Gene Regulation and Mutation Flashcards
gene regulation
ability of an organism to control which genes are transcribed in response to the environment
what does an operon do in prokaryotes
controls the transcription of genes in response to changes in the environment
operon
a section of DNA that contains the genes for the proteins needed for a specific metabolic pathway
What are the parts of an operon
operator, promoter, regulatory gene, and the genes coding for proteins
what is the operator
a segment of DNA that acts as an on/off switch for transcription
promoter
RNA polymerase first binds to the DNA
What does the bacteria, E coli respond to through two operon
tryptophan, amino acid, lactose
trp operon
the five genes coding for the enzymes are clustered together on bacteria - controls whether or not they are transcribed
lac operon
when lactose is present in the cell - e. coli makes enzymes that enable it to use lactose as an energy source
what does a lactose operon contain
promoter, operator, regulatory gene, and 3 enzyme genes that control lac digestion
what happens in a lac operon
a molecule (inducer) is present, inducer binds to repressor (inactivates it)
What happens when the repressor is inactivated
RNA polymerase can bind to the promoter and begin transcription
What is a lac operon called and why
inducible operon because transcription is turned on by an inducer
mutation
permanent change in a cells DNA
Point mutations
A chemical change in just one base pair and can cause a genetic disorder
