Transcript 2.1 Chemistry`s Building Block: The Atom

15.1 Biotechnology = Genetic Engineering
Adding, deleting, or transplanting genes from one organism
to another, to alter the organisms in as a means of meeting
societal needs.
• Agriculture
• Human health
• Criminal justice
15.2 Transgenic Biotechnology
• Transgenic organism: an organism whose
genome has stably incorporated one or more
genes from another species.
• DNA from one organism put into another
• Example: Human gene in a bacterial cell
• Human insulin is produced within a
bacterium
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Insulin from cows and pigs until…
1982 –biotech revolution
Chop out human DNA sequence for
production of insulin
Insert into E. coli
Grow cells that make human insulin
Produced efficiently - huge quantities
1st genetically engineered drug approved by the
Food and Drug Administration
Other important examples
1. Human growth hormone (HGH)
-dwarfism
- Weight loss in AIDS pts
2. Erythropoietin (EPO)
-Production of red blood cells
-Illnesses & treatments that lead to
anemia
Biotechnology – Human Health: The
treatment of diseases and production of
medicines are improved with biotechnology
 Prevent
 Cure
diseases
diseases
 Treating
diseases
• The treatment of diabetes
Gene Therapy for SCID (severe
combined immunodeficiency disease)
Immune system can’t
properly make a type of
white blood cell
- caused by a bad gene
Vulnerable to most infections
Usually leads to death within
the first year of life
“Bubble Boy”
Gene Therapy for SCID
- Remove cells from bone
marrow (stem cells - ability to
develop into any cell type)
- Infect stem cells with
transgenic virus carrying a
working copy of the gene
- Put cells back in patient
- Pt cells should produce
normal white blood cells,
permanently curing disease.
- Worked in 14 out of 16
cases
Restriction Enzymes: proteins derived
from bacteria that can cut DNA in specific places.
1. A portion of a
DNA strand, highlighted
here, has the recognition
sequence GGATCC.
“sticky ends”
DNA fragment
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2. A restriction enzyme
moves along the DNA
strand until it reaches
the recognition sequence
and makes a cut between
adjacent G nucleotides.
3. A second restriction
enzyme makes another
cut in the strand at the
same recognition
sequence, resulting in a
DNA fragment.
Figure 15.3
Plasmids
bacterium
• small, extrachromosomal rings
of bacterial DNA
that can exist
outside of bacterial
cells and that can
move into these
cells through the
process of
transformation
bacterial
chromosome
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plasmid
Figure 15.4
human cell containing
gene of interest
bacterium
plasmid
bacterial
DNA
chromosome
protein
synthesis
Use same restriction
enzyme to snip
plasmid.
human protein
of interest
1. Use restriction enzymes
to snip gene of interest
from the isolated human
genome.
recombinant DNA
2. Insert gene into plasmid
(complementary sticky ends
will fit together).
transformation
3. Transfer the plasmid back
into bacterial cell.
4. Let bacterial cells replicate.
Harvest and purify the
human protein produced
by the plasmids inside
the bacterial cells.
replication
bacterial
clones
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Figure 15.5
Getting Human Genes into Plasmids
• Recombinant DNA: 2 or more segments of
DNA that have been combined by humans into
a sequence that does not exist in nature.
• Cloning vector: self-replicating agent that
functions in the transfer of genetic material.
• Viruses known as bacteriophages are another
common cloning vector.
• Yeast, hamster cells, & mammals
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Real-World Transgenic Biology
• Transgenic food crops are planted in
abundance today in the United States.
• GMOs
• Genetically modified organisms
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Selective Breeding
• Used for thousands of
years
• Taking the crops with
best traits and breeding
with other optimal
traits
• Can take years
• Now, genes can be
taken and put into the
crops
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More Nutritious Crops
• Low Vit A = blindness
• Beta Carotene helps
make Vit A
• Rice is grown with a
gene for beta carotene
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Resistance
• Crops can be given
genes that help them
resist pest-killing
treatments
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Faster Growing and Money Saving
Organisms
• Salmon that can grow in
half the time
• Chickens without
feathers were grown to
save time and money
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Fears and risks:
Are genetically modified foods safe?
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GMO Fears
#1: Organisms that we want to kill may become
invincible.
 #2: Organisms that we don’t want to kill may be
killed inadvertently.
 #3: Genetically modified crops are not tested or
regulated adequately.
 #4: Eating genetically modified foods is dangerous.
 #5: Loss of genetic diversity among crop plants is
risky.
 #6: Hidden costs may reduce the financial
advantages of genetically modified crops.

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Almost everyone in the United States consumes
genetically modified foods regularly without
knowing it.
What foods are responsible for this?
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15.3 Reproductive Cloning
• “Dolly” the sheep
• Somatic Cell
Nuclear Transfer
• Controversial
What is a clone?
• A genetically identical copy of a biological entity
• Genes, cells, plants
• Reproductive cloning is the process of making
adult clones of mammals of a defined genotype.
• Dolly the sheep was a reproductive clone.
• Other mammals have been cloned since then
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Somatic Cell Nuclear Transfer
(SCNT)
• Egg cell has nucleus removed and is fused
with an adult cell containing a nucleus and,
therefore, DNA.
• The fused cell then starts to develop as an
embryo and is implanted in a surrogate
mother.
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white
sheep
udder
cells
black-faced
sheep
1. A cell was taken from the udder of a
six-year-old white sheep and then allowed
to divide many times in the laboratory.
Meanwhile an egg was taken from a
black-faced sheep.
egg cell
(nucleus
removed)
DNA
3. The donor cell and egg were put next to
each other, and an electric current was
applied to the egg cell.
4. This caused the two cells to fuse and
prompted an activation that reprogrammed
the donor-cell DNA. This caused the fused
cell to start developing as an embryo.
embryo
surrogate
mother
2. One of the resulting udder cells was
selected to be the “donor” cell for the
cloning. Meanwhile, using a slender tube
called a micropipette, researchers sucked
the DNA out of the egg.
Dolly
5. After some incubation, the embryo was
implanted in a third sheep, which served as
the surrogate mother.
6. This mother gave birth to Dolly the sheep,
which grew into an adult.
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Figure 15.8
Reproductive Cloning
• Reproductive cloning can work in tandem
with various recombinant DNA processes to
produce adult mammals possessing special
traits.
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Human Cloning
• Human clone - genetic replica of the person
who provided the donor-DNA cell
• genetically identical in the same way that
identical twins are
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15.4 Cell Reprogramming
• Two promising methods exist for generating
human cells that are needed to treat victims
of accident or disease:
• Production through embryonic stem cells
• Production through induced pluripotent stem
cells
• Both methods use the reprogramming of
cells to yield desired cell types.
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Cell Fates: Committed or Not?
• Most cells in the adult human body have
undergone commitment
• a developmental process that results in cells
whose roles are completely determined
• Most muscle cells have undergone commitment
• Can give rise to nothing but muscle cells
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What is a Stem Cell?
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Embryonic Stem Cells
fertilization
days 1–3
day 5
inner
cell mass
blastocyst
Cells from the blastocyst’s inner cell mass, known
as embryonic stem cells (ESCs), can give rise to
all the different cell types in the adult human body.
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Figure 15.9
Adult Stem Cells
• Not the same as ESC
• Demonstrated some ability to differentiate
into various types of cells
• Do not have the differentiation potential of
ESCs, nor the same ability to replicate
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Obtaining ASCs is difficult
• Where they exist
 Where we can obtain them
• All of the 60+ distinct organs of
the human body

Bone Marrow

Umbilical Cord Blood

Placental Tissue

Adipose (fat) Tissue
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Induced Pluripotent Stem Cells
• 2007 – researchers developed a type of
human stem cell not derived from an
embryo: the iPSC
• Appear to have all the developmental power
of ESC
• Potentially fewer issues with tissue rejection
in medical transplantation procedures
• Widely used as a means of studying human
disease
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Induced Pluripotent Stem Cells (iPSCs)
• Induced
Pluripotent Stem
Cells – adult cells
that are “reset” to
behave like an
ESC
• From almost any
tissue – biopsy
http://learn.genetics.utah.edu/content/stemcells/quickref/
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Potential uses of stem cells
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15.5 Forensic Biotechnology
• Forensic DNA typing: use of DNA to
establish identities in connection with legal
matters
• Identities of criminals, biological fathers, and
disaster victims
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The Use of PCR
• Polymerase chain reaction (PCR):
technique for quickly producing many
copies of a segment of DNA
• Useful in situations, such as crime
investigations, in which a large amount of
DNA is needed for analysis, yet the starting
quantity of DNA is small.
https://youtu.be/q-40l8nmsis
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1. A researcher selects a
DNA region of interest.
double-stranded
DNA
2. The DNA is heated, causing
the two strands of the double
helix to separate.
single-stranded
DNA
primers
double-stranded
DNA
3. As the mixture cools, short DNA
sequences called primers form
base pairs with complementary
DNA sequences on their
respective strands.
4. DNA polymerase goes down
the line, synthesizing
complementary DNA
strands. The end result is a
doubling of the original DNA.
5. The process is repeated
many times, doubling the
amount of DNA each time.
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Figure 15.11
15.6 Controversies in Biotechnology
• Biotech progress also comes slowly because so
many of the processes it is developing are not
just new, but controversial.
• A notable biotech controversy concerns
genetically modified (GM) crops or GMOs.
• Opponents of genetically modified crops are
concerned about their effect on human health
and the environment.
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Controversies in Biotechnology
• There is no evidence so far that GM crops have
had detrimental effects in either area.
• But, consumer resistance to the crops has
sharply limited both the types being planted and
the types being put into development.
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Controversies in Biotechnology
• Some biotech controversies are essentially
ethical in nature.
• Among these are the controversies concerning
embryonic stem cells and therapeutic cloning.
• A more general controversy has to do with the
question of what level of constraint society
ought to impose on the modification of living
things.
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What’s everyone so afraid of?
Designer babies
- select for eye color
- select for height
- select for gender
What are the limits?
HW
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Three Parent IVF
- What is it?
- Who would use it?
- Why is it controversial?
HW
https://youtu.be/jQxsW_H5qr4
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