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Copyright Pearson Prentice Hall
13-3 Cell Transformation
Recombinant DNA
Host Cell DNA
Target gene
Modified Host Cell DNA
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Bacteria
During transformation, a cell takes in DNA
from outside the cell. The external DNA
becomes a component of the cell's DNA.
Transforming Bacteria
Foreign DNA is first joined to a small, circular
DNA molecule known as a plasmid, which are
found naturally in some bacteria and have been
very useful for DNA transfer.
The plasmid has a genetic marker—a gene that
makes it possible to distinguish bacteria that
carry the plasmid (and the foreign
DNA) from those that don't.
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Bacteria
Recombinant
DNA
Gene for human
growth hormone
Gene for human
growth hormone
Human Cell
Bacteria cell
Bacterial
chromosome
Plasmid
Sticky
ends
DNA
recombination
Bacteria cell
containing gene
for human growth
hormone
DNA
insertion
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Plant Cells
Transforming Plant Cells
If transformation is successful, the
recombinant DNA is integrated into one of the
chromosomes of the cell.
In nature, a bacterium exists that produces
tumors in plant cells.
Researchers can inactivate the tumor-producing
gene found in this bacterium and insert a piece of
foreign DNA into the plasmid.
The recombinant plasmid can then be used to
infect plant cells.
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Plant Cells
When their cell walls are removed, plant cells in
culture will sometimes take up DNA on their own.
DNA can also be injected directly into some cells.
Cells transformed by either procedure can be
cultured to produce adult plants.
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Plant Cells
Complete plant
generated from
transformed cell.
Inside plant cell,
Agrobacterium
inserts part of its
DNA into host
cell
chromosome.
Plant cell
colonies Transformed bacteria
introduce plasmids into
plant cells.
Agrobacterium
tumefaciens
Cellular
DNA
Gene to be
transferred
Recombinant
plasmid
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Animal Cells
Transforming Animal Cells
Many egg cells are large enough that DNA can be
directly injected into the nucleus.
Enzymes may help to insert the foreign DNA into
the chromosomes of the injected cell.
DNA molecules used for transformation of animal
and plant cells contain marker genes.
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Animal Cells
DNA molecules can be constructed with two ends
that will sometimes recombine with specific
sequences in the host chromosome.
The host gene normally found between those two
sequences may be lost or replaced with a new gene.
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
Transforming Animal Cells
Recombinant DNA
Modified Host Cell DNA
Target gene
Flanking sequences
match host
Recombinant DNA
replaces target gene
13-3 Cell Transformation
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Copyright Pearson Prentice Hall
13-3 Cell Transformation
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Engineering Bacteria
http://www.teachersdomain.org/asset/biot11_vid_genengdna/
Bacterial Transformation
http://www.teachersdomain.org/asset/biot11_vid_transbact/
Library of Genetic Engineering Video
http://www.teachersdomain.org/browse/?fq_hierarchy=k12.sci.life.gen
.engineering
Documentary on Gen Modified Foods
http://www.youtube.com/watch?v=Bx3vu7fd2n8
Copyright Pearson Prentice Hall
- or -
Continue to: Click to Launch:
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Copyright Pearson Prentice Hall
13-3
Slide
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Copyright Pearson Prentice Hall
13-3
Plasmids can be used to transform
a. bacteria only.
b. plant cells only.
c. plant, animal, and bacterial cells.
d. animal cells only.
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Copyright Pearson Prentice Hall
13-3
An unknowing pioneer in the concept of cell
transformation was
a. Luther Burbank.
b. Frederick Griffith.
c. Oswald Avery.
d. James Watson.
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Copyright Pearson Prentice Hall
13-3
One reason plasmids are useful in cell
transformation is that they
a. are found in all types of cells.
b. prevent gene replication.
c. counteract the presence of foreign DNA.
d. have genetic markers indicating their
presence.
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Copyright Pearson Prentice Hall
13-3
A common method of determining whether bacteria have taken in a recombinant plasmid containing a gene for resistance is to
a. introduce them into plant cells.
b. introduce them into animal cells.
c. treat them with an antibiotic.
d. mix them with other bacteria that do not have the plasmid.
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Copyright Pearson Prentice Hall
13-3
Successful transformation of an animal or a plant cell involves
a. the integration of recombinant DNA into the cell’s chromosome.
b. changing the cell’s chromosomes into plasmids.
c. treating the cell with antibiotics.
d. destroying the cell wall in advance.