__ is a single point mutation that affects the amino acid difference on the __ chain. sickle cell anemia/gamma sickle cell anemia/delta sickle cell anemia/beta sickle cell anemia/alpha

## Step 1<br />Sickle cell anemia is a genetic disorder that affects the shape and function of red blood cells. This disease is caused by a single point mutation in the gene that codes for the beta chain of hemoglobin, the protein in red blood cells that carries oxygen.<br /><br />## Step 2<br />The mutation in the beta chain of hemoglobin leads to the production of abnormal hemoglobin, known as hemoglobin S. This abnormal hemoglobin causes the red blood cells to become rigid and sickle-shaped, rather than the normal disc shape.<br /><br />## Step 3<br />The sickle-shaped cells can block blood flow in small blood vessels, leading to pain and organ damage. The other options, such as gamma, delta, and alpha chains, are not affected by the mutation responsible for sickle cell anemia.