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Chapter 9Biotechnology

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DNA Extraction0Why would we want to extract DNA?

0Use chemicals to break down cell membrane/wall and nucleus.0The DNA is now free to be extracted

0DNA is sticky, and can be easily pulled out of a mixture. 0This is called “spooling” DNA

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“Spooled” DNA

0Extracted DNA

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Restriction Enzymes0After DNA has been extracted, restriction enzymes are added0Cut DNA at VERY SPECIFIC sites

0 Specific nucleotide sequence0 Makes large DNA molecules more manageable and easier to study. 0 Cuts it up into smaller sections.

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Restriction enzymes

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Gel electrophoresis0An electrical current is used to separate a

mixture of DNA fragments from each other. 0Fragments are sorted by size.

0The smaller the fragment, the further it moves. 0DNA moves towards positive end of gel.0DNA is negatively charged because of the

phosphate0Positive and negative attract.

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Gel Electrophoresis

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DNA fingerprinting0 There is a 1 in

5.4million chance that someone could have the same DNA as you. 0What are some of the

ways that we use DNA fingerprinting today?

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Cloning0A clone is a genetically identical copy of a gene or an

organism0Asexual Reproduction = 100% identical0Example: Plants clone themselves0Example: Bacteria and binary fission = split into 2 0Example: Sea star re-growing lost limbs

(regeneration)

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CloningCloning “Dolly” 19970A body cell is taken from a

donor who is going to be cloned.

0An unfertilized egg is taken from another individual and the nucleus is removed.

0The nucleus of the body cell is fused with the unnucleated egg cell to create an embryo.

0The embryo is then stimulated to begin dividing.

0Embryo is implanted into a surrogate mother.

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Positive and negative of cloning.

Positive Negative

0organs for transplant into humans

0 save endangered species

0Higher crop yields

0 Cloning raises concerns.

0 low success rate0 clones “imperfect”

and less healthy than original animal

0 decreased biodiversity

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Why aren't the cloned cats exactly identical?

0Environment has an affect on gene expression

0Why?

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Transgenic/Recombinant DNA

0Plasmid – tiny rings of DNA found in bacteria 0A transgenic organism is one that has one or more

genes from another organism inserted into its genome. 0Genetically modified organism (GMO)

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Transgenic organisms:Genetically engineered crops

0Resistant to frost, disease and insects0Smaller amount of pesticides needed to

protect plant0More and bigger plants produced

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Human Genome Project

0Started in 19900Research effort to sequence all of human DNA 046 chromosomes

0Over 3.3 billion nucleotides0Mapping every gene location (loci)0Conducted by scientists around the world

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Gene Therapy0The replacement of a defective or missing gene, or the

replacement of a new gene, into a person’s genome to treat a disease.

0First successful gene therapy took place in 19900Much of gene therapy is still experimental0Researchers are studying many different methods to treat

cancer0 Gene to stimulate persons immune system to attack cancer cells0 Insert “suicide” gene into cancer cells.