Transcript iGCSE Biology Section 5 lesson 2

IGCSE BIOLOGY
SECTION 5 LESSON 2
Content
Section 5
Uses of
biological
resources
a) Food production
b) Selective breeding
c) Genetic modification
(genetic engineering)
d) Cloning
Content
Lesson 2
b) Selective
breeding
c) Genetic
modification
b) Selective breeding
5.10 understand that plants with desired characteristics can be
developed by selective breeding
5.11 understand that animals with desired characteristics can be
developed by selective breeding.
c) Genetic modification
5.12 describe the use of restriction enzymes to cut DNA at
specific sites and ligase enzymes to join pieces of DNA together
5.13 describe how plasmids and viruses can act as vectors, which
take up pieces of DNA, then insert this recombinant DNA into
other cells
5.14 understand that large amounts of human insulin can be
manufactured from genetically modified bacteria that are grown
in a fermenter
5.15 evaluate the potential for using genetically modified plants
to improve food production (illustrated by plants with improved
resistance to pests)
5.16 understand that the term ‘transgenic’ means the transfer of
genetic material from one species to a different species.
Selective breeding
Selective breeding is a
method used for many
years by farmers and
growers to improve crops
and yields. For example,
milk production or
disease resistance.
Selective breeding
Selective breeding aims to improve the
features of a species.
Eg. To produce leaner pigs:
1.
Select pigs with the least fat and mate
them
2.
Select the best of the offspring and
mate these
3.
Continue selecting and breeding over
many generations.
Selective breeding
Disease-resistant wheat has
also been developed by cross
– breeding wheat plants with
disease resistance and wheat
plants with a high yield.
Selective breeding
Disease-resistant wheat has
also been developed by cross
– breeding wheat plants with
disease resistance and wheat
plants with a high yield.
The stalk of the wheat plant
has also been developed by
selective breeding to make it
shorter and stronger – helps
with harvesting.
Selective breeding
Milk yield in dairy
cattle has been
increased by
selecting bulls from
high yield herds and
breeding them with
cows that have the
best milk
production
Selective breeding
Milk yield in dairy
cattle has been
increased by
selecting bulls from
high yield herds and
breeding them with
cows that have the
best milk
production
ROSES –bred for
colour, shape and
scent.
SHEEP – bred for
quality wool and
lamb production
ROSES –bred for
colour, shape and
scent.
SHEEP – bred for
quality wool and
lamb production
APPLES – bred for
colour, taste and
texture
ROSES –bred for
colour, shape and
scent.
SHEEP – bred for
quality wool and
lamb production
DOGS – bred for
speed and
endurance
APPLES – bred for
colour, taste and
texture
ROSES –bred for
colour, shape and
scent.
SHEEP – bred for
quality wool and
lamb production
DOGS – bred for
speed and
endurance
CATS – bred for
best of breed shows
ROSES –bred for
colour, shape and
scent.
APPLES – bred for
colour, taste and
texture
SHEEP – bred for
quality wool and
lamb production
DOGS – bred for
speed and
endurance
CATS – bred for
best of breed shows
ROSES –bred for
colour, shape and
scent.
APPLES – bred for
colour, taste and
texture
LINSEED – bred
for oil production
Selective breeding
Advantages:
Produces an organism with
the right features for a
particular function.
Produces a more efficient
and economically viable
process for farming and
horticulture.
Selective breeding
Advantages:
Produces an organism with
the right features for a
particular function.
Produces a more efficient
and economically viable
process for farming and
horticulture.
Disadvantages:
Reduced number of alleles
in the population.
Reduced variation, so
unable to respond to
environmental change.
Can lead to other
unexpected health
problems.
Genetic Modification
Genetic Modification
Genetic Modification
Genetic
modification
(GM) is the use
of modern
biotechnology to
change the genes
of an organism
Genetic Modification
Why
GM?
Genetic Modification
Why
GM?
To improve crop
yields, eg. larger
tomatoes, more
oil from linseed
plants
Genetic Modification
Why
GM?
To improve
resistance to
pests or
herbicides, eg.
Pyrethrum
To improve crop
yields, eg. larger
tomatoes, more
oil from linseed
plants
Genetic Modification
Why
GM?
To improve
resistance to
pests or
herbicides, eg.
Pyrethrum
To improve crop
yields, eg. larger
tomatoes, more
oil from linseed
plants
To improve the
shelf-life of fast
ripening crops
such as tomatoes
Genetic Modification
Why
GM?
To improve
resistance to
pests or
herbicides, eg.
Pyrethrum
To improve crop
yields, eg. larger
tomatoes, more
oil from linseed
plants
To harness the
cell chemistry of
an organism, eg.
human insulin
To improve the
shelf-life of fast
ripening crops
such as tomatoes
Genetic Modification
Genes are often
transferred at an early
stage of development (in
both animals and plants) so
they develop with the
required characteristics
GM Stuffed Dog
(not really)
Genetic Modification
Genes are often
transferred at an early
stage of development (in
both animals and plants) so
they develop with the
required characteristics
GM Stuffed Dog
(not really)
Characteristics can then be
passed onto the offspring if
the organism reproduces
asexually, or is cloned.
Genetic Modification
“describe the use of
restriction enzymes to cut
DNA at specific sites and
ligase enzymes to join
pieces of DNA together”
Genetic Modification
How do we
change the
genes of an
organism?
Genetic Modification
How do we
change the
genes of an
organism?
That’s a really
good question
– let’s start
with an
example
Genetic Modification
A hormone
secreted by
the pancreas,
essential for
the control of
blood glucose.
The production
of human insulin
by genetic
engineering.
Genetic Modification
A hormone
secreted by
the pancreas,
essential for
the control of
blood glucose.
A Type 1
diabetes
patient needs
insulin
injections to
survive.
The production
of human insulin
by genetic
engineering.
Genetic Modification
A hormone
secreted by
the pancreas,
essential for
the control of
blood glucose.
A Type 1
diabetes
patient needs
insulin
injections to
survive.
The production
of human insulin
by genetic
engineering.
Insulin
medications
were
originally
taken from
cows, pigs or
salmon.
Genetic Modification
A hormone
secreted by
the pancreas,
essential for
the control of
blood glucose.
A Type 1
diabetes
patient needs
insulin
injections to
survive.
The production
of human insulin
by genetic
engineering.
Insulin
medications
were
originally
taken from
cows, pigs or
salmon.
Human insulin
first
synthesised
by genetic
engineering in
1978.
Genetic Engineering – The Process
Chromosome
Human
cell
Part of a human chromosome
Human insulin gene
Genetic Engineering – The Process
Chromosome
Human
cell
The gene for insulin
production is ‘cut out’ of
the human chromosome
using restriction enzymes
Part of a human chromosome
Human insulin gene
Genetic Engineering – The Process
Restriction enzymes, found
Thebe
gene for insulin
Human naturally in bacteria, can
production is ‘cut out’ of
cell
used to cut chromosome
the human chromosome
using restriction enzymes
(DNA) fragments at specific
points.
Chromosome
Part of a human chromosome
Human insulin gene
Genetic Engineering – The Process
Chromosome
Human
cell
Part of a human chromosome
The gene for insulin
production is ‘cut out’ of
the human chromosome
using restriction enzymes
Genetic Engineering – The Process
Bacterium
Bacterial DNA
Plasmid = small DNA
molecule, separate
from the chromosomal
DNA
Bacteria are
prokaryotic microorganisms. They do
not have a distinct
cell nucleus
Genetic
GeneticEngineering
Engineering––The
TheProcess
Process
Another restriction
enzyme is used to cut
open a ring of
bacterial DNA.
Genetic
GeneticEngineering
Engineering––The
TheProcess
Process
Another restriction
enzyme is used to cut
open a ring of
bacterial DNA.
Other enzymes (ligase
enzymes) are used to
insert the piece of
human DNA into the
plasmid.
Genetic
GeneticEngineering
Engineering––The
TheProcess
Process
Another restriction
is used
cut
Ligaseenzyme
enzymes
aretoenzymes
open
a ring ofreactions
that
catalyze
bacterial DNA.
which make bonds to join
together (ligate) smaller
molecules
to make
larger
Other enzymes
(ligase
ones.
enzymes) are
used to
insert the piece of
human DNA into the
plasmid.
Genetic Engineering – The Process
Plasmid now reinserted
into a bacterium which
starts to divide rapidly.
VAT
Genetic Engineering – The Process
As it divides it
replicates the plasmid,
and very soon there are
millions of them, each
with the code to make
insulin.
VAT
Genetic Engineering – The Process
Commercial quantities
of insulin are then
produced.
VAT
Genetic Engineering – The Process
The vector (the carrier) may be a virus rather
than a bacterial plasmid. The viral vector is
also known as a virion.
Genetic Engineering – The Process
The viral vector is
able to transport
the DNA directly
into the nucleus of
another cell.
The vector (the carrier) may be a virus rather
than a bacterial plasmid. The viral vector is
also known as a virion.
Genetic Engineering – The Process
The viral vector is
able to transport
the DNA directly
into the nucleus of
another cell.
After insertion of
the DNA the protein
is then produced
using the cells’ own
mechanism.
The vector (the carrier) may be a virus rather
than a bacterial plasmid. The viral vector is
also known as a virion.
Genetic Engineering – The Process
Human insulin was the first commercially
available protein produced by recombinant DNA
technology.
Genetic Engineering – The Process
Human insulin was the first commercially
available protein produced by recombinant DNA
technology.
Genetic Engineering – The Process
Large amounts of human insulin can be
manufactured from genetically modified bacteria
that are grown in a fermenter
Genetically Modified Crops
“Major doubts have been
raised over the safety of GM
foods by a new study ..”
“The Daily Mail’s
Frankenstein Food Watch
campaign has long
highlighted problems with
the lack of rigorous safety
assessments for GM crops
and food.”
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
Developed particularly for
insect / pest resistance
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
Bacterium (Bacillus
thuringiensis) has a toxin
that kills caterpillars and
insect larvae. Gene for this
toxin implanted in some
plant species using a
bacterial vector.
Developed particularly for
insect / pest resistance
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
have shown
Plants produce the toxin and
increased resistance to attack by insect
larvae. Unfortunately there are signs that
insects are developing immunity to the
Bacterium (Bacillus
toxin.
thuringiensis) has a toxin
that kills caterpillars and
insect larvae. Gene for this
toxin implanted in some
plant species using a
bacterial vector.
Developed particularly for
insect / pest resistance
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
In 2002 half the cotton
grown in China was
genetically modified to
produce a substance
poisonous to the cotton
bollworm, a pest of cotton
crops.
Developed particularly for
insect / pest resistance
Genetically Modified Crops
Most developments are in
the experimental or trial
stages. In the UK, GM
crops are grown only on a
trial basis.
Benefits of the GM cotton are a reduction
in pesticide use, and increase in yields and
profits, and health benefits to workers
(no more spraying of pesticides).
In 2002 half the cotton
grown in China was
genetically modified to
produce a substance
poisonous to the cotton
bollworm, a pest of cotton
crops.
Developed particularly for
insect / pest resistance
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
Disadvantages
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
• Can offer more nutritional
value and better flavour
Disadvantages
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
Disadvantages
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
Disadvantages
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
Disadvantages
Genetically Modified Crops
Advantages
• GM crops more productive and
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
• more GM crops can be grown
on relatively smaller parcels of
land.
Disadvantages
Genetically Modified Crops
Advantages
Disadvantages
• GM crops more productive and
• Exact insertion of the genes is
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
• more GM crops can be grown
on relatively smaller parcels of
land.
still a ‘hit or miss’ process.
Genetically Modified Crops
Advantages
Disadvantages
• GM crops more productive and
• Exact insertion of the genes is
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
• more GM crops can be grown
on relatively smaller parcels of
land.
still a ‘hit or miss’ process.
• GM food will end food
diversity if everyone grows
same standard crops.
Genetically Modified Crops
Advantages
Disadvantages
• GM crops more productive and
• Exact insertion of the genes is
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
• more GM crops can be grown
on relatively smaller parcels of
land.
still a ‘hit or miss’ process.
• GM food will end food
diversity if everyone grows
same standard crops.
• GM crops could cross-pollinate
with nearby non-GM plants and
create ecological problems.
Genetically Modified Crops
Advantages
Disadvantages
• GM crops more productive and
• Exact insertion of the genes is
have a larger yield
• Can offer more nutritional
value and better flavour
• Inbuilt resistance to pests,
weeds and disease
• Crops require less herbicides
and pesticides
• foods are more resistant and
stay ripe for longer, so
improving shelf life.
• more GM crops can be grown
on relatively smaller parcels of
land.
still a ‘hit or miss’ process.
• GM food will end food
diversity if everyone grows
same standard crops.
• GM crops could cross-pollinate
with nearby non-GM plants and
create ecological problems.
• Herbicide-resistant and
pesticide-resistant crops could
give rise to super-weeds and
super-pests that would need
newer, stronger chemicals to
destroy them.
Transgenic Species
“understand that the term
‘transgenic’ means the
transfer of genetic material
from one species to a
different species”
Transgenic Species
Glofish, the first transgenic
animals to be sold as pets.
http://en.wikipedia.org
Transgenic = an
organism whose
genetic material has
been altered using
genetic engineering
techniques.
Transgenic Species
Glofish, the first transgenic
animals to be sold as pets.
http://en.wikipedia.org
Glofish – fluorescence
gene from a jellyfish
inserted into zebrafish
embryo. Fish are now
brightly fluorescent in
both natural white light
and UV light.
Transgenic Species
An anti-blood-clotting
agent used in heart
surgery has been
produced in the milk of
transgenic goats. The
product is in the final
stages of clinical trials.
Transgenic Species
The gene for an enzyme,
alpha-anti-trypsin, which
blocks the action of the
protease enzymes in the
lungs of people suffering
from inherited
emphysema, has been
transferred to sheep.
Transgenic Species
The gene has been
inserted into milk
producing cells in sheep
mammary glands. The
sheep now produce the
enzyme in their milk,
from which it can be
separated and purified.
Transgenic Species
End of Section 5 Lesson 2
In this lesson we have covered:
• selective breeding
• genetic modification
• genetic engineering
• GM crops
• transgenic species