Chapter 18 notes (test Flashcards
Are all an organism’s genes being expressed at the same time?
no, they can be turned on and off as needed
Both _________and____________ can control gene expression in response to ______________
prokariotic and eukaryiotic cells, changing environmental conditions
the regultaion of gene expression controls cell ________ in the proccess of _____________ developement
differentiation, embryological
Genes are turned on and off by starting or stopping what?
transcription
Operator
a single switch that control genes in bacteria
a single switch that controls genes in bacteria
operator
Operons
a unit of genetic function which consists of a promoter, operator, and genes
a unit of genetic function which consists of a promoter, operator, and genes
operon
Repressible operons
Transcription is usually on, but can be turned off or repressed
Transcription is usually on, but can be turned off or repressed
Repressible operons
Repressible operons usually function in ?
anabolic pathways
Repressor
inactive by itself, binds to the operator and blocks the RNA polymerase, a small protein that can turn the operon off
Regulatory gene
makes a specific protein to turn the operator off
corepressor
inactive by itself, binds to the repressor to activate it
Inducible Operons
Transcription is usually off, but can be turned on, or induced
Transcription is usually off, but can be turned on, or induced
inducible operons
inactive by itself, binds to the repressor to activate it
corepressor
inactive by itself, binds to the operator and blocks the RNA polymerase, a small protein that can turn the operon off
repressor
makes a specific protein to turn the operator off
regulatory genes
Inducible operons usually function in….
catabolic pathways
inducer
a small molecule that inactivates the repressor
Positive gene regulation
proteins bind to DNA and encourages transcription
a small molecule that inactivates the repressor
inducer
proteins bind to DNA and encourages transcription
positive gene regulation
Inducible operons usually function in….
catabolic pathways
inducer
a small molecule that inactivates the repressor
Positive gene regulation
proteins bind to DNA and encourages transcription