BIO206H5 Chapter Notes - Chapter 8: Lac Repressor, Lac Operon, Regulatory Sequence
Document Summary
The concept that genes could be switched on and off came originally from studies of how e. coli bacteria adapt to changes in the composition of their growth medium. Many of the same principles apply to eukaryotic genes. The enormous complexity of gene regulation in higher organisms, combined with the packaging of their. Dna into chromatin, creates special challenges and some novel opportunities for control. Transcription regulators are proteins that bind to dna and control gene transcription. Control of transcription is usually exerted at the step at which the process is initiated. The promoter region of a gene binds the enzyme rna polymerase and correctly orients the enzyme to begin its task of making an rna copy of the gene. Instead, these sequences contain recognition sites for proteins that associate with the active polymerase sigma factor in bacteria or the general transcription factors in eukaryotes.
