Pearson, as an active contributor to the biology learning community, is pleased to provide free access to the Classic edition of The Biology Place to all educators and their students.
The purpose of the activities is to help you review material you have already studied in class or have read in your text. Some of the material will extend your knowledge beyond your classwork or textbook reading. At the end of each activity, you can assess your progress through a Self-Quiz.
To begin, click on an activity title.
Lab 2 Enzyme Catalysis
Mitosis and Meiosis
Plant Pigments and Photosynthesis
6-I Bacterial Transformation
6-II DNA Electrophoresis
Genetics of Organisms
Population Genetics and Evolution
10-I Cardiovascular Fitness
10-II Heart Rate in Daphnia
Biomembranes I: Membrane Structure and Transport
Biomembranes II: Membrane Dynamics and Communication
Cardiovascular System I: The Beating Heart
Cardiovascular System II: The Vascular Highway
Cell Structure and Function
DNA Structure and Replication
From Gene to Protein: Transcription
From Gene to Protein: Translation (Protein Synthesis)
Plant Structure and Growth
Properties of Biomolecules
Restriction Enzyme Digestion of DNA
The lac Operon in E. coli
Key Concepts II: Electrophoresis
In the 1960s, scientists discovered that bacteria have enzymes that cut, or "digest," the DNA of foreign organisms and thereby protect the cells from invaders such as viruses. Scientists have now isolated several hundred of these enzymes, known as restriction enzymes, or restriction endonucleases. Each is able to recognize and cut at a specific DNA sequence, known as a recognition sequence.
The discovery of restriction enzymes made genetic engineering possible because researchers could use them to cut DNA into fragments that could be analyzed and used in a variety of procedures.
In this part of the laboratory, you will use gel electrophoresis to separate samples of DNA that have been digested by restriction enzymes. Then you will compare fragments of unknown size to fragments of a known size to calculate the unknown fragment sizes.
Let's begin by looking at how restriction enzymes work.