Transcription and translation occur in all cells. Transcription, the process of creating messenger RNA (mRNA) by copying DNA, occurs in the nucleus in eukaryotes. In prokaryotes, which lack a membrane-bound nucleus, transcription occurs in the cytoplasm along with all other cell functions. Translation, the process of utilizing the mRNA to create proteins, occurs in the cytoplasm in both types of cell. Consequently, eukaryotes, which separate the two functions by having transcription happen within the nuclear envelope and translation happen outside of it, cannot do simultaneous transcription and translation for a single protein, while prokaryotes can.
Control mechanisms exist in both types of cells; in prokaryotes, repressor molecules bind to the DNA. In eukaryotes, enhancers are more common.