How Can Gel Electrophoresis Be Used to Analyze DNA?

ANSWERS Process of Science (12.13)

Lab Notebook

Actual Base Pairs (bp) Measured Distance (mm) 23,130 11 9,416 16 6,557 18 4,361 22 2,322 29 2,207 32 564 46

Distance Migrated (mm) Interpolated Fragment Size (in base pairs) Fragment 1 20 4796 Fragment 2 34 1405 Fragment 3 36 1268

Distance Migrated (mm) Interpolated Fragment Size (in base pairs) Fragment 1 17 6201 Fragment 2 36 1268

Questions 1. What is the relationship of migration distance to fragment size?

Migration distance is inversely proportional to the fragment size.

2. Approximately how many base pairs are there in the fragment circled in red at left?

3500

3. Which lane shows a digest with BamHI only?

III ______Campbell/Reece/Taylor/Simon: Biology: Concepts & Connections, Sixth Edition, © Pearson Education, Inc., publishing as Benjamin Cummings 4. Which lane shows a digest with EcoRI only?

5. Which lane shows the fragments produced when the plasmid was incubated with both EcoRI and BamH1?

6. A segment of DNA has two restriction sites—I and II. When incubated with restriction enzymes I and II, three fragments will be formed—a, b, and c. Which of the following gels produced by electrophoresis would represent the separation and identity of these fragments?

______Campbell/Reece/Taylor/Simon: Biology: Concepts & Connections, Sixth Edition, © Pearson Education, Inc., publishing as Benjamin Cummings