Which statement about cystic fibrosis is true? (1 point) Carriers have an advantage over people
O who do not have the cystic fibrosis mutation.
Cystic fibrosis is
• caused by a deletion
of one codon in the
DNA molecule.
Cystic fibrosis is caused by a mutation
• in which a dominant allele replaces a recessive allele.
Cystic fibrosis affects a person's ability to make normal red blood cells.
The statement "Cystic fibrosis affects a person's ability to make normal red blood cells" is not true. Cystic fibrosis primarily affects the lungs, pancreas, and digestive system, but not the production of red blood cells.
The correct statement about cystic fibrosis is the following: Cystic fibrosis affects a person's ability to make normal red blood cells.
To determine which statement about cystic fibrosis is true, we can examine each statement and eliminate the false options.
1. Carriers have an advantage over people who do not have the cystic fibrosis mutation: This statement is incorrect. Carriers of the cystic fibrosis mutation may not show symptoms, but they do not have an advantage over individuals who do not have the mutation.
2. Cystic fibrosis is caused by a deletion of one codon in the DNA molecule: This statement is also incorrect. Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, but it is not specifically a deletion of one codon. The CFTR gene mutation leads to a faulty protein that affects the movement of salt and water in and out of cells.
3. Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele: This statement is incorrect as well. Cystic fibrosis follows an autosomal recessive inheritance pattern. This means that two copies of the mutated CFTR gene (recessive allele) are necessary to develop cystic fibrosis.
4. Cystic fibrosis affects a person's ability to make normal red blood cells: This statement is false. Cystic fibrosis primarily affects the respiratory and digestive systems, not the production of red blood cells. The faulty CFTR protein causes the production of thick and sticky mucus that can obstruct the airways, leading to respiratory problems.
Therefore, none of the given statements are true. The correct statement would be: Cystic fibrosis primarily affects the respiratory and digestive systems due to the mutation in the CFTR gene, specifically a recessive allele.