Cellular control/regulation of gene expressions Flashcards
(25 cards)
What is the definition for gene mutations?
A change in the DNA’s Base sequence (usual during gene replication)
What increases the rate of mutations?
Mutagenic agents like radiation cuz cancer- (L cancer)
What are the 3 types of gene mutation?
Deletion - Nucleotide is removed which causes a frame shift
Substitution - A base is subbed out for a diff one
Insertion - 1 more nucleotide is added to the sequence = frame shift
What does is mean for a gene to be expressed?
When a gene is transcribed and translated into a protein its said t be expressed
What do regulatory genes do?
They control the expression of another gene/control of structural genes via production of a transcription factor
What do structural genes do?
They code for proteins that have a function in the cell
What do promoters do?
there’s more than you think
They enable the transcription of structural genes - As it has a binding site for RNA polymerase to allow said transcription
Can you please explain the 4 steps of a transcription factor
1)regulatory gene produces a repressor protein
2)repressor protein binds to operator
3)RNA polymerase cant bind to operator
4)RNA polymerase cant transcribe structural genes
Where are operator genes found only?
They are only in Prokaryotes NOT eukaryotes
What is a cluster?
All of the structural genes
What is an operon?
Promoter, Operator and all structural genes
Def: A cluster of structural genes under the control of 1 promoter
What happens with the LAC operon when lactose isnt present?
LacI(regulatory) produces a repressor protein which binds to LacO which inhibits RNA polymerase form being able to transcribe
What happens with the LAC operon when lactose IS present?
LacI(regulatory) produces a repressor protein
Lactose binds to the repressor protein and changes its tertiary structure
Its now unable to bind to LacO so RNA polymerase can transcribe
What is the process of a Eukaryotes operon?
Regulatory gene produces an inactive transcription factor
Hormone binds to it and makes it active
It binds to the promoter and stimulates transcription
NO OPERATOR
What are the 4 differences between prokaryotes and eukaryotes operons?
-For Pro, RNA polymerase can bind to the promotor without a transcription factor but Eu must have a transcription factor
-For pro the binding site for the transcription factor is the operator, For Eu its the promoter
-For Pro the transcription factor inhibits transcription but for eu it stimulates it
-In Pro the transcription factor is called the repressor protein but for eu its just the transcription factor
What is the Control at the Post-transcriptional level?
After transcription Primary mRNA is produced but not ready for translation so needs to undergo RNA splicing and edditing
What is RNA splicing at the Post-transcriptional level?
This is where introns (non-coding DNA) are removed
What is RNA editing at the Post-transcriptional level?
This is where some RNA bases are subbed deleted or added
After editing and splicing what does the Primary mRNA become?
Mature RNA
What is the control at the Post-translational level?
It makes sure the protein is ready Via cAMP which binds to protein kinase and phosphorylates changing it tertiary structure
What is the definition for body plans?
The observable spatial arrangements of an organisms body parts
What’s the definition of a Homeo box gene?
gene that controls the initial development of an organisms body plan. Its active in the embryonic stage of eukaryotes
-There a type of regulatory gene
How does the homeobox gene code for the body plan?
The homeobox gene produces a transcription factor
the Homeobox code for the homeodomain which is a binding site which makes it able to bind to the promotor and trancribe
What are HOX genes?
A type of homeobox gene that code for the symmetry of ANIMALS body plans
E.g 2 ears on either side
