Allele frequencies in populations and how they differ from genotype frequencies. Created by Sal Khan.

Using the Hardy-Weinberg equation to calculate allele and genotype frequencies. Created by Sal Khan.

Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms. For the particular model they work on, they isolate a mammal insulin gene and combine it with a bacteria's gene sequence (plasmid DNA) for production of the protein insulin.

Students toss coins to determine what traits a set of mouse parents possess, such as fur color, body size, heat tolerance, and running speed. Then they use coin tossing to determine the traits a mouse pup born to these parents possesses. Then they compare these physical features to features that would be most adaptive in several different environmental conditions. Finally, students consider what would happen to the mouse offspring if those environmental conditions were to change: which mice would be most likely to survive and produce the next generation?

This exercise contains two interrelated modules that introduce students to modern biological techniques in the area of Bioinformatics, which is the application of computer technology to the management of biological information. The need for Bioinformatics has arisen from the recent explosion of publicly available genomic information, such as that resulting from the Human Genome Project.

This 28-minute video lesson provides an introduction to DNA. [Biology playlist: Lesson 6 of 71].

This 17-minute video lesson provides an introduction to heredity and classical genetics. It looks at dominant and recessive traits as well as heterozygous and homozygous genotypes. [Biology playlist: Lesson 14 of 71].

This 25-minute video lesson looks at the Punnett square diagram in the study of genetics. It covers dihybrid crosses, independent assortment, incomplete dominance, codominance and multiple alleles. [Biology playlist: Lesson 15 of 71].

This learning video introduces high school students to a topic they would not ordinarily study in school, biotechnology, and to different applications of biotechnology that relate to the main theme of the module - making the desert greener. After reviewing traditional methods used for manipulating plants to produce desired traits, students will learn about the methods of making transgenic plants. Dr. Ziad discusses a real world problem that is critical in his country, Jordan, where much of the land is desert. A prerequisite to this video lesson is some background in biology.

Overview of how chromosomes were first proposed as the carriers of Mendel's "heritable factors" (what we now call "genes").

All living beings are made up of cells. Some of them are made up of only one cell and others have many cells. Also in: Dutch | French | Hungarian | Spanish

Submitted as part of the California Learning Resource Network (CLRN) Phase 3 Digital Textbook Initiative (CA DTI3), CK-12 Foundation’s high school Biology FlexBook covers cell biology, genetics, evolution, ecology, botany, zoology, and physiology. This digital textbook was reviewed for its alignment with California content standards.

CK-12’s Life Science delivers a full course of study in the life sciences for the middle school student, relating an understanding of the history, disciplines, tools, and modern techniques of science to the exploration of cell biology, molecular biology, genetics, evolution, prokaryotes, protists,fungi, plants, animals, invertebrates, vertebrates, human biology, and ecology. This digital textbook was reviewed for its alignment with California content standards.

CK-12’s Life Science delivers a full course of study in the life sciences for the middle school student, relating an understanding of the history, disciplines, tools, and modern techniques of science to the exploration of cell biology, genetics, evolution, prokaryotes, protists, fungi, plants, the animal kingdom, the human body, and ecology. This digital textbook was reviewed for its alignment with California content standards.

The topic of this video module is how to classify animals based on how closely related they are. The main learning objective is that students will learn how to make phylogenetic trees based on both physical characteristics and on DNA sequence. Students will also learn why the objective and quantitative nature of DNA sequencing is preferable when it come to classifying animals based on how closely related they are. Knowledge prerequisites to this lesson include that students have some understanding of what DNA is and that they have a familiarity with the base-pairing rules and with writing a DNA sequence.

What is cloning and do we have clones living among us today? The answers might surprise you or maybe we should say ewe.

Students reinforce their knowledge that DNA is the genetic material for all living things by modeling it using toothpicks and gumdrops that represent the four biochemicals (adenine, thiamine, guanine, and cytosine) that pair with each other in a specific pattern, making a double helix. They investigate specific DNA sequences that code for certain physical characteristics such as eye and hair color. Student teams trade DNA "strands" and de-code the genetic sequences to determine the physical characteristics (phenotype) displayed by the strands (genotype) from other groups. Students extend their knowledge to learn about DNA fingerprinting and recognizing DNA alterations that may result in genetic disorders.

Students perform DNA forensics using food coloring to enhance their understanding of DNA fingerprinting, restriction enzymes, genotyping and DNA gel electrophoresis. They place small drops of different food coloring ("water-based paint") on strips of filter paper and then place one paper strip end in water. As water travels along the paper strips, students observe the pigments that compose the paint decompose into their color components. This is an example of the chromatography concept applied to DNA forensics, with the pigments in the paint that define the color being analogous to DNA fragments of different lengths.