For the bulk of class today we started the Genetic Engineering note packet. Here is what we got done today:
DNA Technology: methods to study and manipulate genetic material.
- Corn can produce its own insecticide.
- Bacteria can clean up pollution
- DNA fingerprints-to solve crimes. Anything that is cellular has a DNA fingerprint. It's not your fingerprint on your finger.
- Advances toward curing fatal genetic diseases. (Ethical Problems?)
Human Genome Project
- To sequence all DNA in the human genome
- To identify location and function of every gene.
- 2003-99% sequenced
- Hundreds of disease-associated genes identified
- Ex: Parkinson's Disease
4 Ways DNA Technology Can be Used
- Use of recombinant (recombined or changed) DNA to produce useful products.
- Use of DNA fingerprinting in forensic science
- Comparison of genomes
- Use of human gene therapy for treatment of diseases
3 Ways to Transfer DNA
- Transformation-the taking up of DNA from the fluid surrounding a cell. Ex: 1920's-Griffith-a harmless strain of bacteria took up pieces of DNA left from dead cells of a disease-causing strain.
- Transduction-the transfer of bacterial genes by a plasmid (circular piece of DNA in bacteria). The phage (virus) has a fragment of DNA from its previous host cell (a stowaway). Now it is injected into the new host.
- Conjugation-a "male" bacterial cell attaches to a "female" cell by sex pilli, a bridge forms, and DNA passes from the "male" to the "female."
- Once DNA gets into a bacterial cell, by whatever method, it can integrate into recipient's chromosome, replacing part of the original DNA
- Some plasmids can transfer a copy of themselves to another cell by conjugation
Recombinant DNA Technology-lab techniques for combining genes from different sources & species into a single DNA molecule.
- Biotechnology-the use of organisms to perform practical tasks
- Ex: Use of bacteria to produce cancer drugs & pesticides
- Ex: Transfer of genes into plants and farm animals
More on biotechnology
- Genetically modified organism (GM or GMO)=an organism that carries recombinant DNA
- Transgenic organism=a host that carries DNA from a different species
- Through biotechnology-can make Humulin, human insulin, made in bacteria. 1st recombinant DNA drug for human use in 1982.
- Genentech Biotech Co.-knew amino acid sequence of the human insulin protein. Put the DNA sequence together, inserted them into E. Coli cells. Bacteria cranked out large quantities of insulin.
- Produced in fermentation vats, 4 stories high, 24 hrs/day.
- 4mill.+ people with diabetes use this.
- Human Growth Hormone-used to come from human cadavers (dead people). Now grown in transgenic bacteria.
- Erythropoietin (EPO)-mammalian cells grow this protein, a treatment for anemia. (Anemia is when you have blood with low amounts of iron in it)
- For vaccines-genetically engineered cells make large amounts of the antigen on the pathogen. Ex: Yeast produces a vaccine against hepatitis B, a liver disease.
- In 2002 1/2 of American crops of soybeans and corn were genetically modified
- Corn-resists attack from European corn borer
- Strawberries-bacterial proteins act as natural antifreeze
- Potatoes-provide cholera immunity
- Golden rice-with beta-carotene which body uses to make Vitamin A
- Transgenic sheep-carry human gene in milk, used for treatment of cystic fibrosis
- No transgenic animals used in food supply yet. Ideas: Leaner meat, faster maturing cow, larger muscles on cattle.
- Ethical problems? Safety problems?
Recombinant DNA Techniques
- use bacterial plasmids: they are small and readily taken up by bacterial cells. Act as vectors, carriers that move genes from one cell to another. Replicates any foreign DNA that has been inserted.
HW Tonight: UP pages 7-10, try pages 13-15. MEET IN SCIENCE COMPUTER LAB TOMORROW.
Next scribe: Jimmy