Genetic Engineering.pptx - RelyonBiology

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14 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

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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


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


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
-
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
-
3 Questions 1
-
3


Pg 361



PCR



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


The nucleus is extracted


The empty egg is fused with the donor cell


The cell is implanted into a female sheep


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
-
20


Pg 365
-
366


WRITE QUESTION AND ANSWER…..