Genetic Engineering
Genetic Engineering:
•
Genetic Engineering: process of altering
biological systems by the purposeful
manipulation of DNA
•
Applications:
–
Production of proteins (insulin, hormones,
vaccine)
–
Agriculture: plants can be more suitable for
growth and resistant to insects and bacteria
–
Medicine: diagnosis, medication, gene
replacement therapy
Methods:
•
Breeding
•
Investigation (Genetic testing for disease, test
paternity, investigating crime scenes)
•
Cloning (genes of interest, plants/animals)
Breeding
•
Breeding Methods: are used to get desirable
traits
–
Selective breeding: choosing an organism with
desirable traits
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Inbreeding: mating closely related organisms that
have desired traits
•
Decreases variation
–
Hybridization: mating organisms that are not
closely related for a mixture of both genes
Hybrids usually are sterile!
Test Cross Activity
•
Test cross is one way to determine genotype
–
HH or Hh? Cross it with a hh and observe
offspring
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If any express the recessive trait hh then the
parent was Hh
•
Pg:347
•
Read
•
Critical Thinking #1
-
5
Gene Cloning
•
Why?
•
Some people lack the essential proteins like
insulin, thyroxine, etc
•
Create organisms that have characteristics of
other organism
How to clone genes?
1.
Identify gene of interest
2.
Cut it out using a
restriction enzyme
•
Restriction enzyme
recognizes a specific DNA nucleotide
sequence and cuts at that site
3.
Cut a vector (usually a plasmid (circular DNA) of a
bacteria)
4.
Insert cut gene of interest into vector using sticky
ends (called splicing)
5.
Insert the plasmid back into the host (bacteria)
–
This technique is called
Recombinant DNA
to create a
transgenic organism
(organism that contains foreign
genes)
Diagram of Cleavage
GAATTC
CTTAAG
GAATTC
CTTAAG
G AATTC
CTTAA G
Diagram of Recombinant DNA
Activity in Text Book
•
Mini Lab 13
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1 on pg 351
•
Follow all steps in procedure
•
Answer analysis question #3
Gel Electrophoresis
•
Gel Electrophoresis: separates molecules
based on their rate of movement through a
gel under the influence of an electric field,
based on the size and charge of the molecules
How does Gel Electrophoresis work?
•
DNA fragments are made using restriction
enzymes
•
A mixture of fragments is placed in one end of
the gel
•
An electric voltage is applied to the gel
•
DNA (which is negative) would move to the
positive
•
Since there are tiny holes in the gel, the small
pieces move farther in the gel
•
This creates a unique DNA “fingerprint”
What can this be used for?
•
Since each person has a unique sequence of
DNA, the restriction enzyme creates different
size pieces for each persons DNA called a DNA
fingerprint
•
Related people have similar DNA and
therefore their DNA will be cut into similar size
pieces
•
It can be used to determine paternity and help
identify unknown DNA samples
Gel Electrophoresis
Activity in the textbook
•
Activity 13
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3 Questions 1
-
3
•
Pg 361
PCR
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Is the technique that allows us to make many
copies of genes.
•
First lets review some concepts….
•
How does DNA replicate in cells? Steps?
–
DNA unwinds and unzips
–
Free nucleotides attach to their complementary
bases
–
DNA polymerase attaches them together
Steps in PCR: Machine assisted DNA
replication
•
PCR stands for polymerase chain reaction
•
DNA of interest is placed in machine
•
DNA is heated
–
Heat will break the weak hydrogen bond btw the strands
•
Free nucleotides are added
•
DNA polymerase is added creating the new
complementary strands
•
Steps are repeated to create a large amount of DNA
•
Does your DNA polymerase work at high
temperatures? The DNA polymerase used is called taq
polymerase…. From bacteria that live in hot springs..
Cloning an organism…… OH DOLLY!
•
Steps:
–
Donor cell is taken from a sheep
–
An egg cell from a different sheep is taken
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The nucleus is extracted
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The empty egg is fused with the donor cell
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The cell is implanted into a female sheep
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Will eventually become a clone of the donor
Cloning an organism
Challenge question…
•
Would a clone have more mutations than a
normal offspring?
•
Would a clone have the same survival rate as a
normal offspring?
•
What are some dangers of this new
technology?
•
Should the government put restrictions on
human cloning?
HW
•
Questions 1
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20
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Pg 365
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366
•
WRITE QUESTION AND ANSWER…..
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