CH 17 - BIOTECHNOLOGY

     I. RECOMBINATION  = DNA MANIPULATION   

            -Inserting/mixing the genes of 1 organism with another. 

            -Same or different organisms

     II. GENETIC ENGINEERING/SPLICING - "Man-Made"

                  A. RESTRICTION ENZYMES/ENDONUCLEASES (p. 328)

                        1. Hundreds known

                        2. Protect bacteria from viral infection

                        3. Cuts foreign DNA or RNA at specific sites

                        4. Example:               G A A T T C               G                     A A T T C

                                                            C T T A A G  C T T A A                      G     

                        5. Leaves "sticky" ends (unmatched bases).

            6. These sticky ends can then be spliced together.

            7. Gel electrophoresis separates DNA fragments (p. 329)

      B. 3 WAYS RECOMBINATION OCCURS NATURALLY

            1. Transformation – Bacteria (indirect transfer)

                  a. PLASMIDS (p. 331)

                        1. Small circular piece of DNA from a bacteria. 

                                    2. Separate from chromosome – “dispensible”

                                    3. Small - only 2-30 genes.

                                    4. Often 100's per cell.

                              b. Transformation

                                    i. Cells release plasmids/DNA to envt

                                    ii. DNA is taken up by other cells (same or different)

                                    iii. Combined with the existing DNA to acquire "new" genes

                        2. Conjugation – Bacteria

                              a. Direct transfer of copy of plasmid from one cell to another.

                              b. Bacterial "sex" 

                              c. F-plasmid (fertility)

                              d. R-plasmid (antibiotic resistance)

            3. Sex - Eukaryotic, during crossing over of Prophase I in meiosis. 

                  C. 4 STEPS OF GENETIC ENGINEERING - Humulin/Insulin

                        1. CLEAVAGE Bacterial chromosome (DNA) is cut open by a restriction enzyme.

                              Same R.E. used to cut out a segment of human DNA with gene.

                        2. RECOMBINATION via transformation - human DNA picked up by bacteria

                              & “sticky ends” spliced together. Seal with ligase   

                        3. SCREENING - Find recombined gene.

                        4. CLONING - Culture & grow recombinant bacteria;

                              Turn on insulin gene, extract & purify.

                  D. MULTIPLE COPIES OF DNA - produce lots of DNA from a little

                        1. POLYMERASE CHAIN REACTION (p. 340)

                              a. Add DNA fragment, nucleotides, DNA polymerase & primer

                              b. Heat to open DNA fragment into 2 strands

                              c. As it cools, each strand is template for new strand = 2 copies

                              d. Repeat to get as many copies as you want!

                 III. APPLICATIONS - BIOTECHNOLOGY

                  A. GENETICS (Ch. 18 – GENOMICS)

1.    Gene sequencing - Human genome project = mapping genomes

2.    Proteomics - all proteins!

3.    BIOCHIPS - Diagnosis/detection/cause/location of defective gene

                                    Cure/treatment - experimental/difficult

                  B. MEDICAL

                        1. Produce rare/expensive drugs/chemicals/hormones

                              a. Interferon

                              b. Insulin - Humulin

                              c. Somatostatin - growth hormone (p. 344)

                        2. Vaccine production

                        3. Gene Therapy (p. 345)

                  C. AGRICULTURE = TRANSGENIC organisms (p. 346)

                        1. Resistance to drought, salt, fungal infestations & insects (p. 347)

                        2. Hybrids in 1 generation. . . no waiting for artificial selection

                              a. Golden rice (p. 348)

                  D. CLONING (p. 380 - 381)

                  E. STEM CELLS (p. 379)

                        1. Embryonic vs. adult

                  F. OTHERS

                        1. Fuel production (methane, gasoline, etc.)

                        2. Waste decomposition (oil, plastics, toxics, etc. . .)

                        3. Make snow.

                        4. Unlimited potential.

                  G. PROBLEMS (p. 383)

                        1. Moral & ethical questions - playing "God".

                        2. GM safety, loss of biodiversity,  bio & phys. containment (p. 348)

                        3. Patent rights to new life forms - inhibit flow of info. (p. 369)