Transcription in protein synthesis is when the mRNA is created using the template of DNA. It is the process of transcribing DNA to mRNA which is catalyzed by RNA polymerase. Transcription encompasses manufacturing, splicing, and adding of caps and tales of the mRNA. All of these happen in the nucleus of the cell. Replication, transcription, and translation are three different terms. Replication means duplication of DNA. Transcription is the multiplication or duplication of genetic information into mRNA and translation is protein production through activities of ribosome.