CH8 Flashcards
Base substitution mutation
CG turns into AT
Frame shift mutation
Base pairs are added or removed from the sequence, causing shift in sequence reading
Inducible operon
Genes that are in off mode are turned on by inducer
Repressible operon
Genes that are in are turned off by corepressor and repressor
Transcription
DNA to RNA
Translation
RNA to protein
mRNA begins T the start codon
Aug
Translation ends at nonsense codons
UAA,UAG,UGA
Unwinds dna
Helicase
Adds nucleotides to a growing chain
Also helps with editing out mistakes, removes mismatched nucleotides and replace them with the proper nucleotide
DNA polymerase
Joins small fragments into a continuous chain
DNA ligase
Segment of dna where rna polymerase initiates transcription of structural genes
Promoter
Segment of dna that controls transcription of structural genes
Operator
Set of operator and promoter sites and the structural genes they control
Operon
The repressor is active and binds to the operator preventing transcription
Repressor active, operon off
In the presence of lactose, inducer allolactose binds to the repressor protein
Inactivated repressor can no longer block transcription
Genes are transcribed, producing enzymes needed for lactose catabolism
Repressor active, operon on
Repressor inactive, operon on
In absence of tryptophan the repressor is inactive
Transcription and translation proceed
Leading to synthesis of tryptophan
Repressor active operon off
In presence of tryptophan acting as a suppressor, tryptophan binds to the repressor protein. The activated repressor binds with the operator, preventing transcription of the operon
If glucose is scarce the high level of camp activates cap and lac operon produces large amounts of mRNA for lactose digestion
Positive regulation
If both lactose and glucose is present, camp is scarce and the inactive cap is unable to stimulate transcription of lac operon
Not needed because both are present
Positive regulation
Part of an mRNA molecule that binds to a substrate and changes the mRNA structure translation is initated or stopped
Riboswitch