Chapter 13 Genetic Engineering

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14 Δεκ 2012 (πριν από 4 χρόνια και 11 μήνες)

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Chapter 13 Genetic Engineering


Selective Breeding
-

choosing what parents you
want to produce offspring for the next
generation.


What do get when you cross a bull dog and a
shitzu?


Hybridization
-

Crossing dissimilar individuals to
bring together the best of both organisms.


Hybrid Vigor
-

phenomenon, offspring are better
than the parents.


Inbreeding is the continued breeding of
individuals with similar characteristics.


Risky, because it could bring out the
recessive alleles and cause a genetic defect.

Blindness, joint problems

Increase Variation


Why would humans want to increase
variations?


Better the species


Make the mutation occur faster


More variety


http://www.techapps.net/interactives/pepp
erMoths.swf


Manipulating DNA


Scientist change DNA by


Extracting DNA from cells


Cut into smaller pieces


Identify the sequence of bases on the DNA
molecule


Make unlimitied copies of DNA

DNA Extraction


Cells are opened up and DNA is
separated from other parts of the cell

Cutting DNA


DNA is cut into small fragments by
restriction enzymes. (Cuts DNA at a
specific nucleotide sequence…very
precise)

Separating DNA


Gel Electrophoresis
-

DNA Fragments are
placed in certain gel wells and an electric
voltage is passed through them.


DNA molecules move toward the opposite
end of the gel.


Smaller DNA fragments move faster
through the gel.

Using the DNA Sequence


The DNA Sequence can be read, studied,
or changed.


Compare genes with other organisms.


Recombinant DNA
-

produced by
combining DNA from different sources.

Making Copies


In order to study genes, it helps to make
copies.


PCR (Polymerase Chain Reaction)
-

makes many copies of DNA through a
process of heating and cooling using DNA
polymerase.

13.4 Applications of Genetic
Engineering


Transgenic Organisms
-

organisms contain
genes from other organisms.


Example: The enzyme (luciferase) from fire
flies was transferred into a tobacco plant cell.


What do you think happens?


The plant glows at dark…page 331



Why make transgenic organisms?


Resist pests, herbicides, harsh conditions


Improve nutritional value, shelf life


Test and study


Medical purposes…insulin, growth
hormone, clotting factors


Transgenic Animals can produce more
milk, less fat, human proteins

Cloning


Cloning is producing genetically identical
cells from a single cell.


Bacteria is easy to clone (unicellular)


What about multicellular organisms?


Ian Wilmut cloned the first sheep. DOLLY.


Cloning Process

To Clone or Not to Clone?