Transcript Bacteria Transformation

What Is the Problem?
Irene is 10 years old and in the last few weeks, she suddenly experienced extreme tiredness,
weight loss, and increased thirst. Her parents were concerned, so they took her to the doctor.
Dr. Ross took Irene’s blood to test for her blood sugar. The results of the test indicated that
she was a diabetic. When the doctor shared the results, Irene broke into tears. The
combination of her sudden poor health and the news of her diabetes was too much for her to
handle. “I don’t understand. What is diabetes and how can I get better?” The doctor felt bad
for Irene. She said, “Irene, I can explain how this happened, and how we can fix it.”
Irene is diabetic
What Is Diabetes?
People with diabetes may not have enough
insulin or may not be able to use it properly.
Insulin is a hormone that controls the level of
blood sugar (also called glucose) in your body.
The sugar then builds up in the blood and
overflows into the urine, passing out of your
body unused. This deprives you of an important
source of energy.
How Can Irene Get Better?
All people with type 1 diabetes, and some people
with type 2, need to take insulin to help control
their blood sugar levels.
Type 1 diabetes means your body doesn’t make
any insulin.
Type 2 diabetes means your body either doesn’t
make enough insulin or doesn’t use it properly.
The goal of taking insulin is to keep your blood
sugar level in a normal range as much as possible
so you’ll stay healthy.
Over time, high blood sugar levels can cause
serious health problems such as blindness and
kidney failure.
How Can We Make Insulin?
The first successful insulin preparations came from cows
(and later pigs). In the 1980's technology had advanced to
the point where we could make human insulin. The
technology which made this approach possible was the
development of recombinant DNA techniques. In simple
terms, the human gene which codes for the insulin protein
was cloned (copied) and then put inside of bacteria.
A number of tricks were performed on this gene to make the
bacteria want to use it to constantly make insulin. Big vats of
bacteria now make tons of human insulin. From this,
pharmaceutical companies can isolate pure human insulin
Describe how to make insulin for Irene.
Aim: How to Make Human Insulin?
Step #1: Extract the DNA from a human cell.
Aim: How to Make Human Insulin?
Step #2: Remove the plasmid from a bacterium.
What is a plasmid?
• Small, circular
DNA molecule presents in bacteria.
Aim: How to Make Human Insulin?
Step #3:Use restriction enzymes to isolate a segment of
(DNA) that contains the insulin gene
Aim: How to Make Human Insulin?
Step #4: Treat the bacterial plasmid with the same
restriction enzyme.
Aim: How to Make Human Insulin?
Step #5: Binds the insulin gene with the opened
plasmid to form a recombinant plasmid.
Aim: How to Make Human Insulin?
Step #5: Binds the insulin gene with the opened
plasmid to form a recombinant plasmid.
Aim: How to Make Human Insulin?
Step #6: The recombinant plasmid is re-inserted
back into the bacterium.
Aim: How to Make Human Insulin?
Step #7: Bacteria clone into a large number of
identical daughter cells .
Aim: How to Make Human Insulin?
Step #8:The recombinant plasmid replicates as
part of the bacteria’s DNA.
Aim: How to Make Human Insulin?
Step #9. Insulin is produced by bacteria and
extracted for human use.
Gene for human insulin
Recombinant DNA
DNA
Figure 13-9 Making Recombinant
Gene for human insulin
Sticky ends
Bacterial cell containing gene for human insulin
Plasmid
DNA recombination
DNA insertion
Recombinant
DNA
Gene for human
insulin
Gene for human
insulin
Human Cell
Sticky
ends
DNA
recombination
DNA
insertion
Bacterial Cell
Bacterial
chromosome
Plasmid
Bacterial cell containing
gene for human insulin
•
_____
Bacteria clone into a large number of identical daughter cells
•
_____
Binds the insulin gene with the opened plasmid to form a recombinant plasmid.
•
_____
Extract the DNA from a human cell.
•
_____
Insulin is produced by bacteria and extracted for human use.
•
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Remove the plasmid from a bacterium.
•
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The recombinant plasmid is re-inserted back into the bacterium.
•
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The recombinant plasmid replicates as part of the bacteria’s DNA.
•
_____
Treat the bacterial plasmid with the same restriction enzyme.
•
Use restriction enzymes to isolate a segment of (DNA) that contains the insulin
gene.
_____
1. Extract the DNA from a human cell.
2. Remove the plasmid from a bacterium.
3. Use restriction enzymes to isolate a segment of (DNA) that contains the insulin gene.
4. Treat the bacterial plasmid with the same restriction enzyme.
5. Binds the insulin gene with the opened plasmid to form a recombinant plasmid. The recombinant plasmid is re-inserted back into the
bacterium.
6. Bacteria clone into a large number of identical daughter cells
7. The recombinant plasmid replicates as part of the bacteria’s DNA.
8. Insulin is produced by bacteria and extracted for human use.
Genetic engineering is a technique used by scientists to combine or splice
genetic material from different organisms. Gene splicing involve changing the
normal base sequences of DNA by removing a section of DNA and introducing
another gene. The technique may involve the use of the bacterium E. coli. The
bacterium has one large chromosome and several small plasmids, which are
ring-shaped pieces of DNA found in the cytoplasm.
Genetic engineers have been able to extract plasmids from E.coli. Restriction
enzymes are used to cut the DNA of the plasmid at designated places in the
base sequence. The same enzymes are used to cut a section of human DNA.
This section of human DNA is then placed into the space in the cut DNA of the
bacterial plasmid. The human DNA codes for the synthesis of a product such as
human growth hormone. The spliced bacterial DNA, which now contains a piece
of human DNA, is referred to as a hybrid. This hybridized plasmid is then
transplanted into E.coli. When the bacterium reproduces, the hybrid DNA will
replicate. The offspring will possess the ability to synthesize the human growth
hormone
1. What is a bacterial plasmid?
Small, ring-shaped pieces of DNA found in the bacterial cytoplasm.
2. What is a hybrid plasmid?
It is a recombinant plasmid.
A bacterial plasmid that contains a piece of human DNA
3. Explain how genetic engineers remove sections from human DNA for splicing
Into bacterial DNA
Genetic engineers use restriction enzymes to cut the human DNA
and the bacterial plasmid, and insert the human DNA in the bacterial plasmid
4. State one benefit of gene splicing
One benefit of splicing is to produce human hormones, like insulin, growth
hormone, etc… , for sick people
5. Explain why it is not necessary to continue splicing the gene for human growth
hormone into E.coli once cultures of the bacteria with the spliced gene are established
Because the transformed bacteria can be cloned and new bacteria with
the recombinant plasmid
Describe the picture above following the numbered sequence.
Assure to include these terms: restriction enzymes, DNA, plasmid,
gene, recombinant plasmid, replication, cloning, insulin.
Describe the picture above
following the numbered
sequence.
Assure to include these terms:
restriction enzymes, DNA,
plasmid, gene, recombinant
plasmid, replication,
cloning, insulin
1. First, remove the DNA from a human body cell, then isolate the human
gene of insulin using restriction enzymes.
2. Second, remove a plasmid from a bacterium and treated with the same
restriction enzymes.
3. Third, bind the plasmid with the human gene to form a recombinant plasmid.
Then the recombinant plasmid is re-inserted back into the bacterium
4. The recombinant plasmid replicates and a large number of identical bacteria
are cloned. They produce human insulin.