Download 13-2 Manipulating DNA

Manipulating DNA
Slide
1 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Scientists use knowledge of the structure
and function of DNA to manipulate it.
Slide
2 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Techniques:
• extract DNA from cells
• cut it into smaller pieces
• identify the sequence of bases in it
• make unlimited copies of it
Slide
3 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
DNA Extraction
The cells are broken open and the DNA is
separated from the other molecules.
Slide
4 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Cutting DNA
DNA is cut into smaller fragments using restriction
enzymes.
Slide
5 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Each restriction enzyme cuts DNA at a specific
sequence of nucleotides.
Recognition sequences
DNA sequence
Restriction enzyme EcoR I cuts
the DNA into fragments
Sticky end
Slide
6 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Separating DNA - gel electrophoresis
DNA fragments are placed at one end of a porous
gel and an electric voltage is applied.
The negatively-charged DNA molecules move
toward the positive end of the gel.
Slide
7 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Power
source
DNA plus restriction
enzyme
Longer
fragments
Mixture of
DNA
fragments
Gel
Gel Electrophoresis
Copyright Pearson Prentice Hall
Shorter
fragments
Slide
8 of 32
End Show
13-2 Manipulating DNA
First, restriction
enzymes cut DNA into
fragments.
The Tools of Molecular Biology
DNA plus
restriction enzyme
The DNA fragments
are poured into wells
on a gel.
Mixture of DNA
fragments
Gel Electrophoresis
Copyright Pearson Prentice Hall
Gel
Slide
9 of 32
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Power
source
An electric voltage is
applied to the gel.
DNA fragments move
across the gel.
Smaller fragments
move faster and
farther.
Gel Electrophoresis
Slide
10 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
DNA fragments make a
pattern of bands.
These bands can then
be compared with
other samples of DNA.
Longer
fragments
Shorter
fragments
Gel Electrophoresis
Slide
11 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
Cutting and Pasting
Enzymes that splice DNA together make it possible
to take a gene from one organism and attach it to the
DNA of another.
Such DNA molecules are called Recombinant DNA.
Slide
12 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
Making Copies
Polymerase chain reaction (PCR) allows
biologists to make copies of genes.
-DNA is heated to separate its two strands.
-Primers bind to the single-stranded DNA.
-DNA polymerase makes copies of the DNA
Slide
13 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
Polymerase Chain Reaction (PCR)
DNA heated to
separate strands
DNA polymerase adds
complementary strand
DNA fragment
to be copied
PCR cycles 1
DNA copies 1
2
2
3
4
4
8
5 etc.
16 etc.
Slide
14 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cell Transformation
Recombinant DNA
Host Cell DNA
Target gene
Modified Host Cell DNA
Slide
15 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transforming Bacteria
Transforming Bacteria
A cell takes in DNA from outside the cell.
Foreign DNA is first joined to a small, circular DNA
molecule in bacteria known as a plasmid.
Slide
16 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transforming Bacteria
Recombinant
DNA
Gene for human
growth hormone
Gene for human
growth hormone
Human Cell
Bacterial
chromosome
DNA
Sticky
ends
recombination
DNA
insertion
Bacteria cell
Plasmid
Bacteria cell
containing gene
for human growth
hormone
Copyright Pearson Prentice Hall
Slide
17 of 32
End Show
13-2 Manipulating DNA
Transforming Plant Cells
Transforming Plant Cells
• A bacterium exists that produces tumors in plants.
• Researchers can inactivate the tumor gene and
insert a piece of foreign DNA into the plasmid.
• The recombinant plasmid can then be used to
infect plant cells.
Slide
18 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Gene to be
transferred
Transforming Plant Cells
Agrobacterium
tumefaciens
Inside plant cell,
Agrobacterium
inserts part of its
DNA into host
cell
chromosome.
Cellular
DNA
Recombinant
plasmid
Plant cell
colonies
Transformed bacteria
introduce plasmids into
plant Copyright
cells.
Pearson Prentice Hall
Complete plant
generated from
transformed cell.
Slide
19 of 32
End Show
13-2 Manipulating DNA
Transforming Animal Cells
Transforming Animal Cells
• DNA can be directly injected into the nucleus of
an egg cell.
• Enzymes insert the foreign DNA into the
chromosomes of the injected cell.
Slide
20 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transforming Animal Cells
Recombinant DNA
Recombinant DNA
Flanking sequences
match host
replaces target gene
Target gene
Modified Host Cell DNA
Slide
21 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Applications of
Biotechnology
Transgenic Organisms
• Contains genes from other species.
Slide
22 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transgenic Organisms
Transgenic Microorganisms
• Transgenic bacteria produce important
substances useful for health and industry.
• insulin
• growth hormone
• clotting factor
Slide
23 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transgenic Organisms
Transgenic Animals
• Transgenic animals have been used to improve
the food supply.
• Mice have been produced with human genes that
make their immune systems act similarly to ours.
• This allows scientists to study the effects of
diseases on the human immune system.
Slide
24 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Transgenic Organisms
Transgenic Plants
• Transgenic plants are now an important part of
our food supply.
• Many of these plants contain a gene that
produces a natural insecticide, so plants don’t
have to be sprayed with pesticides.
Slide
25 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Dolly and Bonnie
Cloning
• A clone is a member
of a population of
genetically identical
cells produced from a
single cell.
• In 1997, Ian Wilmut
cloned a sheep called
Dolly.
Slide
26 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Donor Nucleus
Fused cell
Egg Cell
Embryo
Cloned
Lamb
Foster Mother
Copyright Pearson Prentice Hall
Slide
27 of 32
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
28 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
29 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
30 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
31 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
32 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Cloning
Cloning Dolly
Slide
33 of 32
Copyright Pearson Prentice Hall
End Show