D) Based on your above answers, do all substitutions cause a change in the amino acid sequence of a protein? Explain

No, they do not all cause a change in amino acid sequence of a protein.

Explanation:

Substitution mutation is the type of mutation that results when the nucleotide base of a gene is replaced by another base in the sequence. A substitution mutation can result into three different types of mutation namely; silent mutation, missense mutation, and nonsense mutation.

- In silent mutation, the nucleotide base that gets replaced by another still forms a codon that encodes the same amino acid as in the original sequence. e.g if guanine replaces adenine in the sequence, TTA to form a mutated sequence, TTG. This mutated codon (TTG) still encodes LEUCINE amino acid just as TTA does. Hence, there is no effect on the resulting amino acid sequence. This portrays that NOT ALL SUBSTITUTIONS cause a change in amino acid sequence of a protein.