AP Biology Unit 3 biotechnology notes - NGHS-Science

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23 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Biotechnology



Recombi nant DNA Technol ogy




Gene Sequenci ng (Human Genome Project)




Cl oni ng




Stem Cel l Research




Gene Therapy




DNA Fi ngerpri nti ng (and other Forensi cs appl icati ons)


16.1 DNA Cloning



1.
Cloning
i s the producti on of i denti cal copi es of D
NA through some asexual means.

a.

An underground stem or root sends up new shoots that are cl ones of the parent pl ant.

b.

Members of a bacteri al col ony on a petri di sh are cl ones because they al l came from di vi sion of the same cel l.

c.

Human i denti cal twi ns are c
l ones; the ori gi nal single embryo sep
arate to become two i ndi vi duals. (Arti fi ci al
Twi nni ng)

d.

Somatic Cell Nuclear Transfer (SCNT)


adul t cel l s used to create an embryo


2.

Gene cloning

i s producti on of many i denti cal copi es of the same gene.

a.

If the i nsert
ed gene i s repl i cated and expressed, we can recover the cl oned gene or protei n product.

b.

Cl oned genes have many research purposes: determi ni ng the base sequence between normal and mutated
genes, al teri ng the phenotype, obtai ni ng the protei n coded by a speci
fi c gene, etc.

c.

Humans can be treated wi th
gene therapy
: al terati on of the phenotype i n a benefi ci al way.




3.
R
ecombinant DNA Technology


1.

Recombinant DNA

(rDNA)
contai ns DNA from two or
more di fferent sources.


2.

To make rDNA, techni ci an sel ects a
vector.


3.

A

vector

i s a pl asmi d or a vi rus used to transfer
forei gn geneti c materi al i nto a cel l.


4.

A
plasmid

i s a smal l accessory ri ng of DNA i n the
cytopl asm of some bacteri a.


5.

Pl asmi ds were di scovered i n research on
reproducti on of i ntesti nal ba
cteri a

Escherichia coli.


6.

Introducti on of forei gn DNA i nto vector DNA to
produce rDNA requi res two enzymes.


a.

Restriction enzyme

i s a bacteri al enzyme that
cuts DNA, i t creates fragments of DNA wi th
“sti cky ends”



b.
DNA ligase
joi ns fragments t
ogether













C. The Polymerase Chain Reaction

1. PCR can create millions of copies of a single gene or a specific piece of DNA in a test tube.

2. PCR is very specific

the targeted DNA sequence can be less than one part in a million of the total DNA
sample;
therefore a

single gene can be amplified using PCR.

3. The polymerase chain reaction (PCR) uses the enzyme DNA polymerase to carry out multiple replications (a chain
reaction) of

target DNA.

4. PCR automation is possible because heat
-
resistant DNA
polymerase from
Thermus aquaticus,
which grows in hot
springs, is an

enzyme that withstands the temperature necessary to separate double

stranded DNA.


D. Analyzing DNA Segments

1. Mitochondria DNA sequences in modern living populations can decipher the ev
olutionary history of human
populations.


2.
DNA fingerprinting
is the technique of using DNA fragment lengths, resulting from restriction enzyme cleavage and
amplified by PCR, to identify particular individuals.


a. DNA is treated with restriction enzymes

to cut it into different sized fragments.

b. During gel electrophoresis, fragments separate according to length, resulting in a pattern of bands.

c. DNA fingerprinting can identify deceased individuals from skeletal remains, perpetrators of crimes from bl
ood or
semen samples, and genetic makeup of long
-
dead individuals or extinct organisms.


3. PCR amplification and DNA analysis is used to:


a. detect viral infections, genetic disorders, and cancer;

b. determine the nucleotide sequence of human genes: the
Human Genome Project; and

c. associate samples with DNA of parents because it is inherited.






16.2 Biotechnology Products

1.

Geneti cal l y engi neered organi sms can produce bi otechnol ogy products.

2.

Organi sms that have had a forei gn gene i nserted i nto t
hem are
transgenic
.

A.

Transgeni c Bacteri a

1.

Bacteri a are grown i
n l arge vats cal l ed bi oreactors, they can make products such as i nsul in and human growth
hormone, and vacci nes

2.

Transgeni c bacteri a have been produced to
i mprove the heal th of pl ants and

d
egrade substances, such as oi l

3
.

Transgeni c bacteri
a can produce chemi cal products, such as phenyl al anine (arti fi ci al sweeteners)

5.

Transgeni c bacter
i a process mi neral s, bacteri a can extra urani um from l ow grade ore


B.

Transgeni c Pl ants

1.

Forei gn genes

now gi ve cotton, corn, and potato strai ns the abi l ity to produce an i nsect toxi n and soybeans are now
resi stant to a common herbi ci de.

5.

Pl ants are bei ng engi neered to produce human protei ns i ncl udi ng hormones, cl otti ng factors, and anti bodi es i n
thei r s
eeds; anti bodi es made by corn, del i ver radi oi sotopes to tumor cel l s and a soybean engi neered anti body can
treat geni tal herpes.


C.

Transgeni c Ani mal s

1.

Ani mal use requi res methods to i nsert genes i nto eggs of ani mal s

(earl y i n devel opment)
.

Usi ng thi s t
echni que,
many types of ani mal eggs have been i njected wi th bovi ne growth hormone (bGH) to produce l arger fi shes, cows,
pi gs, rabbi ts, and sheep.



Gene pharmi ng


i s the use of transgeni c farm ani mal s to produce pharmaceuti cal s; the product i s obtai nable f
rom the mi l k of
femal es.


D.

Cl oni ng Transgeni c Ani mal s

1.

For many years, i t was bel i eved that adul t vertebrate ani mal s could not be cl oned; the cl oni ng of Dol l y i n 1997
demonstrated thi s can be done.

2.

Cl oni ng of an adul t vertebrate woul d requi re that a
l l genes of an adul t cel l be turned on agai n.

3.

Cl oni ng of mammal s i nvol ves i njecti ng a 2n nucl eus adul t cel l i nto an enucl eated egg.

4.

The cl oned eggs begi n devel opment i n vi tro and are then returned to host mothers unti l the cl ones are born.








Scenario 1: A well
-
loved horse named Barbero breaks his leg in
a race. Many people were praying for his well being and
thousands of dollars were spent trying to get him to recover.
Mail and flowers poured into

the animal hospital and stable
where Barbero lived. Alas, after a year of poor recovery, the
decision was made to euthanize Barbero. The owners save
sample of his DNA so that Barbero can be cloned. Do you think
they should clone him? Why or why not
.

Scenario 2: Melissa is a happy 5 year old who is loved by
her family. She becomes ill and is diagnosed with
childhood
leukemia. A desperate search ensues to find

a bone marrow
donor who
s
e

type matches Melissa. After a year of
searching, Melissa’s outlook is grim. Her family decides to
clone Melissa so that her clone could be the bone marrow
donor. Do you th
ink this is a god idea? Why or why not.


16.3 Genomics


Geneti cs i n the 21
st

century concerns
genomics
: the study of genomes of humans and other organi sms.


A. Sequenci ng the Bases

1.

The Human Genome Project has produced a worki ng draft of al l the base pai rs i n al l our chromosomes.

2.

The task t
ook 13 years to l earn the sequence of the three bi l l i on base pai rs al ong the l ength of our chromosomes.

B.

Genome Compari sons

1.

There i s l i ttl e di fference between the sequence of our bases and other organi sms whose DNA sequences are
known.

2.

We share a l arge num
ber of genes wi th si mpl er organi sms (e.g., bacteri a, yeast, mi ce); perhaps our uni queness i s
due to regul ati on of these genes.

3.

Researchers found that certai n genes on chromosome 22 di ffered i n humans and chi mpanzees: those for speech
devel opment, heari ng,
and smel l.

4.

Many genes found were responsi bl e for human di seases.

C. The
HapMap Project

--

Thi s project wi l l catal og sequence di fferences, cal l ed hapl otypes, i n humans.

D.

The Geneti c Profi l e

1.

DNA chi ps (or DNA mi croarrays) wi l l soon be avai l able that wi l
l rapi dly i denti fy a person’s compl ete genotype; thi s is
cal l ed the
genetic profile
.

2.

DNA profi l es can determi ne i f a person has an i ncreased ri sk for a parti cul ar di sease; appropri ate i nterventi on can
then be admi ni stered.

3.

The geneti c profi l e can be used t
o determi ne i f a parti cul ar drug therapy i s appropri ate i n a speci fi c cl inical
condi ti on.

E.

Proteomi cs

1.

Proteomics
i s the study of the structure, functi on, and i nteracti on of cel l ul ar protei ns.

2.

The i nformati on obtai ned from proteomi c studi es can be used i n de
si gni ng better drugs, and to correl ate drug
treatment to the parti cul ar genome of the i ndi vi dual.

F.

Bi oi nformati cs

1.

Bioinformatics
i s the appl i cation of computer technol ogi cs to the study of the genome.

2.

Informati on obtai ned from computer anal ysis of the genom
e can show rel ati onships between geneti c profi l es and
geneti c di sorders.


16.4 Gene Therapy

1.

Gene therapy

i nvol ves procedures to gi ve pati ents heal thy genes to make up for a faul ty gene.

2.

Gene therapy al so i ncludes the use of genes to treat geneti c d
i sorders and vari ous human i l l nesses.

3.

There are
ex vivo

(outsi de body) and
in vivo

(i nsi de body) methods of gene therapy.