Variations in genome structure--> prokaryotes 2 Flashcards
Which organisms initially had the CRISPR-Cas system?
Prokaryotes
What was the CRISPR-Cas system initially made as?
Defence system used by prokaryotes to protect themselves from viral infections
General idea of CRISPR-Cas?
Cutting viral DNA w/o cutting self DNA
What are spacers?
Short sequences of viral DNA stored in the prokaryotic genome
What do spacers do?
Act as memory of the past infeciton
What are spacers used for?
Creating RNA copies, which can help Cas proteins search for the matching viral DNA
What protects bacterial DNA from the Cas proteins?
Protospacer adjacent motifs
How do PAMs protect bacterial DNA from Cas protein?
PAMs are present in the viral DNA but not in the bacterial DNA
Main diff between pro and eukaryotic gene expression?
Pro don’t undergo RNA processing
Why can prokaryotes do transcription and translation simultaneously?
Prokaryotes lack a membrane bound nucleus
What are the two important regions in bacterial promoters?
-35 and -10 region
What is the -10 region also known as?
Pribnow box
What is the -35 region used for?
Recognised by the RNA polymerase
What is the -10 region used for?
Where the RNA polymerase binds to
How can bacteria control their gene expression?
Differences in promoter strength
What do regulatory genes do?
Control transcription
How do regulatory genes control transcription?
Encode regulatory RNA or proteins, which can interact w/ other DNA sequences affecting transcription
WHat is positive control?
Stimulating gene expression
What is negative control?
Inhibiting gene expression
What is an operon?
A cluster of genes controlled together by a single promoter
How is an operon transcribed?
As one mRNA molecule
What is an operon made up of?
Promoter, operator and the genes
What is the promoter used for in an operon?
Where the RNA pol binds
What is the operator used for in an operon?
Regulation–> repressors and activators can bind here
