1. NOTES - CH 15 (and 14.3): DNA Technology (“Biotech”)

2. “TRADITIONAL” BIOTECH: -microorganisms to make wine / cheese
BIOTECHNOLOGY: the use of living organisms or their components to do practical tasks
“TRADITIONAL” BIOTECH:
-microorganisms to make wine / cheese
-selective breeding of livestock
-production of antibiotics

3. **Practical goal of biotech = improvement of human health and food production

4. DNA Technologies: 1) Making a recombinant DNA molecule;
2) Gene therapy;
3) DNA fingerprinting;
4) Cloning.

5. Recombinant DNA: Combining fragments of DNA from different sources;
Result: organisms with their DNA + foreign DNA…such organisms are known as: TRANSGENIC ORGANISMS.

7. Example of transgenic organism:
 Tobacco plant that contains a gene from a firefly – it glows!

8. BIOLUMINESCENT CAT!

9. “Toolkit” for recombinant DNA technology involves:
-restriction enzymes
-DNA vectors
-host organisms

10. RESTRICTION ENZYMES = enzymes that recognize and cut short, specific DNA sequences

11. Restriction Enzymes…
are used to cut out a specific DNA fragment from an organism’s genome;
recognize sequences that are “palindromic” (the same letters backward and forward);
 typically cut sequences in a “staggered” manner so that the two ends of the fragments are single-stranded;

13. Restriction Enzymes (cont.)…
 this creates “sticky ends” so that the DNA fragment from one organism will be complementary to the DNA fragment from another organism. (complementary base pairing)

14. Gene Splicing:
GENE SPLICING = rejoining of DNA fragments after cutting with restriction enzymes – foreign DNA is recombined into a bacterial plasmid or viral DNA

18. VECTORS = carriers for moving DNA from test tubes back into cells
-bacterial plasmids (small, circular DNA molecules that replicate within bacterial cells)
-viruses

19. HOST ORGANISMS:
bacteria are commonly
used as hosts in genetic
engineering because:
 bacterial cells are simple, and grow quickly, replicating and expressing any foreign genes they carry.

20. Gene Cloning:
Once the foreign DNA has been transferred into the host bacterial cell, it replicates every time the cell divides;
CLONES = genetically identical copies of a gene

22. Gene Expression:
In addition to copying the introduced foreign gene, bacterial cells will also EXPRESS the genes (make the protein the gene encodes!)
EXAMPLE: if the gene for human insulin is inserted into a bacterial
plasmid and then into a
host bacterial cell, that cell
will start to make
HUMAN INSULIN!

23. Steps Involved in Cloning a Human Gene:
1)  Isolate human gene to clone;
2) Isolate plasmid from bacterial cell;
3) Add a restriction enzyme to cut out human gene & add same R.E. to open up bacterial plasmid (creates complementary “sticky ends”);
4) Combine human gene with bacterial plasmid;
plasmid
Human gene

24. Cloning a Human Gene (cont.)…
5) Insert recombinant DNA plasmid back into bacterial cell;
6) As bacterial cell reproduces, it makes copies of the desired gene…and expresses that gene (makes whatever protein the gene encodes)!

26. Applications of DNA Technology:
Recombinant bacteria in industry;
Recombinant bacteria in medicine;
Recombinant bacteria in agriculture;
Transgenic animals;
Transgenic plants.

27. Recombinant bacteria in industry:
Bacteria that can:
 break down pollutants;
 degrade oil spills;
 extract minerals from ores.

28. Recombinant bacteria in medicine:
Bacteria that have received human genes and produce:
 human growth hormone;
 insulin to treat
diabetes;
 the amino acid
phenylalanine.

30. Recombinant bacteria in agriculture:
Bacteria that:
 protect crops against frost;
 produce natural fertilizers;
 prevent crops from spoiling after harvest.

31. Transgenic animals:
Engineer / produce animals with human diseases so that they can be studied in detail.

32. Transgenic plants: Plants that are engineered to:  resist herbicides;
 produce internal pesticides;
 increase protein production.

34. Other DNA Technologies:
Polymerase Chain Reaction (PCR);
Human Genome Project;
Gel Electrophoresis;
Gene Therapy;
DNA Fingerprinting

36. The Polymerase Chain Reaction (PCR)
 allows any piece of DNA to be quickly copied many times in the lab;

37. PCR (continued)…
BILLIONS of copies of DNA are produced in just a few hours (enough to use for testing);
In 6 cycles of PCR:
cycle 1: 2 copies
cycle 2: 4 copies
cycle 3: 8 copies
cycle 4: 16 copies
cycle 5: 32 copies
cycle 6: 64 copies
cycle 20: 1,048,576!!

38. Polymerase Chain Reaction (PCR)
PCR is highly specific; only a small sequence is amplified
 only tiny amounts of DNA are needed.

39. Starting materials for PCR:
DNA to be copied
Nucleotides (A,G,C,T)
Primers
DNA polymerase

42. Applications of PCR: analyze DNA from tiny amounts of
tissue or semen found at crime scene;
 analyze DNA from single embryonic cells for prenatal diagnosis;
 analyze DNA or viral genes from cells infected with difficult to detect viruses such as HIV;
 used extensively in Human Genome Project (14.3)

44. PCR works
like a
copying
machine for
DNA!
                                                                                                                                                   

45. Analysis of Cloned DNA: Gel electrophoresis
  separates DNA molecules based on SIZE
 a mixture of DNA fragments will be sorted into bands, each consisting of DNA molecules of the same length
YOUR DNA
MY DNA

47. Steps Involved in DNA Fingerprinting:
1)  Collect DNA from a sample;
2) Perform PCR if necessary to make more DNA;
3) Cut DNA apart using RE’s
**Junk DNA (introns) will be cut at different places for different people, therefore producing different size fragments

48. DNA Fingerprinting (cont.)…
4)  Electrophoresis is used to separate DNA pieces on a gel to create a banding pattern;
5) Photo of DNA gel is taken as evidence;
6) Banding patterns can then be compared.

51. Sample 1
Sample 2
DNA_DetectivePC.exe

53. Gene Therapy:
GENE THERAPY = the insertion of normal genes into human cells to correct genetic disorders
Diseases treated include:
 cystic fibrosis
 SCID
(immune deficiency)

54. Biotech Today & Tomorrow
Experimental
Ethical issues
Research funding
Who can afford treatment?