Pre AP Biology DNA Control Mechanisms

Francois Jacob (sitting) & Jacques Monod (standing)

Operon Regulation Promoter DNA trpR Regulatory gene RNA polymerase mRNA 3 5 Protein Inactive repressor Tryptophan absent, repressor inactive, operon on mRNA 5 trpE trpD trpC trpBtrpA Operator Start codon Stop codon trp operon Genes of operon E Polypeptides that make up enzymes for tryptophan synthesis D C B A

Operon Repressor DNA Protein Tryptophan (corepressor) Tryptophan present, repressor active, operon off mRNA Active repressor No RNA made

Repressor DNA lacl Regulatory gene mRNA 5 3 RNA polymerase Protein Active repressor No RNA made lacZ Promoter Operator Lactose absent, repressor active, operon off

Operon and Inducers DNAlacl mRNA 5 3 lac operon Lactose present, repressor inactive, operon on lacZ lacYlacA RNA polymerase mRNA 5 Protein Allolactose (inducer) Inactive repressor  -Galactosidase Permease Transacetylase

Transposon - Basic Insertion sequence Transposase gene 5 3 Inverted repeat 3 5 Inverted repeat

Chromatin vs. Chromosomes appearance within the cell.

DNA Control stages in Protein Synthesis Signal NUCLEUS DNA RNA Chromatin Gene available for transcription Gene Exon Intro Transcription Primary transcript RNA processing Cap Tail mRNA in nucleus Transport to cytoplasm CYTOPLASM mRNA in cytoplasm Translation Degradation of mRNA Polypeptide Cleavage Chemical modification Transport to cellular destination Degradation of protein Active protein Degraded protein

Post Translation Control of exons

Post translation control How many As on the tail?

Chaperonin Protein will stay in the cell

RER Protein will leave the cell