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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
Primary productivity is a term used to describe the rate at which plants and other photosynthetic organisms produce organic compounds in an ecosystem. There are two aspects of primary productivity:
- Gross productivity = the entire photosynthetic production of organic compounds in an ecosystem.
- Net productivity = the organic materials that remain after photosynthetic organisms in the ecosystem have used some of these compounds for their cellular energy needs (cellular respiration).
Since oxygen is one of the most easily measured products of both photosynthesis and respiration, a good way to gauge primary productivity in an aquatic ecosystem is to measure dissolved oxygen. We cannot measure gross productivity directly because respiration, which uses up oxygen and organic compounds, is always occurring simultaneously with photosynthesis—but we can measure it indirectly. Let's see how to do this.
- We can measure net productivity directly by measuring oxygen production in the light, when photosynthesis is occurring.
- We can also measure respiration without photosynthesis by measuring O2 consumption in the dark, when photosynthesis does not occur.
- Since net productivity = gross productivity − respiration, we can calculate gross productivity.