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Online Chemistry Labs | Learning Objectives

Background:

This experiment introduces students to the hydrolysis of strawberry DNA to produce nucleobases. Thin layer chromatography is used as a means of determining which nucleobases are freed during the controlled hydrolysis. After a discussion of the primary, secondary, and tertiary structure of DNA and a brief introduction to the principles of TLC methodology, the student tests the raw DNA sample before and after heating the sample in an oil bath, after adding acid to the sample, and after heating again. The student makes runs of each of the samples side-by-side with known nucleobase standards, recording the Rf factors for each case. The student will identify the freed bases in each situation, and is asked to draw conclusions about the appearance of new features.

DNA Hydrolysis

Learning Objectives:

  1. Become familiar with the structures of DNA and nucleobases.
  2. Become familiar with the methodology and practice of TLC.
  3. Learn how to use the Rf factor by measuring spot movement on developed plates.
  4. Be able to compare Rf factors from runs with knowns with values for unknown runs.
  5. Be able to subject a DNA sample to processing with heating and acid hydrolysis.
  6. Be able to answer questions about the method and account for new observations.