Gene regulation Flashcards
(22 cards)
Gene regulation
Definition of gene regulation
The ability to cells to control their level of gene expression
Gene regulation
Why are the majority of gene regulated?
So proteins are only produced at certain times in certain amounts
Gene regulation
Constitutive genes
Unregulated
Have constant levels of expression
Gene regulation
Benefits of gene regulation
Conserves energy
Ensures genes are expressed in appropiate cell types and at the right stage in development
Gene regulation
What is gene regulation often used for in prokaryotes?
To respond to changes in the environment
Gene regulation
What effect does gene regulation in eukaryotes have?
Produces different cell types
Cell differentiation
Gene regulation
At what point is gene regulation in bacteria most likely to occur?
Transcription
Gene regulation
At what points can gene regulation occur in eukaryotes?
Gene regulation
Transcriptional regulation in bacteria
Involves regulatory transcription factors
Bind to DNA in vicinity of a promoter and affect transcription of one or more nearby genes
Gene regulation
Types of transcriptional regulation in bacteria
Negative control
- Represors inhibit transcription
Positive control
- Activators increase rate of transcription
Gene regulation
Small effector molecules in bacterial transiptional regulation
Bind to regulatory transcription factor
Causes conformational changes
Determines if regulatory transcription factor can bind to DNA
Gene regulation
What are the 2 domains in regulatory transcription factor that respond to the small effector molecules?
Site where protein binds to DNA
Site for small effector molecule
Gene regulation
Operon
In bacteria
Cluster of genes under transcriptional control of one promoter
Transcribed into polycistronic mRNA which encode more than one protein
Gene regulation
What does operons allow?
Bacteria to regulate a group of genes with a common function
Gene regulation
Polycistronic mRNA
mRNA that encodes more than one protein
Gene regulation
lacP
Promoter for the lac operon
Gene regulation
What are the 3 structural genes in the lac operon and what do they encode for?
lacZ - ß-galactosidase
lacY - lactose permease
lacA - galactosidase transacetylase
Gene regulation
What are the two regulator sites near the lac promoter?
lacO - operator
CAP site
Gene regulation
lacO - operator
Provides binding site for repressor protein
Gene regulation
CAP site
Regulatory site near lac promoter
Activator protein binding site
Gene regulation
What does the lacl gene code for?
lac repressor
