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 short video explores how a baby’s microbiome is established during birth.

This activity guides the analysis of a published scientific figure from a study on how social status affects the expression of genes involved in immune system processes.

This activity analyzes a published scientific figure from a study assessing if the microbiota from a mother affects the immune systems of the developing offspring.

This asynchronous course is designed to deepen educators' content knowledge in evolution, especially regarding content appropriate for teaching at the high school level. 

This demonstration models the first step of the HIV life cycle: the binding of HIV envelope proteins to receptors on human helper T cells.

In this activity, students explore different ways of calculating t-values and performing t-tests using built-in functions in Excel or Google Sheets. Students apply what they learned by plotting beak size measurements of Galapágos finches collected before and after a drought.

In this activity, students explore different ways of constructing a histogram using Excel or Google Sheets. Students apply what they learned by plotting beak size measurements of Galapágos finches before and after a drought.