20 POINTS The following question has two parts. First, answer Part A. Then, answer Part B.

Caused by a mutation, sickle cell anemia is a disorder that affects hemoglobin, the red blood cell molecule that carries oxygen to cells throughout the body. The β chain of the hemoglobin protein is a single chain of amino acids and is 147 amino acids long. In humans, the gene that encodes for the β chain is located on chromosome 11. The diagrams show the DNA, RNA, and amino acid sequence of an unaffected person and a person with sickle cell anemia.

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Part A:

Where does the mutation that causes this disorder occur?

A
The mutation occurs on the DNA.

B
The mutation occurs on the RNA.

C
The mutation occurs on the ribosomes.

D
The mutation occurs on the amino acid.

Part B:

Which BEST describes the result of this mutation?

A
The entire sequence of amino acids is changed.

B
The RNA strand does not code for the correct amino acids.

C
The change in amino acids shortens the polypeptide sequence.

D
The alternation of a single nucleotide encodes for a different amino acid.