary dyskinesia (PCD) often have severe respiratory problems due to defective cilia. Males with PCD are often sterile because they produce sperm with defective flagella. Which of the following most likely explains the effect of the recessive allele?

a) The mitochondria are defective and do not produce sufficient protein to synthesize microtubules in the cilia and flagella. b) The plasma membrane of the alveoli is not permeable to carbon dioxide during respiration because it is too hydrophobic. c) The Golgi bodies secrete an enzyme that destroys the proteins in the flagella and cilia. d) The cells do not produce functional motor proteins in flagella and cilia.

Answer 1

The correct answer is option D. The cells do not produce functional motor proteins in flagella and cilia.

Explanation:

Primary ciliary dyskinesia or PCD is a very rare autosomal recessive disorder that is characterized by severe respiratory problems, Fallopian tubes, and the sperm cells flagella due to the defects in the lining of cilia present in these structures.

This recessive trait affects the gene that is responsible for the production of the motor protein for cilia and flagella and inhibits its production.

Thus, the correct answer is option D. The cells do not produce functional motor proteins in flagella and cilia.