Ch. 13 Genetic Engineering

Restriction Enzymes Cuts DNA at a specific sequence of nucleotides.

Gel Electrophoresis Making a DNA fingerprint. Cut DNA into specific fragments using restriction enzymes. Place in wells in agarose gel. DNA is negative. DNA goes to positive end in chamber. Dye the gel. Result a unique fingerprint.

Using DNA sequence Knowing the sequence allows researchers to study specific genes. Discover the functions of different genes and gene combinations. Scientists can add dyed bases to strands of DNA then the sequence can be determined.

Cutting and Pasting DNA synthesizers – synthetic sequences can then be joined to “natural” ones using enzymes that splice DNA together. Recombinant DNA – combining DNA from different sources.

Polymerase Chain Reaction http://www.youtube.com/watch?v=_YgXcJ4n-kQ Making many copies of DNA. Primers are added, DNA complementary sequence that marks where the DNA will be copied. DNA is heated to separate the two strands. Then cooled to allow the primers to bind to single-stranded DNA. DNA polymerase starts making copies of the region between the primers. A few cycles can produce millions of copies.

13-3 Cell Transformation A cell takes in DNA from outside the cell. This external DNA becomes a component of the cell’s DNA. Bacteria can be transformed simply by placing them in a solution containing DNA molecules. (Griffith’s Exp.)

Transforming Bacteria Plasmid – circular DNA found in bacteria. Contains a DNA sequence that promotes plasmid replication.

Plasmid Genetic Marker A gene that makes it possible to distinguish bacteria that carry the plasmid (and the foreign DNA) from those that don’t. Ex. Genes for resistance to antibiotics, compounds that can kill bacteria…

Transforming Plant Cells Scientists have found they can inactivate genes in plasmids. Foreign DNA is injected into cells and is incorporated into the DNA.