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13–2 Manipulating DNA A. The Tools of Molecular Biology 1. DNA Extraction Homogenization: Cell walls, membranes, and nuclear material are broken Emulsification: Soap and enzymes break down membranes and emulsify lipids and proteins. Precipitation: Alcohol is layered on top of the solution. DNA is not soluble in alcohol and precipitates either in the alcohol or at the interface between the alcohol and the rest of the mixture. Collection: DNA can be pulled up from the interface or alcohol with a paper clip or glass rod. 13–2 Manipulating DNA 2. Cutting DNA “Restriction Enzymes” Cut DNA at precise locations, Cut a specific sequence of nucleotides 13–2 Manipulating DNA 2. Cutting DNA “Restriction Enzymes” Cut DNA at precise locations, Cut a specific sequence of nucleotides Recognition sequences DNA sequence Restriction enzyme EcoRI cuts the DNA into fragments. Sticky end 13–2 Manipulating DNA 2. Cutting DNA “Restriction Enzymes” Cut DNA at precise locations, Cut a specific sequence of nucleotides Recognition sequences DNA sequence Restriction enzyme EcoRI cuts the DNA into fragments. Sticky end 13–2 Manipulating DNA 3. Separating DNA DNA plus restriction enzyme Power source Longer fragments Mixture of DNA fragments Shorter fragments Gel Electrophoresis 13–2 Manipulating DNA B. Using the DNA Sequence 1. Reading the Sequence 2. Cutting and Pasting 3. Making Copies 13–2 B. Manipulating DNA Using the DNA Sequence 1. Reading the Sequence 2. Cutting and Pasting 3. Making Copies Fluorescent dye Single strand of DNA Strand broken after A p324 Power source Strand broken after C Strand broken after G Strand broken after T Gel 13–2 B. Manipulating DNA Using the DNA Sequence DNA polymerase adds complementary strand 1. Reading the Sequence 2. Cutting and Pasting DNA heated to 3. Making Copies separate strands DNA fragment to be copied p325 PCR cycles 1 DNA copies 1 2 2 3 4 5 etc. 4 8 16 etc. 13–2 B. Manipulating DNA Using the DNA Sequence DNA polymerase adds complementary strand 1. Reading the Sequence 2. Cutting and Pasting DNA heated to 3. Making Copies separate strands DNA fragment to be copied p325 PCR cycles 1 DNA copies 1 2 2 3 4 5 etc. 4 8 16 etc. 13–3 Cell Transformation Sneaking In You probably have heard of computer viruses. Once inside a computer, these programs follow their original instructions and override instructions already in the host computer. Scientists use small “packages” of DNA to sneak a new gene into a cell, much as a computer virus sneaks into a computer. 13–3 Cell Transformation Sneaking In 1. Computer viruses enter a computer attached to some other file. What are some ways that a file can be added to a computer’s memory? 2. Why would a person download a virus program? 3. If scientists want to get some DNA into a cell, such as a bacterial cell, to what sort of molecule might they attach the DNA? CELL TRANSFORMATION Essential Questions •What happens during cell transformation? •How can you tell if a transformation experiment has been successful? In 13.2 we talked about manipulating DNA How do we get it back into the cell? TRANSFORMATION- a cell takes in DNA from outside the cell. The DNA becomes part of the cell’s DNA REMEMBER - Griffith’s experiment TRANSFORMING BACTERIA In 13.2 we talked about manipulating DNA.How do we get it back into the cell? TRANSFORMATION- a cell takes in DNA from outside the cell. That DNA becomes part of the cell’s DNA REMEMBER - Griffith’s experiment Transforming Bacteria Foreign DNA attached to plasmid Plasmid - small circular piece of natural DNA •ensures DNA will be replicated •contains genetic marker such as resistance to antibiotic (cells that survive antibiotic Transforming Bacteria Plasmid - circular piece of bacterial DNA Recombinant DNA just has to be inserted into plasmid Transforming Bacteria Bacterial Transformation Restriction Enzymes: Proteins that cut the DNA in a specific place Recombinant Plasmid Bacterial Transformation Bacterial Transformation Section 13-3 Recombinant DNA Gene for human growth hormone Human Cell o to ction: Sticky ends Bacterial chromosome Plasmid Gene for human growth hormone Bacterial Transformation Section 13-3 Recombinant DNA Gene for human growth hormone Gene for human growth hormone Human Cell Bacterial Cell o to ction: Plasmid Sticky ends Bacterial chromosome DNA insertion Bacterial cell for containing gene for human growth hormone Transforming Bacteria Foreign DNA attached to plasmid Plasmid - small circular piece of natural DNA •ensures DNA will be replicated •contains genetic marker such as resistance to antibiotic (cells that survive antibiotic have been transformed) Transforming Plant Cells In nature, bacteria insert plasmids into plant cells and produce tumors Researchers disable tumor producing gene and introduce foreign DNA Bacteria insert the foreign DNA into the plant Transforming Plant Cells In nature bacteria insert plasmid into plant cells that produces tumors Researchers disable tumor producing gene and introduce foreign DNA Bacteria insert the foreign DNA into the plant QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Sometimes possible to remove cell wall and have plants take up DNA on their own If transformation is successful, the foreign DNA is integrated into one of the host’s chromosomes. If transformation is successful, the foreign DNA is integrated into one of the host’s chromosomes. Transforming Animal Cells Similar to plants Sometimes possible to inject DNA into egg cells Usually contain marker gene Recently developed techniques enable genes to, “knock out” host gene Transforming Animal Cells Similar to plants Sometimes possible to inject DNA into egg cells Usually contain marker gene Recently developed techniques enable genes to, “knock out” host gene QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. 13.4 Applications of Genetic Engineering •What are some examples of useful transgenic organisms? •What are the main steps involved in cloning? What are some examples of useful transgenic organisms? What are the main steps involved in cloning? Applications of Genetic Engineering In 13.2, we learned how DNA is manipulated In 13.3, we learned how foreign DNA is inserted into host cells Does this work between animals and plants? In 13.2, we learned how DNA is manipulated In 13.3 we learned how foreign DNA is inserted into host cells Does this work between animals and plants? Transgenic Organisms Contain genes from other organisms Spurred growth of Biotechnology Transgenic Microorganisms Important products •insulin •growth hormone Human genes inserted into bacteria Transgenic Microorganisms Important products •insulin •growth hormone Human genes inserted into bacteria Transgenic Animals Mice given human genes to study human immune system Livestock given genes for extra growth hormone Poultry given genes to resist infection Transgenic Animals Mice given human genes to study human immune system Livestock given genes for extra growth hormone Poultry given genes to resist infection Transgenic Plants Important part of food production NOW •52% of soybeans •25%of corn in US Built-in insecticides Built-in weed control A strain of rice with added vitamin A 13–4 Applications of Genetic Engineering Transgenic Organisms Sometimes DNA directly injected QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. “Knockout” genes A donor cell is taken from a sheep’s udder. Donor Nucleus These two cells are fused using an electric shock. Fused Cell Egg Cell The nucleus of the egg cell is removed. An egg cell is taken from an adult female sheep. Embryo Cloned Lamb The embryo develops normally into a lamb—Dolly Go to Section: The embryo is placed in the uterus of a foster mother. Foster Mother The fused cell begins dividing normally . 13–4 Applications of Genetic Engineering: Cloning A body cell is taken from a donor animal. An egg cell is taken from a donor animal. The nucleus is removed from the egg. The body cell and egg are fused by electric shock. The fused cell begins dividing, becoming an embryo. The embryo is implanted into the uterus of foster mother. The embryo develops into a cloned animal. 13–4 Video: Clone Age Copy these questions and use them to guide your note taking during the video 1. What is a clone? 2. Give some examples of plants and animals that have been cloned. 3. The video claims that there are human clones walking among us. Explain how this could be true. 4. Would a cloned human be the same as the human he or she was cloned from? Explain