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.
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.
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.
This activity guides the analysis of a published scientific figure from a study that explored the evolutionary origins of parasitic beetles that mimic army ants.
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.
In this activity, students engage with an example from the Serengeti ecosystem to illustrate the exchange of nutrients between plants, animals, and the environment.
This activity guides the analysis of a published scientific figure from a study that investigated how gene duplication contributed to the evolution of electric fish.
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.
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.