Transcript ppt_E4ch02_Biotechnology_2e

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Vitamin A deficiency can result in night
blindness and weakened immunity. It
affects over 250 million people each year.
I can’t see in
dim light.
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Our body can synthesize vitamin A from
beta-carotene.
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Scientists have successfully transferred
the genes for producing beta-carotene
from maize and bacteria to rice plants.
genes
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The resultant Golden Rice can produce
high levels of beta-carotene in its grains.
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A Swiss scientist developed transgenic golden rice rich in iron
and vitamin A, two major nutrient deficiencies in developing
countries where the major staple food is rice. This involved
genetically engineering 3 proteins and the vitamin precursor βcarotene from 4 different species.
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What are the advantages of genetic
engineering over traditional breeding in
crop improvement
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2.1 Biotechnology in medicine
Production of pharmaceutical
products
• human insulin
similar
processes
• human growth hormone
• vaccines
• monoclonal antibodies (單克隆抗體)
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2.1 Biotechnology in medicine
1 Human growth hormone (HGH)
• secreted from the pituitary gland
• important in development of
bones and muscles
• deficiency:
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2.1 Biotechnology in medicine
1 Human growth hormone (HGH)
• HGH was extracted from the pituitary
gland of dead people
 limited supply
 contaminated with pathogens
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2.1 Biotechnology in medicine
1 Human growth hormone (HGH)
• recombinant HGH
 unlimited amount
 pure
 low cost
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2.1 Biotechnology in medicine
1 Human growth hormone (HGH)
• bacteria are commonly used
- provide plasmids that act as vectors
- serve as host cells
- can be transformed easily
- can grow rapidly
- can grow in inexpensive culture media
- relatively stable culture
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2.1 Biotechnology in medicine
2 Vaccines
• antigenic proteins can be produced by
recombinant DNA technology
e.g. vaccines against hepatitis B
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2.1 Biotechnology in medicine
2 Vaccines
 Prepare a recombinant plasmid
gene for viral
surface protein
plasmid
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2.1 Biotechnology in medicine
2 Vaccines
 Introduce the recombinant plasmid
into a yeast cell
yeast cell
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2.1 Biotechnology in medicine
2 Vaccines
 Culture GM yeast on a large scale
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2.1 Biotechnology in medicine
2 Vaccines
 According to the genetic information
of the viral gene, the GM yeast
produces the viral surface protein
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2.1 Biotechnology in medicine
2 Vaccines
 The viral surface protein is collected
and purified for use
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2.1 Biotechnology in medicine
2 Vaccines
• traditional hepatitis B vaccines contain
the whole viruses
 viruses may become active and
infectious
• recombinant hepatitis B vaccines contain
only a viral surface protein
 safer to use
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Principle of Edible vaccine
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
• antibodies produced by the cell clones
derived from a single parent B cell
• highly specific
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"magic bullet" monoclonal antibody
1.
myeloma cells –
keeing dividing-immortal
2.
fuse with healthy
antibody-producing
B-cells
3.
Hybridomas
produced
4.
select hybridomas
cells with specific
antibodies
5.
Grow in culture
6.
Harvest monoclonal
antibodies
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
i) For diagnosis of diseases
• recognize the surface proteins of cancer
cells in tissue samples
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
ii) For developing sensitive tests
• home pregnancy tests
• bind to human chorionic gonadotrophin
(HCG) in urine
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Application of
monoclonal
antibodies:
Pregnancy
testing kit
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
iii) For isolating and purifying
important biological molecules
• specific to the molecule of interest
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
• Drawback of
monoclonal
antibodies
produced using B
cells from mice
 could stimulate an immune response
in humans
Results in their rapid removal from the blood, inflammatory
effects, and the production of human anti-mouse antibodies
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2.1 Biotechnology in medicine
In vitro / Recombinant Monoclonal antibodies:
Made by merging mouse DNA encoding the binding portion of a monoclonal antibody with
human antibody-producing DNA in living cells, and the expression of this hybrid DNA through
cell culture yielded partially mouse, partially human monoclonal antibody.
a human antibody with a small part of a mouse monoclonal antibody
 less likely to be destroyed in the human body
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2.1 Biotechnology in medicine
3 Monoclonal antibodies
• recombinant monoclonal antibodies
• used in the treatment of some forms
of cancer
- linked with a toxic drug
or a radioactive
substance –magic bullet
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2.1 Biotechnology in medicine
Gene therapy
• to treat a disease by supplementing the
defective gene with a normal gene
• vectors for transferring a normal gene
into a target cell
e.g. harmless viruses
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Diagram of the human chromosome set, showing the location of some genes whose
mutant forms can cause hereditary diseases. Conditions that can be diagnosed using
DNA analysis are indicated by a red dot.
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2.1 Biotechnology in medicine
Gene therapy
• ex vivo (先體外後體內) gene therapy:
cells are genetically modified outside the
body and then put back into the patient
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Gene therapy with a retrovirus
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2.1 Biotechnology in medicine
Gene therapy
• in vivo (體內) gene therapy:
cells are genetically modified inside the
body
vectors with
normal genes
direct transfer
of normal genes
into cells
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Cystic fibrosis (CF), the most common lethal, singlegene disorder affecting Northern Europeans and North Americans, is
caused by mutations in the cystic fibrosis transmembrane
conductance regulator (CFTR) gene.
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2.1 Biotechnology in medicine
Gene therapy
• germ line gene therapy (種系基因治療) :
corrects the genetic material of gametes
or zygotes
• genetic correction is inheritable
• done on animals only
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2.1 Biotechnology in medicine
Gene therapy
• somatic cell gene therapy (體細胞
基因治療) :
corrects the genetic material of somatic
cells
• genetic correction is not inheritable
• all human trials are of this type
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2.1 Biotechnology in medicine
Gene therapy
Potential benefits
• treat genetic diseases, cancer and
infectious diseases
• as a preventive measure against diseases
• correct a disease before it develops
and help remove all the defective
genes in the human population
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2.1 Biotechnology in medicine
Gene therapy
Potential hazards
• viral vectors cause diseases
• viral vectors cause severe immune
reactions
• insertion of new genes affects the
expression of existing genes
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2.1 Biotechnology in medicine
Gene therapy
Potential hazards
• new genes wrongly transported into non-target
cells, produce too much of the missing protein or
produce the protein at the wrong time
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Risks involved in gene therapy
• in an attempt experiment to treat
Ornithine transcarbamylase deficiency
by gene therapy, a patient died in 1999.
• The patient was injected with
adenoviruses carrying a corrected
gene in the hope that it would
manufacture the needed enzyme.
• He died four days later, apparently having
suffered a massive immune response
triggered by the use of the viral vector
used to transport the gene into his cells.
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Risks involved in gene therapy
• in an attempt experiment to treat
Ornithine transcarbamylase deficiency
by gene therapy, a patient died in 1999.
• The patient was injected with
adenoviruses carrying a corrected
gene in the hope that it would
manufacture the needed enzyme.
• He died four days later, apparently having
suffered a massive immune response
triggered by the use of the viral vector
used to transport the gene into his cells.
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Gene therapy poses
many ethical
.
and social questions
• tampering with human genes might lead to the
practice of eugenics, a deliberate effort to control
the genetic makeup of human populations.
• The most difficult ethical question is whether we
should treat human germ-line cells to correct the
defect in future generations.
• we will have to face the question of whether it is
advisable, under any circumstances, to alter the
genomes of human germ lines or embryos. Should
we interfere with human evolution in this way?
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2.1 Biotechnology in medicine
Stem cell therapy
•
•
•
•
•
unspecialized cells
unlimited mitotic cell division
can differentiate into different kinds of cells
Embryonic stem cells /Adult stem cells
Differs in their “potency”
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totipotent, pluripotent, multipotent?
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totipotent, pluripotent, multipotent?
• Totipotent cells can form all the cell types in a body,
plus the extraembryonic, or placental, cells. Embryonic
cells within the first couple of cell divisions (8-cell
stage) after fertilization are the only cells that are
totipotent.
• Pluripotent cells can give rise to all of the cell types that
make up the body. e.g. embryonic stem cells (16-cell
stage).
• Multipotent cells can develop into more than one cell
type, but are more limited than pluripotent cells; adult
stem cells and cord blood stem cells, peripheral blood
stem cells are considered multipotent.
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2.1 Biotechnology in medicine
Stem cell therapy
embryonic stem cells
• from blastocysts
• can differentiate into
almost any cell types
(Pluripotent)
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After fertilization, the zygote undergoes cleavage:
the first few mitotic divisions multiply the total number of cells without
increasing total mass.
The ball of cells that implants in the uterus is a blastocyst, and contains
the inner cell mass, where embryonic stem cells can be harvested.
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2.1 Biotechnology in medicine
Stem cell therapy
adult stem cells
• from childhood or
adult tissues like
bone
marrow, blood,
skeletal
muscles
• can only differentiate into a limited
range of cell types “Multipotent” or
unipotent
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2.1 Biotechnology in medicine
Stem cell therapy
• stem cells may be used to replace
damaged or abnormal cells in the
treatment of diseases
e.g. blood stem cells in bone marrow and in
peripheral blood, cord blood (臍帶血)
containing blood stem cells are used in the
treatment of blood diseases (multipotent)
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2.1 Biotechnology in medicine
Stem cell therapy
e.g. human embryonic stem cells
human
blastocyst
isolate embryonic
stem cells
cultured embryonic
stem cells
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2.1 Biotechnology in medicine
Stem cell therapy
e.g. human embryonic stem cells
induce the cells to differentiate
into specific cell types
insulin-producing cells
• for treating type 1 diabetes
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2.1 Biotechnology in medicine
Stem cell therapy
e.g. human embryonic stem cells
induce the cells to differentiate
into specific cell types
cardiac muscle cells
• for treating heart disease
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2.1 Biotechnology in medicine
Stem cell therapy
e.g. human embryonic stem cells
induce the cells to differentiate
into specific cell types
neurones
• for treating spinal cord injuries,
Parkinson’s disease
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Stem cell therapy / stem cell cloning
•
Since the
regrown cells
originate from
the patient,
there should be
no immune
rejection of the
transplanted
tissue.
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2.1 Biotechnology in medicine
Stem cell therapy
• isolation of embryonic stem cells
involves destruction of human embryos
 controversial
• adult stem cells occur in low number,
are difficult to isolate and can only
differentiate into a limited range of
cell types
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2.1 Biotechnology in medicine
Stem cell therapy
• human skin cells were successfully
re-programmed to become unspecialized
cells in 2007 – IPS cells
Nobel Prize in
physiology or
medicine (2012)
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2.1 Biotechnology in medicine
Stem cell therapy
• human skin cells were successfully
re-programmed to become unspecialized
cells in 2007 –IPS cells
 may act as a limitless source of
immune-compatible cells for
transplantation
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Sources of stem cells
(1) human embryos
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Sources of stem cells
(2) IPS – induced pluripotent stem cells
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Sources of stem cells
(2) IPS – induced pluripotent stem cells
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Applications of IPS cells
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2.1 Biotechnology in medicine
Stem cell therapy
• questions to be answered
How can we induce embryonic
stem cells to differentiate into
each of the desired cell types?
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2.1 Biotechnology in medicine
Stem cell therapy
• questions to be answered
How long can the transplanted
cells last in the body?
Are re-programmed cells safe to
use in therapy?
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2.1 Biotechnology in medicine
1 Some examples of pharmaceutical
products using biotechnology
include human insulin, human
growth hormone, vaccines and
monoclonal antibodies .
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2.1 Biotechnology in medicine
2 Monoclonal antibodies are
antibodies produced by the cell
clones derived from a single
parent B cell.
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2.1 Biotechnology in medicine
3
Gene therapy is to treat a disease
by supplementing the defective
gene with a normal gene.
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2.1 Biotechnology in medicine
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Germ line
gene therapy
Affects gametes
and zygotes
Genetic
correction is
inheritable
Somatic cell
gene therapy
Affects somatic
cells
Genetic
correction is not
inheritable
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2.1 Biotechnology in medicine
5 Potential benefits of gene therapy:
a It may treat genetic diseases,
cancer and infectious diseases.
b It may be used as a
preventive
measure against diseases.
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2.1 Biotechnology in medicine
5 Potential benefits of gene therapy:
c It may correct a disease before
the disease develops in the
individuals and help remove all
the defective genes in the
human population.
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2.1 Biotechnology in medicine
6 Potential hazards of gene therapy:
a Viral vectors may gain the ability
to cause diseases during
modification.
b Viral vectors may cause severe
immune reactions .
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2.1 Biotechnology in medicine
6 Potential hazards of gene therapy:
c The insertion of new genes
may affect the expression of
existing genes.
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2.1 Biotechnology in medicine
6 Potential hazards of gene therapy:
d The new genes may be wrongly
transported into non-target cells.
They may also produce too much
of the missing protein or produce
the protein at the wrong time. This
results in other health problems.
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2.1 Biotechnology in medicine
6 Potential hazards of gene therapy:
e The patient is repeatedly exposed
to possible hazards when
repeated gene therapy is
required.
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2.1 Biotechnology in medicine
7 Stem cells may be used in the
treatment of type 1 diabetes,
heart disease, muscular dystrophy,
spinal cord injuries, Parkinson’s
disease, etc.
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2.2 Biotechnology in agriculture
What are transgenic
organisms?
• organisms whose genetic material
has been altered through genetic
engineering
Golden Rice
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2.2 Biotechnology in agriculture
• transgenic organisms are
useful in scientific research
 for the study of gene functions
 as disease models
 for toxicity tests for new products
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2.2 Biotechnology in agriculture
Transgenic plants in agriculture
and the food industry
• many transgenic plants are major crops
maize (31%)
soya bean
(52%)
cotton (12%)
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canola (5%)
2.2 Biotechnology in agriculture
Transgenic plants in agriculture
and the food industry
• many transgenic plants are major crops
 for food use and as parents in
traditional breeding
• introduce genes for improving the yields
or nutritional value of crops
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2.2 Biotechnology in agriculture
1 Herbicide resistant soya beans and maize
• weeds can be killed by herbicide
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2.2 Biotechnology in agriculture
2 Pest resistant maize and cotton
• toxin is pest-specific
• reduces the use of chemical pesticides
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2.2 Biotechnology in agriculture
3 Disease resistant papayas
viral resistant
non-transgenic
• prevents crops from being damaged by
diseases
• reduces the use of chemical pesticides
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2.2 Biotechnology in agriculture
4 Rice, wheat and tomatoes tolerant to
cold, drought or high salinity of soil
• crops can be grown in winter, dry
climates and on saline lands
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2.2 Biotechnology in agriculture
5 Tomatoes with a longer shelf life
nontransgenic
transgenic
• reduces the loss of fruits
• fruits of better quality
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2.2 Biotechnology in agriculture
6 Soya beans, canola and rice with
improved nutritional value
• higher levels of ‘good’ lipids
help prevent heart disease
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2.2 Biotechnology in agriculture
6 Soya beans, canola and rice with
improved nutritional value
• higher levels of beta-carotene,
vitamin E, iron, zinc or lysine
prevent dietary deficiencies
Animation
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2.2 Biotechnology in agriculture
Transgenic animals in
agriculture and the food
industry
• introduce genes for improving the
productivity and quality of farm animals
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2.2 Biotechnology in agriculture
1 Fast-growing salmon
nontransgenic
transgenic
• decreases overfishing of wild salmon
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2.2 Biotechnology in agriculture
2 Cold resistant salmon
• expands the area for fish farming
3 Transgenic pigs that produce more
lean tissue and less fat
• improves human health
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2.2 Biotechnology in agriculture
4 Transgenic goats that produce milk with
improved composition and production
• produces lactose-free milk suitable for
people who cannot tolerate lactose
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2.2 Biotechnology in agriculture
4 Transgenic goats that produce milk with
improved composition and production
• produces milk with a lower level of ‘bad’
lipids which is healthier for the heart
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2.2 Biotechnology in agriculture
4 Transgenic goats that produce milk with
improved composition and production
• increases milk production
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2.2 Biotechnology in agriculture
5 Transgenic sheep that produce more
wool of better quality
• improves the quality of wool
• increases wool production
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2.2 Biotechnology in agriculture
6 Transgenic pigs that produce 60% less
phosphorus in their manure
• reduces pollution caused by manure
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2.2 Biotechnology in agriculture
1
Transgenic organisms are
organisms whose genetic material
has been altered through genetic
engineering.
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2.2 Biotechnology in agriculture
2 Uses of transgenic plants and
animals in scientific research:
a They are used for the study of
gene functions.
b They act as disease models.
c They are used for toxicity
tests for new products.
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2.2 Biotechnology in agriculture
3 Examples of desirable characteristics
built into transgenic plants:
• resistance to herbicides, pests
and diseases
• tolerance to cold , drought or
high salinity of soil
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2.2 Biotechnology in agriculture
3 Examples of desirable characteristics
built into transgenic plants:
• delayed softening or ripening
• improved nutritional value
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2.2 Biotechnology in agriculture
4 Examples of desirable characteristics
built into transgenic animals:
• faster growth
• cold resistance
• improved meat or milk
composition and production
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2.2 Biotechnology in agriculture
4 Examples of desirable characteristics
built into transgenic animals:
• improved wool quality and
production
• manure with low levels of
phosphorus
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2.2 Biotechnology in agriculture
5 Uses of transgenic plants and
animals in agriculture:
a Transgenic plants and animals
with improved productivity and
quality are produced. They may
provide a more reliable food
supply for all people.
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2.2 Biotechnology in agriculture
5 Uses of transgenic plants and
animals in agriculture:
b They can be used as
parents
in traditional breeding.
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2.2 Biotechnology in agriculture
5 Uses of transgenic plants and
animals in agriculture:
c They can help protect the
environment by reducing the
use of chemical pesticides or
producing less polluting manure .
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1
In addition to beta-carotene, what
other useful products can be produced
from genetic engineering?
Human insulin, human growth factor,
vaccines and monoclonal antibodies can
be produced from genetic engineering.
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2
What are the advantages of genetic
engineering over traditional breeding in
crop improvement?
Genetic engineering provides a quicker
and more precise method to modify the
genetic make-up and hence the
characteristics of crops.
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2
What are the advantages of genetic
engineering over traditional breeding in
crop improvement?
It also allows the transfer of new
characteristics from completely
non-related species.
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Biotechnology
applications in
medicine include
production of
gene
stem cell
pharmaceutical therapy therapy
products
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production of
pharmaceutical products
examples
human
insulin
vaccines
human growth
hormone
monoclonal
antibodies
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gene
therapy
divided into
germ line
gene therapy
somatic cell
gene therapy
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Biotechnology
used to produce
transgenic plants
and animals
used in agriculture
to improve
productivity
quality
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