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AP Bio: Wednesday, 2.16.11 Planning Lab 6A; Mutations. Homework: Study for Test on Molecular Genetics Do Now: Get a copy of Lab 6A: Transformation Today’s Goals: Design a procedure for genetically engineering E. coli cells to glow. Describe the effects of different types of mutations.
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AP Bio: Wednesday, 2.16.11Planning Lab 6A; Mutations • Homework: • Study for Test on Molecular Genetics • Do Now: • Get a copy of Lab 6A: Transformation • Today’s Goals: • Design a procedure for genetically engineering E. coli cells to glow. • Describe the effects of different types of mutations. • Agenda: • Mini-Lecture: Intro to Lab 6A – Transformation • Explanation of Lab Report • In Lab Groups: (1) Use the colored cards to make a flow chart and then a procedural list for completing this lab. (2) Complete the Computer-Based Mutations Lab. Print and hand to me when finished.
AP Biology Lab 6:Genetic EngineeringviaBacterial Transformation Making E. coli glow like jellyfish Amy Dickson, Prospect Hill Academy Charter School All images by Christine Rodriguez and Amy Dickson
GOALS OF THIS LAB PROJECT: • Make E. coli bacteria glow like jellyfish • By inserting the GFP (green fluorescent protein) gene from a jellyfish into a bacterial plasmid • Control when the bacteria express this protein • By connecting the GFP gene to an “on/off” switch that causes it to be expressed only in certain environments
WHY SHOULD WE DO THIS? Genetic Engineering is now widely used: • Bacteria that produce human insulin • Corn that produces insecticide • Rice that produces extra vitamin A • Goats that produce spider silk
DNA RNA Protein Trait Green Fluorescent Protein • GFP Gene • found in jellyfish • engineered into bacteria GLOWING CELLS WHY SHOULD WE DO THIS? To SEE the Central Dogma in action:
DNA RNA Protein Trait WHY SHOULD WE DO THIS? To SEE the Central Dogma in action: X on Trait To understand how gene expression is regulated - how cells (and the scientists who manipulate them) control when genes are turned on/off.
A BIT OF BACKGROUND ON GENE REGULATION • Promoter: • A short DNA sequence upstream of a gene where RNA pol. binds to start transcription • Serves as the on/off switch for the gene blocking it turns the gene off • Why do this? • Making proteins only when needed saves energy and materials
A BIT OF BACKGROUND ON GENE REGULATION • Example: • Arabinose is a sugar that bacteria can digest • But no need to make enzymes unless arabinose is around • Normal condition: Promoter blocked by Ara repressor • In presence of arabinose: repressor is inactivated; gene is turned on genes for arabinose-digesting enzymes promoter genes not expressed Ara repressor (active) Arabinose sugar binding site genes expressed! Arabinose sugar (inducer)
QUICK REVIEW Promoter - Plasmid - Transformation - an “on/off” switch for a gene a small, circular piece of bacterial DNA that is not part of the chromosome a process in which bacteria take up DNA from their environment - can be triggered by electric shock or heat shock
STARTING MATERIALS E. coli cells • sensitive to antibiotics • can’t glow • competent - able to be transformed Bacterial chromosome
AmpR Ara promoter STARTING MATERIALS • Plasmid containing: • Ampicillin resistance gene (always expressed) • Ara promoter - turned on in the presence of arabinose
GFP gene STARTING MATERIALS Jellyfish DNA GFP = Green Fluorescent Protein glows under UV light
AmpR Ara GFP STARTING MATERIALS E. coli cells Plasmid Jellyfish DNA
AmpR GROW ON AN AGAR PLATE GFP Ara … that can GLOW! END RESULT Recombinant Bacteria…
makes all transformed bacteria resistant to ampicillin controls GFP gene expression only turned on in the presence of arabinose HOWEVER… things are actually a bit more complex. AmpR pGLO plasmid GFP Ara promoter
pGLO YOUR TASK: Design an experimental procedure for genetically engineering glowing bacteria. Goals to consider: #1 - Make recombinant bacteria #2 - Select for only the recombinant bacteria #3 - Make the recombinant bacteria glow only when we want them to. #4 - Establish a control for your experiment to demonstrate that it’s the plasmid that causes ampicillin resistance and the ability to glow.