Question

Sickle-cell anemia is caused by a mutation of one nucleotide in a gene. The type of mutation that causes sickle-cell anemia is known as:

A) a frame-shift mutation
B) an insertion mutation
C) an inversion mutation
D) a point mutation

Answer 1

D) a point mutation

Sickle-cell anemia is caused by a specific point mutation in the gene that codes for hemoglobin. This mutation results in the substitution of one nucleotide in the DNA sequence, leading to a change in a single amino acid in the hemoglobin protein.

Answer 2

Sickle-cell anemia is caused by a point mutation, which involves the substitution of one nucleotide base resulting in a change in the protein hemoglobin, ultimately leading to the disease's characteristically sickle-shaped red blood cells.

Step-by-step explanation:

The type of mutation that causes sickle-cell anemia is known as a point mutation. This specific mutation involves the replacement of a single nucleotide base in DNA, leading to a change in a single amino acid in the protein hemoglobin. In the case of sickle-cell anemia, the amino acid glutamic acid is replaced with valine, altering the hemoglobin's shape and functionality. Consequently, erythrocytes (red blood cells) become sickle-shaped, which impairs their ability to carry oxygen effectively and leads to the symptoms associated with anemia.