What process involves the copying of the code by mRNA?

The process that involves the copying of the code by mRNA is transcription. During transcription, a specific segment of DNA is used as a template to synthesize messenger RNA (mRNA). This occurs in the cell nucleus where RNA polymerase enzyme binds to the DNA and unwinds it. The enzyme then reads the DNA sequence and assembles the corresponding RNA nucleotides, creating a complementary RNA strand that captures the genetic information encoded in the DNA.

Transcription is crucial for gene expression, as it allows the code contained in DNA to be transcribed into a form that can be translated into proteins, the functional molecules within a cell. Understanding this process is fundamental in molecular biology, as it lays the foundation for the subsequent step, translation, where the mRNA is used to synthesize proteins.