Where does splicing not occur in cellular organisms?

Splicing refers to the process of removing introns from pre-mRNA and joining exons together to form mature mRNA, a crucial step in eukaryotic gene expression. In eukaryotic organisms such as yeasts, plants, and animals, splicing typically occurs as part of the maturation of the primary RNA transcript.

Bacteria, on the other hand, are prokaryotic organisms and do not have introns in their genes. Their mRNA is often transcribed directly from DNA and can be translated into proteins almost immediately after synthesis, without the need for splicing. Thus, the process of splicing is not applicable in bacteria, making this the correct answer. While splicing is a fundamental feature of gene expression in eukaryotic cells, it is absent in bacterial cells, defining their method of managing gene expression differently from more complex organisms.