6.5 Flashcards
regulatory sequences
portions of DNA that interact with regulatory proteins to control transcription, control expression of genes
positive inducible operons
activator proteins cannot bind to DNA segment, if inducer is bound it can bind to DNA and activate transcription
positive repressible operons
activator normally bound to DNA, when corepressor binds to activator, prevents transcription (can’t bind to DNA)
prokaryotes
expression of genes regulated by operons/inducers
eukaryotes
expression regulated at many stages
promoter
RNA polymerase attaches to DNA to begin tranascription
operator
control access of RNA polymerase to a group of genes (off/on switch)
structural genes
code for enzymes produced by that operon
metabolic pathways can be controlled by:
feedback inhibition, cells can adjust production of certain enzymes
operon
consists of promoter, operator, and genes whose products function in a common pathway
repressor
bins to the operator and blocks attachment of RNA polymerase to the promoter, preventing transcription
regulatory gene
gene that codes for a protein that controls transcription of a gene (repressor)
corepressor
small molecule that binds to a bacterial repressor protiein and changes its shape allowing it to bind to operator and switch an operon off/on
histone acetylation
addition of acetyl group to amino acid in a histone tail may promote transcription by opening up chromatin structure
control elements
segments of non coding DNA having nucleotide sequences that serve as binding sites for transcription factors which regulate transcription
