Final answer:
A DNA sequence change from ATG to ATC is a transversion mutation that affects base pairing, changing how cytosine pairs with guanine instead of adenine, which can alter the protein's structure and function.
Step-by-step explanation:
If a base sequence of a strand of DNA is changed from ATG to ATC, it indicates a point mutation where adenine (A) remains the same, thymine (T) remains the same, but guanine (G) has been replaced by cytosine (C). This type of mutation is known as a transversion mutation.
When the changed strand attempts to base pair with its complementary strand, the cytosine (C) would pair with guanine (G) instead of the adenine (A) that would have paired with the original thymine (T).
Thus, the corresponding complementary DNA base pair would change as well. Such mutations can alter the codon within the genetic code, potentially leading to changes in the amino acid sequence during translation, which can affect the structure and function of the resulting protein.