beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____.

The first step leading to the synthesis of a polypeptide within the nucleus is transcription. During transcription, a specific segment of DNA (a gene) is unwound, and a complementary strand of messenger RNA (mRNA) is synthesized using one DNA strand as a template. This process copies the genetic information needed to produce a polypeptide into an mRNA molecule, which then leaves the nucleus to be translated into protein in the cytoplasm.