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
Chi-Square Analysis of Data
Look at the tables you printed from Case 1. From the data presented, you can deduce that the F1 cross was between individuals heterozygous for eye color:
+se x +se (+ = red; se = sepia ). From this conclusion, you could write the following hypothesis: "If the parents are heterozygous for eye color, there will be a 3:1 ratio of red eyes to sepia eyes in the offspring." Do your results support this hypothesis?
The actual results of an experiment are unlikely to match the expected results precisely. But how great a variance is significant? One way to decide is to use the chi-square (χ2) test. This analytical tool tests the validity of a null hypothesis, which states that there is no statistically significant difference between the observed results of your experiment and the expected results. When there is little difference between the observed results and the expected results, you obtain a very low chi-square value; your hypothesis is supported.
Next we'll see how to calculate and interpret chi-square. If you would like some help on calculating expected results first, take a side trip before continuing.