Download Biotechnology

Chapter 20: Biotechnology
The questions, readings, simulations, and activities contained herein are meant to familiarize you
with key biotechnology terminology and practices that could be covered on the AP biology
exam. The benefit and understanding you gain from these assignments will be commensurate
with the level of effort you put into completing the work. Some class and laboratory time may
be devoted to exploring specific biotechnology concepts, however, you are responsible for
completing all the work contained in this packet. A summative assessment will follow your
completion of this packet to test your knowledge about biotechnology.
Overview
This packet is organized into the following content areas:
1.
2.
3.
4.
5.
6.
7.
8.
What is biotechnology?
Restriction Enzymes
Plasmid-based Transformation
Polymerase Chain Reaction (PCR)
Gel Electrophoresis
Genetically modified organisms (GMOs) – plants and animals
Cloning
Pharmaceuticals (insulin)
1. What is Biotechnology?
Biotechnology - the manipulation (as through genetic engineering) of living organisms or their
components to produce useful usually commercial products (as pest resistant crops, new bacterial
strains, or novel pharmaceuticals); also: any of various applications of biological science used in
such manipulation.
It is important to understand the meaning of the three terms in bold to start this chapter.
Please define.
recombinant DNA -
genetic engineering -
gene cloning -
1
2. Restriction Enzymes
Read the description of restriction enzymes on page 398 carefully. Label the diagram below
and write the 3 steps involved to make recombinant DNA.
Questions to consider related to restriction enzymes:
a. Why do DNA molecules always yield the same set of restriction fragments when exposed
to the same restriction enzymes?
b. When a DNA fragment has been removed by restriction enzymes why are the ends on the
fragment and the original DNA called “sticky”? Explain.
c. What enzyme permanently joins a fragment from one DNA molecule to another forming
recombinant DNA? What other role does this enzyme play in DNA replication?
2
d. Predict why restriction enzymes play such an important role in gene cloning.
e. The restriction site for an enzyme called PvuI is the following sequence:
5’-CGATCG-3’
3’-GCTAGC-5’
Staggered cuts are made between the T and C on each strand. What type of bonds are
being cleaved?
f. One strand of a DNA molecule has the following sequence: 5’CCTTGACGATCGTTACCG-3’. Draw the other strand. Will PvuI cut this molecule?
If so, draw the products.
3. Plasmid-based transformation
Look at Figure 20.4 on page 399 of your textbook. This is a more detailed discussion of the gene
cloning procedure shown in figure 20.2 of your text. The questions that follow pertain to how a
bacterium can be used to clone genes of interest from another organism.
Please define:
Plasmid -
Cloning VectorBacterial transformation –
a. Explain why the plasmid is engineered with ampR and lacZ?
b. After transformation has occurred why are some colonies blue?
3
c. Why are some colonies white? Why is this important?
d. Why does the lacZ gene not work properly in the recombinant plasmids?
e. What benefits are realized by researchers when genes can be easily cloned using
plasmids?
Plasmid transformation for producing transgenic organisms
Transgenic organism – organisms that contain genes from other species produced by insertion
of recombinant DNA into the genome of a host organism
Transgenic Plants – transformed by using bacteria such as Agrobacterium tumefaciens,
removing the cell wall or directly injected
Transgenic Animals – transformed by injecting DNA directly into the nucleus of egg cells.
Read the description of Genetic Engineering in Plants on page 421 and 422 in your textbook.
Label Figure 20.25 below and write the 3 steps involved to make a transgenic plant.
Step 1 -
Step 2 -
Step 3 -
4
Now, make your own transgenic plant. Follow the link below and follow the directions to make
a transgenic tomato plant that is both herbicide and pest resistant.
PBS - Transgenic Manipulation
Answer the questions below pertaining to the simulation:
1. What is Bt and where did it come from?
2. What transgenic properties will your tomato plant have?
3. What do you think the “vector” is in the simulation?
4. Although not shown what other gene was added to the vector?
5. How did the Bt gene and herbicide resistance gene get incorporated into the genome of
the tomato plant cells?
6. In this simulation how was it confirmed that the plant cells have taken up the desired
genes?
7. Explain from a practical standpoint how this tomato plant would increase a farmers yield
(your tomato seed would be called a “stacked” variety because it is modified in two
ways).
8. Imagine you are the biotechnology company that developed this transgenic tomato plant,
what risks do you face after the seeds are sold and how will you protect your technology?
4. Polymerase chain reaction (PCR)
PCR is a Nobel Prize–winning idea that is used by scientists to amplify DNA, particularly when
the quantity of DNA is very small or contaminated. PCR is discussed on pages 403 and 404 of
your textbook.
Use the following link to watch the 3D and 2D animation of PCR in action under the heading
“Technique”:
5
Polymerase Chain Reaction (PCR) Collection: DNA Learning Center
a. Explain the three initial steps that occur in cycle 1 of PCR (use figure 20.8).
b. According to your text what was the “key” to automating PCR?
c. How many cycles does it take to get the actual target sequences of DNA made?
d. What four “ingredients” must be brought together in the reaction to make sure that PCR
works?
e. What biotechnology process discussed earlier in this assignment could be bypassed if
PCR were used instead?
5. Gel Electrophoresis
Gel Electrophoresis was commonly called “DNA Fingerprinting”. Bear in mind that this
technique has nothing to do with actual fingerprints, although it could be used to analyze DNA
samples from a crime scene and potentially identify or rule out a possible suspect. This type of
analysis is now called “DNA profiling” or “DNA testing”.
Use the link below to conduct your own virtual Gel Electrophoresis analysis:
University of Utah - Gel Electrophoresis
Questions from simulation.
a. Scientists use gel electrophoresis to sort DNA according to what factor?
b. Why is the DNA sample to be separated by gel electrophoresis always loaded at the
cathode or negative end of the power source?
c. Shorter strands will move faster or slower through the gel?
d. Why is a salt water solution used to make the gel and used as a buffer in the gel box?
e. Why is a loading buffer used in combination with the actual DNA samples?
f. What provides the proof that electrical current is actually running through your gel and
buffer?
6
g. What are the DNA bands in the gel stained with so that they can be seen, and what type
of light will they be exposed to?
h. What does bp stand for? Record your DNA sample bp estimates here: ___________
_____________
_____________
Additional Questions:
How did the DNA sample get cut into fragments to be separated by gel electrophoresis in the
first place?
If our DNA is 99.9% the same from one human to the next, why would DNA profiling work to
distinguish one person’s DNA from another? Explain. (hint: check out “Can DNA Demand a
Verdict” link under the simulation)
What are short tandem repeats (STRs) and how are they used in DNA profiling?
Use your text page 406 for this question:
To the right of the β-globin alleles, draw a gel showing the different pattern obtained from a
normal patient and a sickle-cell patient. For help, examine Figure 20.10 from your text.
7
Complete the flowchart about how DNA fingerprints are made.
Restriction
are used to cut the DNA into fragments
containing genes and repeats.
The restriction fragments are separated according to size using gel
.
The DNA fragments containing repeats are then labeled using
radioactive
. This labeling produces a series of
bands—the DNA fingerprint.
Study the DNA fingerprint below. Which two samples may be from a set of identical twins? How
do you know?
8
6. Genetically Modified Organisms (GMO) - plants and animals
Have you eaten genetically modified (GM) foods this week? Probably. The majority of GM
organisms that contribute to our food supply are not animals, but crop plants.
GM Crops – transgenic plants that resist pests, herbicides, disease and result in increased yields.
-Use of these crops is on the rise
-Introduced in 1996 (Round Up resistant soybean)
-As of 2014 GM crops made up 94% of soybeans, 96 % of cotton and 93% of corn
Examples: Roundup ready soybeans, Bt corn, tomatoes, rice, and potatoes
Pick one of the GM plants below and do some research related to the following:
1. What makes it GM/transgenic?
2. What other organism was used as a source of the inserted/manipulated gene?
3. What process is commonly used to accomplish the modification?
4. What benefits does the transgenic plant promise or deliver?
5. Are there any concerns or drawbacks associated with using the GMO?
List of plant GMOs:
Herbicide tolerance – soybeans
Insect resistance – corn
Altered fatty acid composition – canola
Vitamin Enrichment – rice
Vaccines – tobacco
Oral vaccines - maize
Record your answers to the questions above below:
1.
2.
3.
9
4.
5.
GM animals – engineered to increase production, nutritional benefit or product not typically
associated with that animal.
30% of milk in US is coming from cows injected with bovine growth hormone (BGH)
Examples of GM foods from animals:
-Cows – rBGH, increased milk output
-Pigs – leaner meat, omega 3 fatty acids
-Goats – spider genes to manufacture silk, antibacterial goat milk, proteins, drugs
-Salmon – growth hormone, shorter time to market
Aqua Bounty Farms - GM Salmon – use this link to watch a short video about Aqua Bounty and
their 25 year fight to get their genetically modified salmon approved by the FDA. Please answer
the questions below:
a. What other fish was used to make the Atlantic salmon transgenic?
b. What does the gene from the other fish change about the Atlantic salmon?
c. If the transgenic salmon doesn’t grow bigger overall what is the advantage claimed by
Aqua Bounty?
d. What is the “good genes” hypothesis mentioned by the researcher?
e. Why does the Aqua Bounty claim that even if a GM salmon were to escape from a fish
pen at sea that it would have no impact on wild salmon populations?
10
AquaBounty's salmon (rear) have been genetically modified to grow to market size in about half the
time as a normal salmon — 16 to 18 months, rather than three years.
The rest of the story: Genetically Modified Salmon Is Safe to Eat, FDA Says: NPR
Follow the link above and read through the latest news about GM salmon.
Write one paragraph below about your opinion on the issue of GM salmon. What points
do you agree with, what do you disagree with? Would you personally eat salmon that is
transgenic? What are the possible benefits of GM salmon as a food source for others
around the world? Are you concerned about possible ecological threats?
11
7. Cloning
Clones are organisms that are exact genetic copies of each other. This can happen naturally as in
the case of identical twins or artificially using laboratory techniques. Organismal cloning is the
practice of cloning whole multicellular organisms from single cells. Current interest in
organismal cloning has been generated because of the potential to generate stem cells.
Let’s examine organismal cloning methods before exploring types of stem cells. Follow the link
below to the University of Utah’s cloning web page.
University of Utah – Cloning
Click on the tab “What is Cloning?”
Two types of cloning are discussed on this page. Before describing both types of cloning, what
was the most famous animal cloned, and in what year was it cloned?
Briefly summarize each method of organismal cloning in the space below:
Embryo Twinning-
Somatic Cell Nuclear Transfer-
Complete the diagram below that details the cloning of a sheep.
12
Please return to the Univ. of Utah cloning website and click on “Click and clone”, here you will
simulate the cloning of a mouse named Mimi. Work through the simulation to become familiar
with the process.
Again, return to the Univ. of Utah cloning website and click on “Why Clone?”
List the six way that cloning may be useful.
a. ________________________
b. ________________________
c. ________________________
d. ________________________
e. ________________________
f. ________________________
Briefly explain the medical reasons for cloning.
Give at least two reasons why a clone might not be a carbon copy of the donor organism.
What are some barriers to human cloning, both technical and ethical?
Use your text to answer the following questions (pgs. 412-416)
1. What is a totipotent cell?
2. What are stem cells?
3. What is the difference between embryonic stem (ES) cells and adult stem cells?
13
4. What are pluripotent cells?
5. Why might induced pluripotent stem cells (iPS) resolve the debate about using stem cells
for medical treatments?
8. Pharmaceuticals (insulin)
The pharmaceutical industry has been revolutionized by advances in biotechnology. The last
part
of this assignment involves you completing a case study from the National Center for Case Study
Teaching in Science. The case study is entitled From Cow Juice to a Billion Dollar Drug, with
Some Breakthroughs in Between. This case chronicles the science and methodology involved in
identifying and manufacturing insulin for the treatment of type I diabetes.
14