So we have 1234 green regions, the introns in this particular mRNA and we have 12345 of these exons that contain the codons that will be used by the ribosomes to basically synthesize our polypeptide. So the major difference between these prokaryotic cells and eukaryotic cells is that our eukaryotic mrnade, once it is synthesized, it contains these introns and therefore it cannot be used directly to synthesize the proteins. It has to be modified and these introns have to be removed while the exons have to be glued, split together before that ribosome can actually synthesize the protein. And this is not true in prokaryotic cells because they don't contain the introns. And that's exactly why transcription and translation can take place at the same exact time as we'll discuss in more detail in future lectures. Now, on average in humans, a human gene contains about eight intros.