Practice question

Because bacteria lack a nuclear envelope, transcription and translation occur in same compartment and are physically coupled. As soon as Shine-Dalgarno sequence and start codon emerge from RNA polymerase, 30S ribosomal subunit binds and initiates protein synthesis while polymerase continues elongating. This coupling allows NusG to bridge RNA polymerase and leading ribosome, enhancing processivity and synchronizing rates. It also underpins transcriptional attenuation, polarity, and antitermination. In eukaryotes, nuclear membrane separates mRNA synthesis in nucleus from translation in cytoplasm, precluding such simultaneous coupling.