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14 Δεκ 2012 (πριν από 4 χρόνια και 9 μήνες)

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Warm up


Are genetically modified foods
bad? Be ready to defend your
position.

Unit 8 Part 2

1.
For thousands of years new varieties of cultivated plants and domestic
animals have resulted from
SELECTIVE BREEDING

for particular traits.

In Selective Breeding, only organisms with ____________________ ____________________ are bred


The purpose is to increase ________________upgrade _________________, __________________ disease



Selective breeding is also called
ARTIFICIAL SELECTION
,

because humans artificially select the plant or animals

that are going to breed and flourish,

according to what we want from them


Select the plants/animals with the best characteristics


Breed them with each other


Select the best of the offspring, breed again






CROSS BREEDING
_____________________________


(HYBRIDIZATION)


_______________________________________


________ ____________



Selective Breeding is used in many areas of modern farming to obtains:



Better beef


taste, texture




Better milk



breed milking cows to increase yield and resistance to disease



Better chickens


improve eggs size and number of eggs



Better wheat


better yields and disease
-
resistance



Bigger, better and more colorful flowers









INBREEDING


is used to :



____________________________________________________


Farmers use ____________________ _____________________


to produce more of the same type of a desired crop




The main draw back is a reduction in the gene pool



this can cause serious problems if a new disease appears, as all the plants or animals could be wiped out.



Selective Breeding in Pedigree Dogs causes bad health















Desired Traits

Yield


Quality, Decrease

Can be accelerated by using
artificial insemination of livestock



increased genetic disorders

Newest technique:
Plant tissue cultures

Select two
di
ffere
n
t parents

Obtain a new (better)
mi
x

HYBRID VIGOR

MAINTAIN desired characteristics

Vegetative propagation

Less variety!



Loss of immune function

An attempt to improve the organism

Despite their remarkable dissimilarity to each other,
broccoli, kohlrabi, black mustard, brussel sprouts,
and swedish turnips were all bred from the same
wild ancestral species,
Brassica Oleracea


each over
the course of mere
thousands of years


Human beings have similarly produced all sorts of genetic
monstrosities (?)
through artificial selection



cows with udders bulging with gallons of surplus milk,

dogs that can fit inside designer purses,

bananas with easily transplantable parts,

seedless watermelons, 300
-
kg pumpkins, purple carrots,


and much, much more.

Carrot Purple Haze (100 seeds approx) 70 days.
Here is the first
-
ever hybrid purple Carrot
-

a
return to when wild carrots were naturally
purple. Very vigorous and easy to grow, this
delicious vegetable will be the centerpiece of
your garden and the talk of the neighborhood!
Purple Haze is a Nantes
-
type carrot, with strong
growth and a delectable...

If a single day represented the time the earth has been around ( 4.5
billion years) each second would be more than 52,000 years

The loss of genetic seed diversity facing us today may lead
to a catastrophe far beyond our imagining. The Irish potato
famine, which led to the death or displacement of two and
a half million people in the 1840s, is an example of what
can happen when farmers rely on only a few plant species
as crop cornerstones.

One blight wiped out the single potato type that came from
deep in the Andes mountains; it did not have the necessary
resistance. If the Irish had planted different varieties of
potatoes, one type would have most likely resisted the
blight

Types of stem cells
:


1.
Embryonic stem cells
(Pluripotent) isolated from blastocysts.



Embryonic stem cells can differentiate into more than 200 cell types of the adult
body when given necessary stimulation.


2.
Adult /
tissue
-
specific stem cells
(Multipotent)


Can only form a limited number of cells types .



Act as a repair system for the body by replenishing specialized cells.



Maintain the normal turnover of regenerative organs such as blood, skin or intestinal tissue



The UMBILICAL CORD

of a newborn baby is also a source of blood stem cells


3. Replacing diseased cells with healthy cells, a process called cell
therapy, is a promising use of stem cells in the treatment of disease.

Blood Cells

to treat

LEUKEMIA

Nerve Cells

to treat


Parkinson’s Disease


Spinal Cord Injuries

Muscle cells to treat


Muscular Dystrophy

2.
STEM CELLS
are undifferentiated or blank cells that have not yet fully specialized.



They are like a blank microchip that can be programmed to perform particular tasks


They have the ability to undergo mitotic cell division and differentiate into
a wide range of specialized cell types
.

Selective

Breeding

Artificial Selection
:

Cross Breeding:

Inbreeding:

Plant processes
:


Vegetative Propagation


Plant tissue cultures


Advantages / Disadvantages

STEM CELLS

TYPES:

Use:

Warm up (4/23)


Why are people interested in
stem cells?

10. CLONING CREATES A COPY OF LIVING MATTER

The clones, or copies have ____________________________________


Practical applications in:

1.
Obtain an ___________________________, remove the ________________________


2.
Remove the __________________ from a cell of the ____________________________


3.
Put the _____________________ in to the ___________________________________


4.
All the _________________________________________________________________


5.
An ________________________


6.
Implant in to a _______________________________ who carries to term and delivers


STEPS TO PRODUCE A CLONE:

Identical DNA

egg

Nucleus

Nucleus

Donor

(thing getting cloned)

Donor nucleus

Denucleated

Egg cell

DNA is from the donor

Electric shock fuses cells

foster mother

Agricultural uses, future
biotransplantation

11.
DIAGNOSTIC TECHNIQUES:


Dna PROFILING USING GEL ELCTROPHOREISIS

Used for:

PROCESS:


Use of ___________________________ to separate segments of DNA based on _____________



1.
DNA is cut in to fragments using ________________________ ___________________________


2.
The segments are placed in to wells that have been cut in to a large gel

3. Turn on the electricity

4. The segments migrate through the gel from the


side to the + side.


The smallest molecules move the farthest

5. Produces a fingerprint

Electric Field

size

Restriction

Enzymes

Video

Crown Jewels


In your groups
try to identify the
criminal using gel electrophoresis


(cut in the appropriate spots for
each DNA, and run the gel
electrophoresis)


Warm up 4/26


What biotechnology tool could
we use in a Criminal
Investigation?

Also, did you hand in your warm
-
ups from last week???

Warm up 4/27


What is one positive and one
negative thing about Genetically
Modifying foods?

4. Genetic engineering

is the alteration of genetic code by artificial means,

and is therefore different from traditional selective breeding.


Examples include:


___________________ ______________

Allows for:


Producing proteins


Transferring new genes in to organisms



Insertion of human genes into sheep so that they secrete alpha
-
1
antitrypsin in their milk


a substance used to treat lung disease


Genetic engineering has created a goat with spider genes that
creates "silk" in its milk



Insertion of human genes into bacteria to produce insulin

Genetic engineering works because there is one
language of life:


human genes work in bacteria, monkey genes work in
mice and earthworms.

Tree genes work in bananas and
frog genes work in rice.

There is no limit in theory
to the potential of genetic engineering.



Molecular biologists have discovered many enzymes which change the
structure of DNA in living organisms. Some of these enzymes can cut and join
strands of DNA. Using such enzymes, scientists learned to cut specific genes
from DNA and to build customized DNA using these genes.


Tomatoes are sensitive to frost. This shortens their growing season. Fish, on the
other hand, survive in very cold water. Scientists identified a particular gene which
enables a flounder to resist cold and used the technology of genetic engineering to
insert this 'anti
-
freeze' gene into a tomato. This makes it possible to extend the
growing season of the tomato.



Taking the gene that programs poison in the tail of a scorpion, and combining it with a
cabbage.


These genetically modified cabbages kill caterpillars because they have learned to grow
scorpion poison (insecticide) in their sap

Golden rice

Monsanto’s

triple
-
stack corn

Transgenic organisms
contain genetic material
from another organism

5. Recombinant DNA

can turn bacterial cells in to a protein factory!


Restriction enzymes are used to cut DNA.


The gene of interest can be “cut out” of a human cell.


Bacterial cells contain special rings of DNA called plasmids.


The same restriction enzyme is used to cut open the plasmid.


The gene of interest is inserted in to the plasmid




THIS
RECOMBINANT DNA
CONTAINS GENETIC MATERIAL FROM


2 DIFFERENT SOURCES



The plasmid is inserted in to another bacterial cell.


The bacterial cell is allowed to reproduce


The new bacterial cells will produce the proteins




THESE BACTERIAL PLASMIDS ARE KNOWN AS
VECTORS



THEY CAN CARRY DNA FROM ONE SPECIES TO ANOTHER


These


___________________ ________________________


become protein factories!


Used to produce:


1.
______________________ for diabetics


2.
_______________ __________________


3.
Factors for hemophilia

T
r
a
n
sge
n
ic

Bacteria

Insulin

Growth Hormone

TRANSFORMATION:

DNA from an outside
source

becomes

part of a cell

Bacillus thuringiensis
, commonly known as Bt, is a bacterium found in soil.

Some strains produce proteins that kill insects.

Today, genetically engineered plants produce their own Bt “killer” protein.

This has been effective against the European corn borer, a major pest of North American corn.

This has eliminated the need to spray pesticides.

6. TRANSGENIC PLANTS

Transgenic plants

possess ________________________________that has been
transferred from a different ______________. Although DNA of another species
can be integrated in a plant genome by natural processes, the term "transgenic
plants" refers to plants created in a laboratory using
recombinant DNA

technology. The aim is to design plants with specific characteristics by artificial
insertion of genes from other species or sometimes entirely different kingdoms

7. PRODUCTION OF A TRANSGENIC PLANT

Genetic material

species

-

Constant exposure to a toxin
creates
evolutionary pressure

for
pests resistant to that toxin.
Already, a
Diamondback moth

population is known to have
acquired resistance to Bt in spray
form (i.e., not engineered) when
used in organic agriculture.
[

Spores and crystalline insecticidal
proteins

produced by
B.
thuringiensis


have been used to control insect pests
since the 1920s

The
Belgian

company
Plant
Genetic Systems

was the first
company (in 1985) to develop
genetically engineered
(
tobacco
) plants with insect
tolerance by expressing
cry

genes from
B.
thuringiensis

+ Insecticide use on
cotton and corn is less,

better for the
environment

+ The toxin expression is
contained within the
plant system so only
those insects that feed on
the crop perish

There is clear evidence from laboratory
settings that Bt toxins can affect non
-
target
organisms. Usually,
butnot

always, affected
organisms are closely related to intended
targets
[.

Lovei

and
Arpaia

2005 and
Hilbeck

and Schmidt 2006].


Typically, exposure occurs through the
consumption of plant parts such as pollen or
plant debris, or through Bt ingested by their
predatory food choices.

Nevertheless, due to significant data gaps,
the real
-
world consequences of Bt
transgenics

remains unclear

-
A 2007 Study by
Greenpeace

Suggested the
possibility of a slight
but statistically
meaniningful

risk of
liver damage in rats

What Are Genetically Engineered Foods?

Genetically engineered foods are produced from crops whose genetic makeup has been altered,
to give the plant a desirable trait.

Genetically engineered foods are also known as biotech, bioengineered, and genetically modified.

The first genetically engineered whole product
--
a tomato
--
went on the market in 1994.


The FDA determined that the new tomato, which could be shipped vine
-
ripened
without rotting rapidly, was as safe as other commercial tomatoes


Other GE food products include: canola oil, corn, potatoes, soybeans, squash, sugar beets, corn

F
our objectives in crop plant genetic engineering research.



1.
To improve biological protection of crops against insects, weeds and fungi by inserting genes for the natural
production of an insecticide (Feder, 1996) or for resistance to fungi or an herbicide (Hinchee et al, 1988).


2
. To elevate levels of important nutrients so as to make crops more nutritious.


3. To obtain better control of ripening and post
-
harvest storage life to assure that produce are in peak


condition when taken to market (Maryanski, 1995).



4. To specifically modify genomes to produce a specific product (edible vaccines in potatoes
-

Pollack, 2000).


1.
That new products will cause allergic reactions in people


To boost the methionine levels in soybeans, a gene from Brazil nuts was introduced into a soybean.


(Sometimes the introduction of a new gene leads to the production of a new protein.)


In this case the new protein caused a “life
-
threatening allergic reaction in people”

___
2. That the Bt insecticide produced in plant tissue


will poison people eating the plant.

___
3. That crops, especially fruits, produced using genetic engineering


will taste bad.

__ _
4. That GMOs will have an adverse effect on wild plants and animals.

__ _
5. That genetically engineered crops will have an


adverse effect on natural ecosystems.

___
6. That the viral and bacterial vector and activator genes used


may be recombined in the wild and form some deadly new pathogens.


http://yale.edu/ynhti/curriculum/units/2000/7/00.07.02.x.html

9. There may be problems associated with
Genetically modified foods

8.
GENETICALLY ENGINEERED FOODS

ARE ON THE SHELVES TODAY
!

TRANSGENIC ORGANISM:

BIOTECHNOLOGY


GENETIC
ENGINEERING

Recombinant DNA:

Step wise procedure:

Used to produce:

Transgenic Plants:

GM foods:

Warm
-
up

4/28


A tomato plant that produces a
fish protein so it can grow in the
cold is an example of a(n):


A) A
franken
-
food


B) Transgenic organism


C) Cloning


D) DNA profiling