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 film explores the foundational research in the Serengeti National Park, Tanzania, that uncovered many of the ecological principles that govern how animal populations and communities are regulated.
In this video, ecologist Brian Silliman explains how he uses manipulative field experiments to study salt marsh ecosystems. His approach revealed that these systems are under top-down control from consumers and predators.