BSC 203 Chapter Notes - Chapter 5: Sv40, Tata Box, Arabinose
Document Summary
Prokaryotic gene expression is primarily controlled at the level of transcription. The arabinose operon undergoes both positive and negative regulation by a single. The ara operon is regulated by the arac protein. The arac protein regulates its own synthesis by repressing transcription of its gene. Once the arac protein begins to repress it starts by binding to arai1 and arao2 and the dna forms a loop. The loop prevents rna polymerase from binding to the promoter of the ara operon, and blocking transcription. In prokaryotes gene expression is regulated primarily at the transcriptional level. In eukaryotes gene expression is regulated at many levels (epigenetic, transcriptional, nuclear shuttling, post-transcriptional, translational, and post-translational) Prokaryotic cells can only regulate gene expression by controlling the amount of transcription. As eukaryotic cells evolved, the complexity of the control of gene expression increased. Transcription occurs only within the nucleus, and translation occurs only outside the nucleus within the cytoplasm.
