Answer:
A substitution in one of the amino acids changed the ApoA-1 protein and increased its effectiveness against the heart disease.
Explanation:
Mutation is generally any change in the nucleotide sequence of the genetic material (DNA). Mutation is of different types depending on its effect on the resulting protein. According to the question, a point mutation that occurs to the amino acid sequence of the ApoA-1 protein. It is called point mutation because it involves a single amino acid.
A point mutation can either occur through substitution, deletion or insertion. If one of the amino acids gets deleted in the sequence or another amino acid is added/inserted to the sequence, it will change the reading frame of the amino acid sequence, hence, leading to the production of a different protein that is not ApoA-1 protein. Ultimately, the function of removing Cholesterol from the blood will not be achieved. The silent mutation will not alter the amino acid sequence, hence, produce the same ApoA-1 protein.
However, a substitution mutation affecting one of the amino acids in the sequence, may result in the production of a protein with an enhanced function i.e. in the case of ApoA-1 protein, a substitution mutation can increase Its effectiveness against heart disease.
