Question

A scientist modified the structure of a promoter region of a gene. What could be its effect on transcription and translation?

Answer 1

Depends.

The promotor is a binding site for proteins that make it more likely that DNA will be transcribed. The more the DNA is transcribed, the more copies of mRNA are floating around. The more copies of mRNA are floating around, the more likely it is that some of them will leave the nucleus, bind to ribosomes and be translated into proteins.

So depending on whether the change in the modified promotor made it more or less likely that transcription factors (those proteins) bind, the downstream consequences in terms of protein translation could be either.