recombinant dna host cell dna target gene modified host

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13-3 Cell Transformation

Recombinant DNA

Host Cell DNA

Target gene

Modified Host Cell DNA

13-3 Cell Transformation

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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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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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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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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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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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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.

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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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Transforming Animal Cells

Recombinant DNA

Modified Host Cell DNA

Target gene

Flanking sequences

match host

Recombinant DNA

replaces target gene

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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

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Continue to: Click to Launch:

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13-3

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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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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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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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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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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.