BIOC 300B Lecture Notes - Lecture 32: Homeobox, Histone H2B, Alpha Helix
Document Summary
Cells exposed to hormones and growth factors will change substantially in shape, growth rate etc. Many di erent cell types present in multicellular organism. Gene expression: is the combined process of transcription of a gene into mrna, the p recessing of that mrna and its translation into protein. First and foremost controlled at level of transcription. Achieved by interplay between proteins that bind speci c regions of dna sequences and sites. their dna-binding. Prokaryotic dna-binding proteins bind speci cally to regulatory sites in operons: E. coli rely on glucose as source of carbon energy. Glucose low e. coli use lactose as carbon source. Essential enzyme is needed in metabolism of lactose--> beta-galactosidase. The presence of lactose induces a large increase in beta-galactosidase by evoking the synthesis of a new enzyme rather than activating an inactive precursor. Two other proteins are synthesized in concert with beta-galactosidase. Thiogalactoside transacetylase-not essential for lactose metabolism but role in detox.