Gene Expression and mRNA processing

what happens in prokaryotic gene expression

Lac operon occurs

what is lac operon

DNA sequence that controls the production of enzymes for the digestion of lactose

what are the 3 parts of the lac operon

promoter, operator, gene

during prokaryotic gene expression what happens when lactose is absent

the promoter region is covered by a repressor protein blocking the transcription of the gene

during prokaryotic gene expression what happens when lactose is present

when lactose is present in the cytoplasm it pulls the repressor off of the operator region, allowing the RNA polymerase to transcribe the gene and the lactose digestive protein will be translated

what happens in eukaryotic gene expression

because the eukaryotic cell is more complex, gene expression can be controlled at many places/times

what do transcription factors do during eukaryotic gene expression

transcription factors help RNA polymerase recognize promoter regions of DNA

what do regulatory genes do during eukaryotic expression

there are regulatory genes that control the expression of other genes, turning them on and off

what is mRNA processing do

DNA has long sections of noncoding regions called “introns” are removed and then the coding region’s “exons” are spliced together to make a function mRNA transcript

what does the presence of introns do

the presence of introns may be protection from mutations or might be the eukaryotic genome being so big