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Learn about the use of organisms to perform practical tasks for humans, such as manipulating DNA and engineering bacteria. Discover the applications and controversies of genetically modified organisms.
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13.1 What is biotechnology? The use of organisms to perform practical tasks for humans
13.1 Biologists Manipulate DNA • Today, we mainly manipulate the genomes of organisms. • We called this act of manipulation DNA technology.
13.1 Bacteria – Commonly used in Biotechnology * because they can acquire new genes in many ways! 1.Tunnel-like structure forms between 2 bacteria so DNA can be passed-Conjugation 2. Transformation – bacteria can “take up” free floating DNA into their own DNA 3. Viruses can carry bacterial genes from one bacteria to another- transduction.
13.1 Recombinant DNA Technology Definition - technology involving the combining of DNA and/or genes from different sources (even genes from different species). Uses of DNA technology: • Make more nutritious crops (ex. Corn) • Make medicine in large quantities • Help us understand specifically how gene sequences work
13.2 Engineering Bacteria • Bacteria contain plasmids • Plasmids are small circular pieces of DNA separate from the bacterial chromosome. • Plasmids carry genes
13.2 Plasmids • Scientists can manipulate plasmids to make them useful to us and Bacteria can transfer plasmids!! • Example: • Insert a gene to make a medicine into a plasmid • Put the plasmid into bacteria • When the bacteria reproduce they make many copies of the medicine!
13.2 How Do They Do It??? Restriction Enzyme=scissors • Cut • Use restriction enzymes to cut the desired DNA/gene out of a larger chromosome • Paste • Put the desired DNA/gene fragment into a plasmid • Put the plasmid into a bacterium • As the bacterium reproduces it makes many copies of the desired gene!! (Page 270 Case Study)
13.2 Genomic Library & Nucleic Acid Probes • Genomic Library: the complete collection of cloned DNA fragments from an organism • Nucleic Acid Probe: complimentary nucleotides labeled with a radioactive isotope used to “tag” single strand of a DNA sequence of choice.
13.2 FYI: Useful Products Using Genetic Engineering • Bacteria make chemicals that clean up hazardous spills and toxic waste sites • Bacteria are mass-producing useful chemicals like pesticides and therapeutic drugs • Pigs & Cattle make human insulin hormone in their milk for people with diabetes • Recombinant DNA technology is used to develop Vaccines – Hepatitis B (viral proteins are massed produced in yeast cells then used in vaccines)
13.3 Genetically Modified Organisms • A genetically modified organism (GMO) is any organism that has acquired any genes artificially. • If a species is called TRANSGENIC if it has foreign genetic material from a different species.
Just a few…GMO FOODS • Honey • Cotton • Tomatoes • Corn • Vegetable Oil • Peas • Potatoes
Warm-Up - In Groups… • ½ the class will use their books to compile a list of postive or good reasons/outcomes of using genetically modified organisms (plants and animals) • ½ the class will use their books to make a list of negative or unwanted reasons to use genetically modified organisms.
13.3 Genetically ModifiedPlants • Over 50% of soybean and corn crops were genetically modified in some way! • Most common genetic modifications: • Genes for herbicide resistance • Genes to resist insect and fungi pests
13.3 Genetically Modified Animals • Goals for GMO animals… • Produce mass quantities of hormones (insulin) • Get animals to market quicker (salmon) • Breed animals with better quality products (sheep wool) • FUN!! $$$$$$$
13.3 The GMO Controversy Although studies to date have shown that eating genetically modified foods have no negative health affects…people continue to demand stricter regulations. Major Concern: GMO food can pose unknown health risk…request strict labeling laws **”ORGANIC CRAZE”**
13.4 DNA Tech Has Many Applications • PCR or Polymerase Chain Reaction technique can mass produce specific sequences of DNA without the use of living cells • Takes less time than use of living cells • Requires less amount of desired DNA initially • Used for cloning rare DNA & ID small amounts of infectious DNA (AIDS) Thermocycler- machine used for PCR
13.4 PCR Technique“make a lot of DNA” from a small sample Page 278 figure 13-15
13.4 Gel Electrophoresis • Used when you want to compare DNA from different sources. • Produces “banding patterns” which can be compared and analyzed.
13.4 Comparing DNA: How it works! (Pg 279) 1.Different DNA samples are cut into “fragments” by restriction enzymes Smaller DNA fragments move further Each sample produces different banding patterns in the gel so they are easily compared 2.DNA “fragments” move through gel using electric current.
13.4 Comparing DNA: Genetic Markers • Genetic Markers: are particular streches of DN that are variable among individuals. • Can be used to ID carriers of certain diseases
13.4 Comparing DNA: DNA Fingerprint • Just like every person has their own unique fingerprint…everyone has a unique banding pattern produced by their restriction fragments in gel electrophoresis. • 97% of our DNA is “junk” or non-coding and is extremely different from any other persons “junk” DNA. • Forensics!!
13.4 Who committed the crime? Suspect # 1 2 3 4 5 6 7 Bloodstain evidence from crime scene! Using PCR and Gel Electrophoresis, a DNA fingerprint can be made from a single drop of blood or from a hair follicle. DNA is extracted from a small sample and multiple copies are made using PCR Gel Electrophoresis of unique genetic markers are compared
13.5 Stem Cells and Homeotic Genes • Stem cells – cells (early in development) that remain undifferentiated and have the potential to be any type of cell. • Homeotic Genes – genes that control development of specific locations in organisms.
Cloning • To make a clone: • A donor cell is fused with an egg cell • The fused cell begins to divide normally to form an embryo • Embryo is placed in uterus of foster mom • Clone is born
