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 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 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.

In this hands-on activity, students build a paper model to explore how CRISPR-Cas9 is used to edit genes.

This activity guides the analysis of a published scientific figure from a study that investigated whether there is a correlation between a population’s diet and copies of a certain gene.

This tutorial describes the structure and function of the cancer-causing protein BCR-ABL. It also shows how drugs targeting this protein can help treat chronic myeloid leukemia (CML), a cancer of the white blood cells.

This activity extends concepts covered in the film Got Lactase? The Co-evolution of Genes and Culture. Students infer whether someone is likely to be lactase persistent or nonpersistent based on the data from two different tests.

In this activity, students simulate a lactose tolerance test, similar to the one shown in the short film The Making of the Fittest: Got Lactase? The Co-evolution of Genes and Culture, to determine which samples contain the lactase enzyme.

This animation shows how human infants can digest milk using the enzyme lactase.

This animation shows how proteins in the cell are tagged for disposal by ubiquitin and then degraded by the proteasome.

This interactive, modular lab explores how the ELISA method can be used to test blood samples for evidence of certain diseases.