Here's a breakdown:

* Transcription: The process of creating an RNA copy of a gene's DNA sequence. This RNA copy is called the primary transcript.

* Pre-mRNA: In eukaryotes, the primary transcript is initially called pre-mRNA. It contains both introns (non-coding sequences) and exons (coding sequences).

* Processing: Pre-mRNA undergoes several processing steps before it can become mature mRNA and be translated into protein:

* 5' capping: A modified guanine nucleotide is added to the 5' end of the pre-mRNA.

* Splicing: Introns are removed from the pre-mRNA, and exons are joined together.

* 3' polyadenylation: A tail of adenine nucleotides (poly-A tail) is added to the 3' end of the pre-mRNA.

* Mature mRNA: After processing, the pre-mRNA becomes mature mRNA, which is ready to be translated into a protein.

Key takeaway: The primary transcript in eukaryotes is pre-mRNA, which requires further processing to become mature mRNA and be translated into a protein.