The mutation resulting in sickle cell disease changes one base pair of dna so that a codon now codes for a different amino acid

Answer: Missense mutation

Explanation:

In sickle cell the glutamic acid in the 6th position of the beta chain of HbA (normal haemoglobin) is change to valine in HbS (sickle cell haemoglobin). This occur when there's a single nucleotide mutation. The (A) nucleotide in the condon (GAG) of glutamic acid is substituted for a (T) nucleotide. This single nucleotide substitution converts a glutamic acid codon (GAG) to a valine codon (GTG), which leads to polymerization of haemoglobin molecules in red blood cells. This cause a distortion of cell to a sickle shape.