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Materials:
-
70% or higher
percentage ethanol ,chilled overnight in a freezer
-
Shampoo
Fructis
-
Laundry
detergent Ariel
-
Dishwashing Liquid Quix
-
Balance
-
1 500 mL
beaker
-
Six 200
mL graduated beakers
-
One 100
mL beaker
-
Six
Large kiwi fruits
-
Knife
and fork for cutting and mashing
-
Cutting
board
-
Three
funnels
-
Three
thermometers
-
Ice
-
Filter
paper
-
Cold
water
-
Six
glass stirring rods
-
Hot tap
water (60°C)
-
Two
saucepans or other large containers for water baths
-
Table
salt (NaCl)
-
Six test
tubes
-
Test
tube rack
-
Twelve
sterile eye droppers
-
Hot
plate
-
Chronometer
-
pH paper
Procedure:
Verifying the pH of the detergents:
1.
Using the pH paper Measure the degree of alkalinity of the three detergent.
Use the color scale provided to interpret the results.
Liberating the DNA:
1. Prepare
an ice water bath by putting ice and water into a saucepan or similar
container to a depth of 5 to 8 cm. Put about 50 mL of chilled ethanol into
the 100-mL beaker and place the beaker in the ice bath.
2. Prepare the
DNA extraction solution. Dissolve 2 g of salt in 90 mL of water in a 200-mL
beaker. Then add 10 mL of detergent and stir with a glass stirring rod
3. Peel the
kiwi fruit over waxed paper or a paper plate and cut it into chunks.
4. Use a
balance to measure 30 g of kiwi chunks, then thoroughly mash that amount
with a fork.
5.
Place the mashed kiwi in a 200-mL beaker.
6. Pour 15
mL of the
DNA extraction solution over the fruit.
7. Prepare a hot
water bath by putting hot water into a saucepan about 5 to 8 cm deep. Check
the temperature of the hot water bath with the thermometer. Add colder or
hotter water to get the water to 50°C. If you have a hot plate, put the
water bath on it to help it reach and maintain a 50° temperature. Check the
temperature periodically and adjust as needed.
8. Place
the beaker with fruit and extraction solution into the hot water bath. Note
the time.
9. Let the
fruit and extraction solution mixture incubate in the hot water bath for 10
to 15 minutes. Stir the solution occasionally to distribute the heat.
The temperature of the water bath must be monitored and maintained at 50°C
during this incubation period.
10. After 10 or 15
minutes of incubation, transfer the beaker containing the fruit and
extraction solution mixture to the ice bath. Allow it to stay there
for 5 minutes, stirring occasionally as it cools.
11. While the
extraction mixture is cooling, set up the filtration system. Place a funnel
over a clean 200-mL beaker, and insert a coffee filter into the funnel.
12. Pour the cooled
extraction mixture into the filter-lined funnel. Allow the liquid to filter
for about 5 minutes.
13.
Thoroughly swirl the filtrate.
14.
Pour 5 mL of the filtrate into a test tube.
Precipitating the DNA
1. Gently
layer 10 mL of cold ethanol on top of the filtrate. You can add the
ethanol with a dropper or gently pour it down the side of the test tube
while you hold it at an angle.
2. Place
the test tube in the ice bath. Observe what's happening in the test tube at
the area where the ethanol and filtrate layers meet. Record your
observations.
3. Let the
solution sit for 5 minutes without disturbing it. A white precipitate will
form in the alcohol layer. This is the DNA, and it will appear as a slimy,
white mucus.
4. Collect the DNA with
an dropper at the ethanol/filtrate interface.
Calculating the amount extracted:
1. Weigh the pieces of
filter paper
2.
Use an eye dropper to
place the DNA you extracted on these pre weighted filter paper pieces.
Spread the DNA as much as possible; it will dry more slowly when it is
clumped.
3.
Let the DNA sit for
several days until you are sure it is absolutely dry.
4.
Weigh the filter paper
again with the DNA
5.
Calculate
the DNA weight.
Comparing the Efficiency:
1.
Repeat the
entire procedure of DNA extraction using different detergents during the
process.
2.
Compare the results.
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