One significant difference between gene regulation in prokaryotes and eukaryotes is that prokaryotes do not store their genes in a nucleus like eukaryotes do. Prokaryotic genes are located in the cytoplasm, and their transcription and translation can occur simultaneously, while eukaryotic genes are housed in the nucleus, where they undergo processes such as splicing (removal of introns) before being transported to the cytoplasm for translation.
To clarify the other statements:
- Eukaryotes do respond to environmental stimuli, but prokaryotes can also regulate gene expression in response to environmental changes; they do not transcribe genes randomly.
- Prokaryotes do not remove exons from mRNA; this process (splicing) occurs in eukaryotes.
- It is actually the case that prokaryotes often use operons, which are clusters of genes under the control of a single promoter, while eukaryotes typically do not.