EDVOTEK 104 Size Determination of DNA Restriction Fragments
IMPORTANT: SAVE THIS DOCUMENT WITH YOUR NAME TO YOUR COMPUTER.
Name _____________________
Analyzing Results
1. In this procedure a Standard DNA containing 9 fragments of known sizes was run with 2 unknown
samples.
2. Compare the results from the class with the pictures below which illustrate the results we should
have obtained. You may want to save the pictures from our website to your desk top and rotate
them so you can more easily compare them.
a. How many bands could you see on our standard?
b. What would explain why we did not get the same results as the manufacturer?
3. I have performed a best estimate in determining the travel length of each band. To determine the
size of the unknown fragments Standard curve must be created. Use information and charts in the
article “Estimating Sizes of DNA Bands by Semi-Log Plot” (on web page) to plot the results of the
Standard and determine the size of the unknowns.
Sample
Millimeters Traveled
Size in base pairs
15
23130
24
9416
30
6557
42
7361
55
3000
72
2322
75
2027
87
725
94
570
Unknown A
23
Unknown B
27
Unknown B
39
4. Use your Standard Curve to answer the following two questions:
a. If you had a sample which traveled 50 mm how many base pairs would you expect the
sample to contain?
b. If you had a sample hat contained 3500 base pairs how many millimeters would you expect
it to travel.
EDVOTEK 104 Size Determination of DNA Restriction Fragments
YOUR NAME ________________________________
Study Questions
1.
2.
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6.
Define “restriction enzymes”.
State the reason restriction enzymes are an important tool in analyzing unknown DNA samples.
State the size range for DNA fragments which can be analyzed by electrophoresis.
State the electrical charge of DNA fragments.
How does agarose gel allow determination of the size of DNA fragments?
Describe the size of DNA fragments found closest to the point of application to those found
farthest from the point of application.