Answer:
Step-by-step explanation:
From the options:
The DNA mutation increases the number of amino acids in hemoglobin, which causes a change in the shape of red blood cells.
The DNA mutation causes a change in the amino acid sequence for hemoglobin, which causes a change in the shape of red blood cells.
The DNA mutation decreases the number of amino acids in hemoglobin, which causes a change in the shape of red blood cells.
O The DNA mutation prevents formation of hemoglobin, the absence of wirich causes a change in the shape of red blood cells.
The correct answer would be that "The DNA mutation causes a change in the amino acid sequence for hemoglobin, which causes a change in the shape of red blood cells. "
The sickle-cell anemia is caused by a change in the amino acid sequence of the hemoglobin - specifically, as a result of the substitution of the sixth amino acid, glutamic acid, by valine in the beta subunit of the proteins that make up the hemoglobin. A single base substitution causes glutamic acid to be changed to valine.
The normal hemoglobin is disc-shaped and is able to effectively carry oxygen in the blood, unlike the sickle-cell hemoglobin which has the sickle shape and is not able to effectively carry oxygen in the blood.