AP BIOLOGY

HEREDITY

MUTATIONS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following disorders is caused by a missense mutation?
A
Muscular dystrophy
B
Sickle Cell Anemia
C
Ty Sachs
Explanation: 

Detailed explanation-1: -Sickle cell disease is a missense mutation. It is a type of point mutation wherein the beta-haemoglobin gene converts a GAG codon into a GUG codon. Valine is produced here in the place of glutamic acid and it causes the disease.

Detailed explanation-2: -Mutations in the HBB gene cause sickle cell disease. The HBB gene provides instructions for making one part of hemoglobin. Hemoglobin consists of four protein subunits, typically, two subunits called alpha-globin and two subunits called beta-globin. The HBB gene provides instructions for making beta-globin.

Detailed explanation-3: -A genetic alteration in which a single base pair substitution alters the genetic code in a way that produces an amino acid that is different from the usual amino acid at that position. Some missense variants (or mutations) will alter the function of the protein.

Detailed explanation-4: -A common and well-known example of a missense mutation is sickle-cell anemia, a blood disease. People with sickle-cell anemia have a missense mutation at a single point in the DNA. This missense mutation calls for a different amino acid, and affects the overall shape of the protein produced.

Detailed explanation-5: -Sickle cell disease is a hereditary disease seen most often among people of African ancestry. Caused by mutations in one of the genes that encode the hemoglobin protein, the disease is inherited as an autosomal recessive trait. The mutation causes the red blood cells to take on an unusual sickle shape.

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