SL Biology Unit #6 Biotech PCR DNA Profiling DNA Extraction Transgenic Bacteria Animal Cell Transformation Restriction Enzymes Gel Electrophoresis Transgenic Plants Cloning

DNA Extraction Place cells in detergent to break down membranes and salt to remove the histone proteins on the DNA Place cell extract in ethanol DNA is insoluble in ethanol, so it comes out of solution, and can be removed for study

Polymerase Chain Reaction (PCR) Takes a small amount of DNA, and makes many copies of it The more DNA available, the more studies you can do with it Frequently used for small amounts of DNA left at crime scenes

Polymerase Chain Reaction (PCR) The DNA fragment to be copied is heated to make the strands separate. Enzyme DNA polymerase adds new complementary strands to each old strand. The process is then repeated over and over.

DNA Profiling Just as no two people have the same fingerprint, no two people (except identical twins) have same DNA.

DNA Profiling Differences between individuals are due to different sequences of nucleotide bases Remember, different alleles are result of differences in base sequences Ex: AACTGGCA vs. AACCGGCA

Restriction Enzymes A restriction enzyme is an enzyme that cuts DNA into small fragments. The size of the fragments depends on the person’s DNA sequence. Therefore, you get different sized fragments from different individuals.

Gel Electrophoresis Gel electrophoresis is a way of separating, by size, the DNA fragments produced by restriction enzyme cuts

Gel Electrophoresis DNA fragments placed into wells in gel slab Electric voltage is applied to gel. DNA (negatively charged) migrates to (+) end of gel. Smaller the fragment, faster and farther it moves.

Transgenic Bacteria Genes for human proteins like insulin and blood clotting factor can be inserted into bacteria Bacteria then translate the inserted gene to produce the protein it codes for Proteins can be used to treat people with disorders like diabetes or hemophilia

Transgenic Bacteria

Transgenic Plants Plants can be transformed with genes from other organisms to: Help plants resist pests Help plants resist weed-killing chemicals Give plants additional nutrient value

Transgenic Plants Process uses a bacteria that infects plants and causes tumors Tumor-causing gene is removed, and another gene of choice is inserted

Animal Cell Transformation Uses: Insert human genes into experimental animals (mice) to study the gene function Create livestock that grow faster, produce leaner meat, resist disease better.

Animal Cell Transformation DNA to be inserted is injected directly into fertilized egg. Cell enzymes that usually repair DNA or help in recombination insert the new DNA into the animal’s chromosomes.

What is cloning?

Cloning to Create a New Individual Genetically Identical to an Existing Organism

Cloning to Create a New Individual Genetically Identical to an Existing Organism