BIO 2600 Study Guide - Gene Expression, Cellular Differentiation, Multicellular Organism
Document Summary
How is gene expression controlled: a bacterium expresses its genes selectively to make the enzyme needed to digest food only when food is available. Differentiated cells contain all the genetic instructions necessary to distract the formation of a. Different cell types of a multicellular organism contain the same dna but produce different set of. Eukaryotic gene expression can be regulated at many of the steps in the pathway from dna to rna to. Rna synthesis begins, plus a sequences of approx. 50 nucleotide pairs that extend upstream from the initiation site: this upstream region contains sites that are required for the rna polymerase to recognize the promoter, although they do not bind to rna polymerase directly. Instead, these sequences contain recognition sites for proteins that associate with active polymerase: sigma factor in bacteria, general transcription factors in eukaryotes. To have any effect, these sequences must be recognized by proteins called transcription regulators.
