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
Concept 3: Lipids
Lipids include various biomolecules whose common property is their insolubility in water.
Lipids include a variety of molecular types, such as neutral fats, oils, steroids, and waxes. Unlike other classes of biomolecules, lipids do not form large polymers. Two or three fatty acids are usually polymerized with glycerol, but other lipids, such as steroids, do not form polymers.
Lipids perform many important functions in biological systems, including:
- contributing to the structure of membranes that enclose cells and cell compartments
- protecting against dessication (drying out)
- storing concentrated energy
- insulating against cold
- absorbing shocks
- regulating cell activities by hormone actions
Steroids function both as hormones (such as the sex hormones estrogen and testosterone) and as structural material (such as cholesterol, an integral part of animal cell membranes).