3. Copyright Pearson Prentice Hall
Selective Breeding
Selective Breeding
Selective breeding allows only
those organisms with desired
characteristics to produce the
next generation.
Nearly all domestic animals and most
crop plants have been produced by
selective breeding.
5. Copyright Pearson Prentice Hall
Hybridization
Hybridization is the crossing of
dissimilar individuals to bring
together the best of both
organisms.
Hybrids, the individuals produced
by such crosses, are often hardier
than either of the parents.
6. Inbreeding
Inbreeding is the continued
breeding of individuals with
similar characteristics.
Inbreeding helps to ensure that the
characteristics that make each breed
unique will be preserved.
Serious genetic problems can
result from excessive
inbreeding.
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Breeders increase the
genetic variation in a
population by inducing
mutations.
8. Mutations occur spontaneously,
but breeders can increase the
mutation rate by using radiation
and chemicals.
Breeders can often produce
a few mutants with desirable
characteristics that are not
found in the original
population.
9. Copyright Pearson Prentice Hall
Increasing Variation
Producing New Kinds of Bacteria
Introducing mutations has allowed
scientists to develop hundreds of useful
bacterial strains, including bacteria that
can clean up oil spills.
10. Copyright Pearson Prentice Hall
Producing New Kinds of Plants
Polyploidy produces new species of
plants because the chromosome
number changes. Polyploids are
often larger
and stronger
than their
diploid relatives..
Polyploidy in
animals is
usually fatal.
12. Copyright Pearson Prentice Hall
Scientists use their knowledge of the
structure of DNA and its chemical
properties to study and change DNA
molecules.
13. Copyright Pearson Prentice Hall
Scientists use different
techniques to:
extract DNA from cells
cut DNA into smaller pieces
identify the sequence of bases in
a DNA molecule
make unlimited copies of DNA
14. Copyright Pearson Prentice Hall
In genetic engineering,
biologists make changes in the
DNA code of a living organism.
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DNA Extraction
DNA can be extracted from most
cells by a simple chemical
procedure.
The cells are opened and the
DNA is separated from the other
cell parts.
16. Copyright Pearson Prentice Hall
The Tools of Molecular Biology
Cutting DNA
Most DNA molecules are too
large to be analyzed, so
biologists cut them into smaller
fragments using restriction
enzymes.
17. Copyright Pearson Prentice Hall
Each restriction enzyme cuts DNA
at a specific sequence of
nucleotides.
Restriction enzyme EcoR I
cuts the DNA into fragments
Sticky end
Recognition sequences
DNA sequence
18. Copyright Pearson Prentice Hall
Recognition sequences
DNA sequence
Restriction enzyme EcoR I
cuts the DNA into fragments Sticky end
A restriction enzyme will cut a
DNA sequence only if it matches
the sequence precisely.
19. In gel electrophoresis, DNA
fragments are placed at one end of
a porous gel, and an electric
voltage is applied to the gel.
The negatively-charged
DNA molecules move
toward the positive end
of the gel.
20. Gel electrophoresis can be used to
compare the genomes of different
organisms or different individuals.
It can also be used to locate and
identify one particular gene in an
individual's genome.
22. Copyright Pearson Prentice Hall
1. restriction
enzymes cut
DNA into
fragments.
2. DNA
fragments
are poured
into wells on
a gel.
DNA plus
restriction
enzyme
Mixture of
DNA
fragments
Gel
23. Copyright Pearson Prentice Hall
The Tools of Molecular Biology
3. An electric
voltage moves
the DNA
fragments
across the gel.
The smaller the
DNA fragment,
the faster and
farther it will
travel.
Power
source
24. Copyright Pearson Prentice Hall
The Tools of Molecular Biology
4. The pattern
of bands can
be compared
with other
samples of
DNA.
Longer
fragments
Shorter
frag
ments
25. Copyright Pearson Prentice Hall
Using the DNA Sequence
Knowing the sequence of an organism’s
DNA allows researchers to study specific
genes, to compare them with the genes
of other organisms, and to try to discover
the functions of different genes and gene
combinations.
26. Copyright Pearson Prentice Hall
Reading the Sequence
In DNA sequencing, a
complementary DNA strand is
made using a small proportion of
fluorescently labeled
nucleotides.
27. Copyright Pearson Prentice Hall
Using the DNA Sequence
DNA
Sequencing
DNA strand
with
unknown
base
sequence
DNA
fragments
synthesized
using
unknown
strand as a
template
Dye
molecules
28. Copyright Pearson Prentice Hall
Each time a labeled nucleotide is added, it
stops the process of replication, producing
a short color-coded DNA fragment.
When the mixture of fragments is
separated on a gel, the DNA sequence can
be read.
29. Base sequence as
“read” from the
order of the dye
bands on the gel
from bottom to
top:
T G C A C
Electrophoresis gel
30. Cutting and Pasting
Short sequences of DNA can be
assembled using DNA synthesizers.
“Synthetic” sequences can be joined to
“natural” sequences using enzymes that
splice DNA together.
31. Copyright Pearson Prentice Hall
These enzymes also make it possible to
take a gene from one organism and attach
it to the DNA of another organism.
DNA molecules that contain genes
from more than one organism are
sometimes called recombinant
DNA.
32. Copyright Pearson Prentice Hall
Making Copies
Polymerase chain reaction (PCR)
is a technique that allows
biologists to make copies of
genes.
A biologist adds short pieces of DNA that
are complementary to portions of the
sequence.
33. DNA heated
to separate
strands
PCR cycles
DNA copies
1 2 3 4 5 etc.
1 2 4 8 16 etc.
Polymerase Chain Reaction (PCR)
DNA polymerase
adds complementary
strand
DNA
fragment
to be
copied
34. Copyright Pearson Prentice Hall
DNA is heated to separate its 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.
35. Copyright Pearson Prentice Hall
13-3 Cell Transformation
Recombinant DNA
Host Cell DNA
Target gene
Modified Host Cell DNA
36. Copyright Pearson Prentice Hall
During transformation, a bacteria
cell takes in DNA from outside the
cell. The foreign DNA becomes
inserted in the cell’s own DNA.
37. Copyright Pearson Prentice Hall
Foreign DNA is first joined to a
small, circular DNA molecule known
as a plasmid.
Plasmids are found naturally in some bacteria
and have been very useful for DNA transfer.
38. Copyright Pearson Prentice Hall
The plasmid has a genetic marker
—a gene that “marks” cells that
have successfully incorporated
the foreign DNA.
Ex. Production of identifiable protein,
antibiotic resistance.
39. Copyright Pearson Prentice Hall
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
Movie
40. Copyright Pearson Prentice Hall
Transformation in Plants
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.
Recombinant plasmids are used
to infect plant cells.
41. Copyright Pearson Prentice Hall
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.
TRANSFORMATION = taking in
foreign DNA
42. 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
Transformation
43. 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.
47. Copyright Pearson Prentice Hall
Transgenic bacteria can produce
large quantities of important
substances useful for health and
industry, including human proteins:
•insulin
•growth hormone
•clotting factor
48. Copyright Pearson Prentice Hall
Transgenic animals have been used to study
genes and to improve the food supply.
Mice have been produced with human genes
that make their immune systems act
similarly to those of humans.
This allows scientists to study the effects of
diseases on the human immune system.
49. Copyright Pearson Prentice Hall
Researchers are trying to produce
transgenic chickens that will be resistant
to the bacterial infections that can cause
food poisoning.
50. Copyright Pearson Prentice Hall
Transgenic plants are now an important
part of our food supply.
Many food plants contain a gene
that produces a natural
insecticide, so plants don’t have
to be sprayed with pesticides.
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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.
Dolly and Bonnie
59. Copyright Pearson Prentice Hall
Researchers hope cloning will enable them
to make copies of transgenic animals and
help save endangered species.
Studies suggest that cloned animals may
suffer from a number of genetic defects
and health problems.
60. Copyright Pearson Prentice Hall
13-1
The usual function of selective breeding is to
produce organisms that
a. are better suited to their natural environment.
b. have characteristics useful to humans.
c. can compete with other members of the
species that are not selected.
d. are genetically identical.
61. Copyright Pearson Prentice Hall
13-1
Crossing a plant that has good disease-
resistance with a plant that has a good food-
producing capacity is an example of
a. inbreeding.
b. hybridization.
c. polyploidy.
d. crossing over.
62. Copyright Pearson Prentice Hall
13-1
New species of plants that are larger and
stronger are a result of
a. monoploidy.
b. diploidy.
c. polyploidy.
d. triploidy.
63. Copyright Pearson Prentice Hall
13-1
The function of inbreeding is to produce
organisms that
a. are more genetically diverse.
b. are much healthier.
c. are genetically similar.
d. will not have mutations.
64. Copyright Pearson Prentice Hall
13-1
Increasing variation by inducing mutations is
particularly useful with
a. animals.
b. bacteria.
c. plants.
d. fungi.
65. Copyright Pearson Prentice Hall
13-2
Restriction enzymes are used to
a. extract DNA.
b. cut DNA.
c. separate DNA.
d. replicate DNA.
66. Copyright Pearson Prentice Hall
13-2
During gel electrophoresis, the smaller the DNA
fragment is, the
a. more slowly it moves.
b. heavier it is.
c. more quickly it moves.
d. darker it stains.
67. Copyright Pearson Prentice Hall
13-2
The DNA polymerase enzyme Kary Mullis found
in bacteria living in the hot springs of
Yellowstone National Park illustrates
a. genetic engineering.
b. the importance of biodiversity to
biotechnology.
c. the polymerase chain reaction.
d. selective breeding.
68. Copyright Pearson Prentice Hall
13-2
A particular restriction enzyme is used to
a. cut up DNA in random locations.
b. cut DNA at a specific nucleotide
sequence.
c. extract DNA from cells.
d. separate negatively charged DNA
molecules.
69. Copyright Pearson Prentice Hall
13-2
During gel electrophoresis, DNA fragments
become separated because
a. multiple copies of DNA are made.
b. recombinant DNA is formed.
c. DNA molecules are negatively
charged.
d. smaller DNA molecules move faster than
larger fragments.
70. 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.
71. 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.
72. 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.
73. Copyright Pearson Prentice Hall
13-3
A common method of determining whether
bacteria have taken in a recombinant plasmid 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.
74. 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.
75. Copyright Pearson Prentice Hall
13–4
Insulin-dependent diabetes can now be treated
with insulin produced through the use of
a. transgenic plants.
b. transgenic animals.
c. transgenic microorganisms.
d. transgenic fungi.
76. Copyright Pearson Prentice Hall
13–4
Transgenic tobacco plants that glow in the dark
were produced by transferring the gene for
luciferase from a
a. clone.
b. bacterium.
c. firefly.
d. jellyfish.
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13–4
The first mammal to be cloned was a
a. sheep.
b. horse.
c. dog.
d. cat.
78. Copyright Pearson Prentice Hall
13–4
In producing a cloned animal, an egg cell is
taken from a female and its nucleus is removed.
A body cell is taken from a male. The clone from
this experiment will
a. look just like the female.
b. be genetically identical to the male.
c. have a mixture of characteristics from both
animals.
d. resemble neither the male nor the
female.
79. Copyright Pearson Prentice Hall
13–4
Animals produced by cloning have been shown
to
a. all be perfectly healthy.
b. suffer from a number of health
problems.
c. live longer than uncloned animals.
d. be less intelligent than uncloned animals.