BIOLOGY 1A03 Lecture Notes - Lecture 7: Lactose Permease, Beta-Galactosidase, Growth Medium

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

Document Summary

Learning objectives: describe how bacterial cells organize functionally related genes into single transcriptional units, examine how the outcomes of gene expression can be regulated based on environmental cues identify how gene expression can be negatively and positively regulated. Leads prokaryotes to have the ability to control transcription of whole gene cluster as. Francois jacob & jacques monod: 1961, discovered basic model for this type of control of gene expression in bacteria. Lac operon: model for transcriptional regulation in prokaryotes: regulation of beta- galactosidase and lactose permease expression is under control of lac operon in e. coli cells, regulatory sequences of transcription exist in lac operon. Lac l gene (structural gene) controls expression of lacz and y genes: by itself: operator allows for transcription to occur. Unit 2 -negative regulation of the lac operon: negatively regulated transcription: repressor protein binds to operator region of the operon. Result: turning off transcription since rna polymerase cannot bind to promoter region of operon.