Impacts of mutations on proteins (pls )

1. what is a mutagen? what is a mutation?

2. when the mutation caused the addition of one base into the dna sequence, there was one base (a g) left over at the end. does this one base code for an amino acid? why or why not?

3. compare a normal dna sequence to the mutated dna sequence. is the entire sequence of dna different? explain

4. compare a normal protein to a mutated protein. is the entire protein different? explain.

5. predict how this small change could impact the function of the protein with the mutation compared to the protein without?