1 - 12 of 85 results
Citric Acid Cycle

This animation shows the reactions of the citric acid cycle, which splits off carbon atoms and generates energy-rich reduced forms of cofactor molecules. It is the first of three animations about cellular respiration.

Electron Transport Chain

This animation shows how the enzyme complexes of the electron transport chain harvest energy from cofactor molecules to pump protons across the mitochondrial membrane and establish a chemical gradient. It is the second of three animations about cellular respiration.

ATP Synthesis

This animation shows how the proton gradient across the mitochondrial membrane powers the ATP synthase enzyme to make ATP. It is the third of three animations about cellular respiration.

Evaluating Science in the News

In this activity, students evaluate a science news article to determine whether it is a trustworthy source of information.

Modeling the Structure of DNA

In this activity, students build a paper model of DNA and use their model to explore key structural features of the DNA double helix. This activity can be used to complement the short film The Double Helix.

Inheritance and Mutations in a Single-Gene Disorder

This activity builds on information presented in the short film Genes as Medicine. Students interpret actual pedigrees to determine the inheritance pattern of Leber congenital amaurosis (LCA), an inherited form of blindness.


This multipart animation series explores the process of photosynthesis and the structures that carry it out.

Developing an Explanation for Tuskless Elephants

This activity builds on information presented in the video Selection for Tuskless Elephants. Students use scientific evidence and reasoning to construct an explanation of and develop an argument for tusklessness in elephant populations.

Understanding Global Change

This interactive module allows students and educators to build models that explain how the Earth system works. The Click & Learn can be used to show how Earth is affected by human activities and natural phenomena.

Cystic Fibrosis Mechanism and Treatment

This animation shows how mutations in an ion channel protein lead to the genetic disease cystic fibrosis. The animation also discusses how research on this protein has been used to develop treatments for the disease.

Using Images as Phenomena

This hands-on activity engages students in asking questions about phenomena using collections of images.