Download 1-2 Teacher

13-1 Changing the Living World
Slide
1 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Selective Breeding
What is the purpose of selective
breeding?
Slide
2 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
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.
Slide
3 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Selective Breeding
Humans use selective breeding to pass
desired traits on to the next generation
of organisms.
Slide
4 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Selective Breeding
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.
=
+
Slide
5 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Selective Breeding
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.
Slide
6 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Slide
7 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Increasing Variation
Increasing Variation
Why might breeders try to induce
mutations?
Slide
8 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Increasing Variation
Breeders increase the genetic variation
in a population by inducing mutations.
Slide
9 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Increasing Variation
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.
Slide
10 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
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.
Slide
11 of 18
Copyright Pearson Prentice Hall
End Show
13-1 Changing the Living World
Increasing Variation
Producing New Kinds of Plants
Mutations in some plant cells produce cells that
have double or triple the normal number of
chromosomes.
This condition, known as polyploidy, produces new
species of plants that are often larger and stronger
than their diploid relatives.
Polyploidy in animals is usually fatal.
Except in the case of the Red Viscacha Rat
Slide
12 of 18
Copyright Pearson Prentice Hall
End Show
13-1
Click to Launch:
Continue to:
- or -
Slide
13 of 18
End Show
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.
Slide
14 of 18
End Show
Copyright Pearson Prentice Hall
13-1
Crossing a plant that has good diseaseresistance with a plant that has a good foodproducing capacity is an example of
a. inbreeding.
b. hybridization.
c. polyploidy.
d. crossing over.
Slide
15 of 18
End Show
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.
Slide
16 of 18
End Show
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.
Slide
17 of 18
End Show
Copyright Pearson Prentice Hall
13-1
Increasing variation by inducing mutations is
particularly useful with
a. animals.
b. bacteria.
c. plants.
d. fungi.
Slide
18 of 18
End Show
Copyright Pearson Prentice Hall
END OF SECTION
Biology
Biology
Slide
20 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Slide
21 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
The Tools of Molecular Biology
How do scientists make changes to DNA?
Slide
22 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Scientists use their knowledge of the
structure of DNA and its chemical
properties to study and change DNA
molecules.
Slide
23 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
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
Slide
24 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
In genetic engineering, biologists make changes
in the DNA code of a living organism.
Slide
25 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
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.
Slide
26 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
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.
Slide
27 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
28 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
A restriction enzyme will cut a DNA sequence only if
it matches the sequence precisely.
Recognition sequences
DNA sequence
Restriction enzyme EcoR I cuts
the DNA into fragments
Sticky end
Slide
29 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Separating DNA
In gel electrophoresis, DNA fragments are placed
at one end of a porous gel, and an electric voltage
is applied to the gel.
When the power is turned on, the negativelycharged DNA molecules move toward the positive
end of the gel.
Whoa! We did this!!!!!!
Slide
30 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
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.
Slide
31 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
32 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
33 of 32
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Power
source
An electric voltage is
applied to the gel.
This moves the DNA
fragments across the
gel.
The smaller the DNA
fragment, the faster
and farther it will
move across the gel.
Gel Electrophoresis
Slide
34 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
The Tools of Molecular Biology
Based on size, the
DNA fragments make a
pattern of bands on the
gel.
These bands can then
be compared with
other samples of DNA.
Longer
fragments
Shorter
fragments
Gel Electrophoresis
Slide
35 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
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.
Slide
36 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
Reading the Sequence
In DNA sequencing, a complementary DNA strand
is made using a small proportion of fluorescently
labeled nucleotides.
Slide
37 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
DNA
Sequencing
Using the DNA Sequence
DNA strand with
unknown base
sequence
Dye molecules
DNA fragments
synthesized
using unknown
strand as a
template
Slide
38 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
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.
Slide
39 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
Base sequence
as “read” from
the order of the
dye bands on
the gel from
bottom to top:
TGCAC
Electrophoresis gel
Slide
40 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
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.
Slide
41 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
These enzymes also make it possible to take a gene
from one organism and attach it to the DNA of
another organism.
Such DNA molecules are sometimes called
recombinant DNA.
Slide
42 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
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.
Slide
43 of 32
Copyright Pearson Prentice Hall
End Show
13-2 Manipulating DNA
Using the DNA Sequence
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.
• PCR song:
http://www.youtube.com/watch?v=7uafUVNkuzg
• DNA Song: http://www.youtube.com/watch?v=bF2QalUj1Y
Slide
44 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
45 of 32
Copyright Pearson Prentice Hall
End Show
13-2
Click to Launch:
Continue to:
- or -
Slide
46 of 32
End Show
Copyright Pearson Prentice Hall
13-2
Restriction enzymes are used to
a. extract DNA.
b. cut DNA.
c. separate DNA.
d. replicate DNA.
Slide
47 of 32
End Show
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.
Slide
48 of 32
End Show
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.
Slide
49 of 32
End Show
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.
Slide
50 of 32
End Show
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.
Slide
51 of 32
End Show
Copyright Pearson Prentice Hall
END OF SECTION