Here's how it works:
1. DNA in the nucleus contains the genetic code. This code dictates the production of proteins.
2. Transcription: The DNA sequence for a specific protein is copied into a molecule of mRNA.
3. mRNA leaves the nucleus. It travels through pores in the nuclear membrane.
4. Translation: The mRNA reaches a ribosome, where the genetic code is "read" and used to assemble amino acids into a specific protein.
So, mRNA acts as a messenger, carrying the instructions from the nucleus (DNA) to the ribosomes (where proteins are made) in the cytoplasm.