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Purpose of this Lab. Learn how to insert a gene into bacteria (Heat Shock)Analyze how a gene can transform an organism and express that geneProvide evidence that bacteria can take in foreign DNA in the form of a plasmidReinforce the following process: DNA ? RNA ? Protein ? TraitObserv
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1. Bacterial Transformation with (pGLO Plasmid) Lab #8: Molecular Biology
2. Purpose of this Lab Learn how to insert a gene into bacteria
(Heat Shock)
Analyze how a gene can transform an organism and express that gene
Provide evidence that bacteria can take in foreign DNA in the form of a plasmid
Reinforce the following process:
DNA ? RNA ? Protein ? Trait
Observe how genes are regulated
3. Applications of Genetic Transformation Used in many areas of Biotechnology
Agriculture (pests, frost, & drought)
Bacteria (oil spills)
Gene therapy (sick cells into healthy cells)
Medicine (produce insulin & hormones)
4. Key Terms to Know DNA: Plasmid
Bacteria: E. coli (strain: HB101K-12)
Growth media: LB Broth (Luria & Bertani)
Ampicillin: Antibiotic kills bacteria “amp”
Arabinose: Sugar source for energy & carbon
Heat shock Process that increases permeability of the cell membrane to DNA
GFP: Green Fluorescent Protein (w/UV)
5. The Genes of Interest Ampicillin resistance
Gene regulation proteins-activate the GFP gene when arabinose is present
GFP: Green Fluorescent Protein
-originally isolated from the jellyfish:
Aequorea victoria
6. Chapters 18 & 19 Bacteria
Viruses & Operon Systems
7. Key Topics and Text Pgs to Review Topic Pgs.
Bacteria: Genetic recombination 346-350
Plasmids & Conjugation
Transformation (Lab #8)
Transposons: 351-352
Lac Operon System 353-356
Regulating Gene Expression
Viruses: DNA, RNA (retroviruses) 338-342
Lytic & Lysogenic Cycle 337-339
8. Relative size Differences between of Viruses, Prokaryotes, and Eukaryotes
9. Bacterial Reproduction of DNA
10. Transformation Uptake of foreign DNA from the environment
What we did in our lab (pGLO plasmid)
Requires unique cell-surface proteins on the that can recognize similar strands of DNA, bind to it, and allow uptake.
11. Conjugation and the transfer of the F Plasmid
12. Transduction
13. Detecting Genetic Recombination in Bacteria
14. Expected Results
15. Introductory Questions # Briefly explain the differences between Transformation, Conjugation, and Transduction. How are these three processes the same? (pgs. 348-349)
How is an “F plasmid” different from an “R plasmid”?
What are transposable elements and what do they do?
16. Introductory Questions # Name the two scientists that discovered the Lac operon system.
How are repressible operons different from inducible operons? Give an example of each.
What is the difference between an operator and a promoter?
Name three example of a virus that has DNA as its genetic material and three examples of Viruses with RNA as its genetic material.
Briefly explain what a vaccine is and what it does.
17. Insertion Sequences & Transposable Elements Always a part of of chromosomal or plasmid DNA
Sometimes called “jumping genes”-never detach
A single gene for coded for: transposase
Inverted sequences are on each side of an insertion sequences. Observed in bacteria only.
See pg. 352
Specialized plasmids are constructed using these sequences.
18. Jacob & Monod Discovered Lac Operon
Nobel Prize for Discovering Control of Gene Expression
19. Regulation of a Metabolic Pathway
20. Specialized Genes Operator = "on/off" switch for operon
Regulator = makes repressors to turn off an entire operon
Repressor = Binds to operator, turn off gene expression
Inducer = Joins with an active repressor, inactivates it
Co-repressor = Joins with inactive repressor, converts it to active
21. OPERON THEORY Operon = group of structural genes regulated as a unit
Several genes controlled by an operator site
22. Operon Complex RNA Polymerase must bind to the promoter site and continue past the operator site to transcribe mRNA
23. INDUCIBLE Operons Usually “OFF” - to turn ON:
INDUCER needs to bind to an active repressor and inactivate it
RNA Polymerase can then bind and transcribe mRNA
Ex. Lac operon is an inducible operon
24. Inactive Repressor-Lactose Present
25. Lac Operon Summary Beta-Galactosidase can then be made
26. Repressible Operons Usually “ON” - to turn OFF:
Co-repressor needs to bind to an inactive repressor and activate it
RNA Polymerase then cannot bind and transcribe mRNA
Ex. trp operon is a repressible operon: -trancription is usually on
-inhibited only by tryptophan (corepressor)
27. Inactive Repressor-Tryptophan Absent
28. Classic Example of Theory Splitting of a disaccharide LACTOSE molecule within E. coli (Lac Operon)
TWO molecules needed to bind to promotor site to induce transcription of lactose-splitting beta-galactosidase
One molecule = complex of cyclic AMP (cAMP) & cyclic AMP binding protein (CAP)
One molecule = RNA polymerase
29. Lac Operon Lactose ONLY used when glucose is not present in large quantities
When glucose is present, cAMP levels are low, cAMP cannot bind to CAP and initiate enzyme production
30. Lac Operon In absence of glucose, cAMP levels are HIGH, binding to CAP can occur
Beta-Galactosidase is made
31. Lac Operon RNA polymerase only binds efficiently when cAMP-CAP complex is in place
Lac Operon = an INDUCIBLE Operon
Lactose = an INDUCER
Binds to repressor and inactivates it
32. Operons Inducible (lac operon):
lactose metabolism
lactose not present: repressor active
operon off
no transcription for lactose enzymes
lactose present: repressor inactive operon on
inducer molecule inactivates protein repressor (allolactose)
transcription is stimulated when inducer binds to a regulatory protein
34. Lytic & Lysogenic Cycles of a Virus(Lysogenic:host is not destroyed)
35. 5 Classes of Viruses-Pg. 340
36. Examples of Common Viruses DNA RNA
Herpesvirus Ebola
Poxvirus Infuenza
Papovirus (warts) HIV
Measels, Mumps
Rabies
West Nile
37. HIV Infection (pgs 340-342)
38. HIV infection on a White Blood Cell
41. Lac Operon Summary Beta-Galactosidase can then be made
42. Key Concepts for Chapter 19 Oncogenes & Proto-Oncogenes 370-373
Tumor Supressor Genes
McClintok’s transposons 375-376
43. Introductory Questions # Why are transposons called “jumping genes”? What purpose do the insertion sequences play?
What is the difference between an oncogene and a tumor repressor gene?
44. Molecular Biology of Cancer Oncogene •cancer-causing genes
Proto-oncogene •normal cellular genes
How? 1-movement of DNA; chromosome fragments that have rejoined incorrectly 2-amplification; increases the number of copies of proto-oncogenes 3-proto-oncogene point mutation; protein product more active or more resistant to degradation
Tumor-suppressor genes •changes in genes that prevent uncontrolled cell growth (cancer growth stimulated by the absence of suppression)