The primary transcript from a typical eukaryotic gene contains introns as well as exons. Exons are the coding regions whereas introns are non coding regions. Introns are removed from the primary transcript or pre mRNA by a process called RNA splicing. 

B. RNA molecules are synthesised by an enzyme called RNA polymerase which uses a segment of a single strand of DNA as a template strand to produce a strand of RNA, complementary to base sequence to the template DNA. The RNA formed is messenger RNA or mRNA.

C. In prokaryotes, transcription and translation occur simultaneously in the cytoplasm because there is no nucleus in prokaryotes and as the RNA is produced from transcription, translation of RNA starts simultaneously.

D. Prokaryotes do not have a nucleus like eukaryotes where RNA is synthesised from transcription in the nucleus and then it is transported to the cytoplasm for translation. Hence both transcription and translation occur simultaneously in the cytoplasm in prokaryotes.

Hence, all the statements except statement A, hold true for the protein synthesis in prokaryotes.

Prokaryotic Cell Components

• m-RNA: Messenger RNA (m-RNA) is found in both prokaryotic and eukaryotic cells. It is responsible for carrying the genetic information from the DNA to the ribosomes for protein synthesis.

• r-RNA: Ribosomal RNA (r-RNA) is also present in both prokaryotic and eukaryotic cells. It is a crucial component of the ribosomes where protein synthesis occurs.

• Simultaneous Transcription and Translation: Prokaryotic cells are known for their ability to carry out simultaneous transcription and translation. This means that the processes of transcription (making RNA from DNA) and translation (making proteins from RNA) can occur at the same time in prokaryotic cells due to the absence of a nuclear membrane separating the two processes.

• sn-RNA: Small nuclear RNA (sn-RNA) is a type of RNA found in eukaryotic cells, specifically in the nucleus. It plays a role in processes such as RNA splicing and regulation of gene expression. Prokaryotic cells do not have a nucleus or carry out RNA splicing in the same way as eukaryotic cells, so sn-RNA is not found in prokaryotic cells.

In summary, all of the components mentioned can be found in prokaryotic cells except for sn-RNA, which is unique to eukaryotic cells. Prokaryotic cells are simpler in structure compared to eukaryotic cells, lacking a nucleus and other membrane-bound organelles, but they are still able to carry out essential processes such as protein synthesis efficiently.