regulation of gene expression Flashcards
common themes of gene regulation
- Genes and regulatory elements (non transcribed DNA) 2. Levels of gene regulation (replication, transcription, translation, etc) 3. DNA-Binding proteins (transcription)
regulatory protein domains
the functional part of the protein, binds to DNA
regulatory protein motifs
simple structures found in the binding domain that fits into the major groove of DNA
What level does most regulation occur at in bacteria?
transcription
operon (bacteria)
transcriptional unit consists of promoter + operator + structural genes
where can E. coli be found?
in our large intestines
what is in the lac operon?
promoter lacP, operator lacO, structural genes lacZ, lacY, and lacA
how is lac operon controlled?
negative control. in absence of lactose it is repressed and does not transcribe.
is the repressor protein gene lacI part of the operon?
no. it has its own promoter and is located away from the operon
how does the lac operon repressor work?
in the absence of lactose the repressor binds to the operator and represses transcription. in the presence of lactose, allolactose will bind to repressor and it will release from operator
partial diploid
full bacterial chromosome + an extra piece of DNA on F plasmid
lacZ+
functional, produces B-galactosidase
lacZ-
nonfunctional, produces defective B-galactosidase
lacY+
functional, produces permease
lacY-
nonfunctional, produces defective permease