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
The water potential of pure water in an open container is zero because there is no solute and the pressure in the container is zero. Adding solute lowers the water potential. When a solution is enclosed by a rigid cell wall, the movement of water into the cell will exert pressure on the cell wall. This increase in pressure within the cell will raise the water potential.
Look again at the equation for water potential:
Water potential (Ψ) = pressure potential (Ψp) + solute potential (Ψs)
There are two components to water potential: solute concentration and pressure. How do you think this fact affects the movement of water into and out of cells? For example, can two solutions that differ in their solute concentration be at equilibrium in terms of water movement? Can a solution with a molarity of 0.2 be in equilibrium with a solution with a molarity of 0.4?