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Genetic Mutations & Genetic Engineering Ch. 12-4 (pgs. 307-308) Ch. 13-2 thru 13-4 (pgs. 322-333)
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12-4 Mutations Mutations= Changes in genetic material 2 Types of mutations : Chromosomal and Gene Gene Mutations= Changes to the codons & genetic message Point Mutations: Caused by changes in one or a few nucleotides EX: substitutions, insertions or deletions
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12-4 Mutations Gene Mutations Cont… Frameshift Mutations: Occur from insertions or deletions because they shift the “reading frame” of the genetic message. They never occur from substitutions Chromosomal Mutations: Involve changes in the # or structure of chromosomes: EX: Inversions, duplications, deletions & translocations Some neither help nor harm, some are beneficial for genetic variation, some cause disorders and cancer
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13-2 Manipulating DNA Scientists have discovered how to use their knowledge of DNA to study & change DNA molecules EX: Extract DNA from cells, cut DNA into smaller pieces, identify sequence of bases in DNA, make unlimited copies of DNA
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13-2 Manipulating DNA Genetic Engineering: Making changes in the DNA code of a living organism. Occurs by: DNA Extraction: The cells are opened & DNA is separated from other cell parts Cutting DNA: Uses restrictions enzymes to cut specific sequences of nucleotides creating “sticky ends” that will match up with complimentary bases
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13-2 Manipulation DNA Restriction enzyme cutting DNA between Guanine & Adenine
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13-2 Manipulation DNA Separating DNA= Commonly done by gel electrophoresis. Electric volts applied to DNA cause negative DNA fragments to move to positive ends of the gel EX: 2 DNA samples showing identical bands of the same size and thickness show: same amount of DNA, fragments of the same size, the same DNA molecules Locates specific genes, compares genetic composition like paternity tests
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13-2 Manipulation DNA Knowing the sequence of an Organisms DNA allows scientists to study specific genes Reading DNA Sequences= Enzymes trigger DNA replication by adding nitrogenous bases (A,T,G,C) to an unknown single-stranded DNA template Uses fluorescent dyes to label the different nitrogenous bases & stop replication Uses nucleotide bases to trigger & stop replication Uses gel electrophoresis to show DNA bands
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13-2 Manipulating DNA Making Copies: Uses PCR (polymerase chain reaction). Triggers DNA replication by using complimentary “primers” added to single- stranded DNA molecule that scientist wants to copy DNA polymerase makes copies of the area between the two primers
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13-3 Cell Transformation Transformation: A cell takes in DNA from outside the cell Plasmid: Foreign DNA formed into a small circular DNA molecule. Used to incorporate foreign DNA into bacteria that will replicate allow it to be replicated Genetic Marker: Gene that makes it possible to distinguish bacteria that carry plasmids from those that don’t. EX: Gene for antibiotic resistance is used to select for bacteria that carry plasmids when that antibiotic is added
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13-3 Cell Transformation Transforming Plant Cells Can Occur 3 Ways: Use bacteria that are able to insert plasmids into the plant Remove plant cell walls so plasmid DNA is taken in by the nucleus Insert DNA directly into the cell
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Cell Transformation Transforming Animal Cells Can Occur By: DNA injected directly into the nucleus Enzymes help injected DNA become incorporated in the cell’s chromosomes Foreign DNA contains genetic markers that to determine which genes have been transformed
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13-4 Applications of Genetic Engineering Transgenic Organism: Organism that contains genes from other species Scientists use Genetic Engineering to make transgenic organisms
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13-4 Applications of Genetic Engineering Transgenic Microorganisms: bacteria transformed w/ human genes produce pharmaceutical compounds like insulin Transgenic Animals: Have been used to study how human genes function EX: Mice are created with human-like immune systems Transgenic Plants: Have been important to increasing the food supply. EX : Plants have genes that code for natural insecticides
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13-4 Applications of Genetic Engineering Clone: Member of a population of genetically identical cells produced from a single cell. EX: a bacterium taken from a bacterial colony First Mammal cloned was Dolly- a sheep cloned in Scotland in 1997
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