Biotechnology

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14 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

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BIOTECHNOLOGY

Unit 6

Maury


http://www.youtube.com/watch?v=ZD78
-
CCPhAQ


What did they do to tell who the father was?


How do they do these tests?


How do they know for SURE?


What is biotechnology?


Bio = Life


Technology = machinery, equipment, or the
application of knowledge




Technology that relates to the field of
biology or living things


Manipulating
living

organisms using various
types of
technology

to produce more useful
qualities


using better genes and traits


Allows the best or desired traits to be
expressed.


Research in Biotechnology

1.
Help humans create
crops

that can be frost
resistant

2.
Use transgenic organisms to help
medical
researchers

model human physiology for
testing

3.
Help
industries

to create bacteria to break
down
pollutants

into harmless products

4.
Pharmaceutical companies use recombinant
DNA to cheaply produce
human hormones
(insulin)

and other proteins

5.
Help solve
crimes

and
determine familial
relationships


Gel Electrophoresis


A method used in biochemistry and
molecular biology to separate DNA or RNA
molecules by size to compare DNA data.


Also called a “DNA fingerprint”


Unique to each person

What can this be used for?


Paternity Tests


Who is the father?



Familial Relationships


Who is the mother?


Who are the siblings, cousins, grandparents, etc.?



Evolutionary Relationships


How closely related are two organisms (humans & apes)?



Crime Scene Investigations


Who committed the crime?

Basic Steps..

1.
Extract DNA sample


2.
Cut DNA into smaller pieces using Restriction
Enzymes


3.
Put the smaller DNA fragments into the Gel Tray


4.
Use
an electric charge
to separate the pieces of
DNA


5.
Analyze the DNA fragments

Goal of Gel Electrophoresis

1.
The process of Gel Electrophoresis works to
separate

and

analyze

DNA fragments
according to their
size

&

shape
.


2. In order to cut the DNA into fragments,
restriction enzymes

are used.


These are specific enzymes (proteins) that
recognize specific sequences of DNA and then cut
it in half.


3. Samples of DNA fragments are loaded onto a
GEL ELECTROPHORESIS.


4. DNA fragments move in the Gel due to opposite
charges (DNA is negatively charged)


The
SMALL strands move further
down the Gel than
the LARGER strands of DNA.


Since they are larger and heavier, the
LARGER
strands do not move as far down the Gel

5. The groups of DNA fragments show up as
small lines in the Gel


6. Now a DNA FINGERPRINT is created, which
can be analyzed.

Let’s Take a look…


http://www.youtube.com/watch?v=PSwlCk_Z
02c&feature=related


Check Point

1.
What are
the steps used in Gel
electrophoresis?


2.
Where
would you find the shortest stand of
DNA
?


3.
What
causes the fragments on DNA to move?


DNA fingerprinting
applications

Sample Problems

Genetic Engineering


Transgenic Organisms


What is a transgenic organism?


Let’s break down the word…


Trans = across


Genic

= genes


Organism = Living thing


Transgenic Organisms are:


It is an organism that has had genes inserted (or
moved into) from a different organism


Transgenic organisms are made from combining
different DNA


Genetically Modified Food
(GMO)


Genetically Modified Food
(GMO)


What is Genetically Modified
Food (GMO)?


It is a crop or food that has been intentionally
modified, altered or changed.


What is Selective Breeding…


A type of genetic engineering


Choosing organisms (plants, animals) with
the best traits (genes) and breeding them
together to produce better (bigger, stronger)
offspring

Can you thinks of a real life
example of selective breeding?

How did THIS happen?!

Glow
-
in
-
the
-
dark PIGS?!


A desired gene from one organism (the glow
gene from a fire fly) was inserted into the
DNA of a pig



Through MITOSIS the pig’s cells began
replicating the glow
-
in
-
the
-
dark gene (the
desired gene)



Let’s take a closer look at this…


What is Recombinant DNA


When DNA from
two different
organisms
come together, the DNA becomes
RECOMBINANT DNA


What does recombinant (recombine) mean?




The organism that receives the
recombinant DNA will use it as if it were
its own DNA.



Also know as…


Transgenic Organisms

How do scientists create
DNA?


Its all about using BACTERIA!


This is because bacteria have DNA rings
called PLASMIDS.

Steps for Creating a Transgenic
Organism

1.
R
emove the plasmid

2.
C
ut the bacterial DNA using restriction enzymes,
leaving an open “sticky end.”

3.
Remove and cut a desired gene from a different
organisms (foreign DNA), also leaving an open “sticky
end.”

4.
Then glue a piece of foreign (human, plant, animal)
DNA back into the plasmid using the enzyme
Ligase

and sticking the “sticky ends” together.

5.
Insert the plasmid back into the Bacteria

6.
Now, the bacteria will reproduce the new gene (in the
plasmid DNA) to make larger quantities of the desired
gene or trait.

All bacteria are…


IDENTICAL


REMEMBER: bacteria divide using asexual
reproduction!



SO…


Every new bacteria will be making exact copies of
the desired gene!

Applications of

Recombinant
DNA


Bacteria


used
to produce
hormones,
antibiotics and Insulin


Plants


made to be resistant to
herbicides
and Pesticides


Animals


Cloning



Replacement
of genes which cause
disorders (aka Gene Therapy)


Such as Cystic Fibrosis


Severe Combined
Immunodeficiency




Check Point 1

1.
What is a Transgenic Organism?

2.
How are transgenic organisms made?

3.
What is a GMO?

4.
What is a real
-
life example of a GMO?

5.
What is selective breeding?

6.
What is a real
-
life example of selective
breeding?

Human Genome Project


A collaborative effort by scientists around the
world to map the human genome


Genome

= all of an organism’s hereditary
information


Completed in 2003


Can be used to determine if people carry
genes for certain traits or diseases


Can be used to determine the locations of
genes on chromosomes

Problems with the Human
Genome Project:


What do we do with the information?


Designer babies?


Abortion of defective babies?


Sterilize carriers?


Will insurance companies be able to deny you
coverage because of your genes?


Can pharmaceutical companies “copyright” a
gene sequence?


If so, what happens to people with that gene?


http://www.youtube.com/watch?v=XuUpnAz5y1g&feature=related


Cloning


A
clone

is an organism that is a perfect copy
of another organism


Clones can happen in nature


Identical twins


Some organisms (like bacteria) “clone”
themselves through asexual reproduction

Cloning


Cloning mammals is really hard


we used to
think it was impossible


Dolly the sheep


1996

Making a Clone:


1. A cell is taken from the donor.


2. An egg is taken from another adult animal.


3. The egg has all of its genetic material (DNA)
removed.


4. The genetic material (DNA) is taken from the
donor cell and placed into the now
-
empty egg.


5. The egg with the donor’s genetic material is
placed in a foster mother where it will divide
and grow into a baby. This is the
clone
, a
perfect copy of the original donor.

Problems with Cloning:


Most attempts to clone have failed


Of the attempts that succeed, most have
health problems


Large offspring syndrome (LOS)


clone
babies tend to be larger than other babies of
their species


the enlarged organs cause
health problems


Gene expression


a clone may not express
the same genes as the original, even if they
are genetically identical

Problems with Cloning


Clones tend to have weak immune systems


they are more vulnerable to disease


Cells tend to have more trouble dividing
properly the older an organism is


if you
take an “old” cell from an older organism and
grow a younger organism (clone) from it,
there will be even more dividing problems


Therefore, it is currently illegal to clone
humans in the United States

What is Gene Therapy?


The transplantation of normal genes into
cells in place of missing or defective ones in
order to correct genetic disorders.

Gene Therapy


Still in the theory/testing stages


1. A person is tested for faulty genes


2. A person with a healthy copy of the gene donates
some cells and has the healthy copy cut out using
restriction enzymes


3. The healthy copy is loaded into a
vector

(carrier),
usually a virus.


4. The sick person is infected with the virus, which
will inject the gene into their cells, hopefully
“patching up” the problem.


http://www.youtube.com/watch?v=CkWep1Z0gCw

Diseases that can be cured
with Gene Therapy


1.
Cystic fibrosis

= causes respiratory tract to
produce a thick mucus (instead of the normal
thin, watery kind) that can clog passageways
and lead to suffocation. People with CF
usually die by 30


2.
Severe Combined Immunodeficiency

(SCID) = affects two kinds of infection
fighting cells, leaving patients susceptible to
diseases. Women are usually only carriers,
men are usually the ones affected.

Problems with Gene Therapy


Very expensive to research and test


We don’t know what the side effects will be


We still don’t understand everything about
genes


how do we know this will fix the
problem?

Stem Cell Research


Stem cells

are a “blank slate”


they can
become any kind of cell through
differentiation



ex. Heart cell, lung cell


Two main kinds:


Adult stem cells

= come from adults


Embryonic stem cells
= come from embryos
grown in the lab

Stem Cell Research


Scientists prefer to work with embryonic
stem cells


Easier to identify, isolate, and harvest


More of them than adult stem cells


Grow more quickly and easily


Easier to manipulate

Problems with Stem
Cell
Research


Financial


It is very expensive


Ethical


Destroying embryos


Stem cells can cause cancer if they divide out of
control


Why use embryonic when adult cells are available?


Adult stem cells avoid problem of immune
rejection