BIOLOGY 1A03 Chapter Notes - Chapter 5: Sigma Factor, Repressor, Arabinose

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Alastair Tracey Rosa Da Silva

Document Summary

Biology 1a03; textbook notes (transcription regulation in prokaryotes) Transcription starts at the promoter end and ends at a terminator: A long dna typically contains thousands of genes, most of them coding for proteins or rna molecules with specialized functions, and hence thousands of different transcripts are produced. For example, the dna molecule in the bacterium e coli has about 4 million base pairs and produces about 4000 rna transcripts, most of which code for proteins. Each green segment indicates the position where a transcription is initiated, and each purple segment indicates the position where it ends. The green segments are promoters, regions of typically a few hundred base pairs where rna polymerase and associated proteins bind to the dna duplex. Many eukaryotic and archaeal promoters contain a sequence similar to 5 -tataaa-3 , which is known as a tata box because the tata sequence is usually present.