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 video follows biologist Shane Campbell-Staton, who is studying the adaptations that allow deer mice living at high elevations to stay warm and active during the winter.

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

This activity guides the analysis of a published scientific figure from a study that investigated how salt affects the electron transport chain.

This short video explores how the symbiotic relationship between certain plants and fungi allows these organisms to survive in very hot temperatures.

This activity accompanies the video Seed Dispersal and Habitat Fragmentation. Students use data from published studies to understand patterns of seed dispersal and apply these ideas to the design of a conservation area.

This activity supports the film Popped Secret: The Mysterious Origin of Corn. Students analyze data on the expression of the tb1 gene to explain how variations in this gene played a role in the evolution of corn.

This video follows scientists studying the seeds that brown spider monkeys disperse in a tropical forest of Colombia in order to inform and improve reforestation efforts.

This activity explores images of plant cells and structures, which serve as phenomena for learning about how plants respond to stimuli.

This activity guides the analysis of a published scientific figure from a study on prehistoric human food sources. In this study, scientists used carbon isotopes to determine how the advent of agriculture affected human diets.