Cell transport
How cells move cargo across membranes and between compartments.
6 problemsMolecular and cell biology
Cells, genes, and the mechanisms that organize living systems.
Explore Molecular and cell biology
Cell growth and division
The coordination of cell size, DNA copying, and chromosome separation.
3 problemsGenetics
Genomes, inheritance, and changes in genetic information.
13 problemsCollections
Browse collectionsOrigins and complexity
From the first living systems to complex cells and multicellular organisms, explore several transitions in life’s history.
10 problemsGenes and development
How do genomes and regulatory systems shape traits, reliable development, and repair?
32 problemsInside cells
Molecular traffic, cell machinery, patterned shells and signals between cells.
14 problemsA few problems to explore
62 totalBiological aging
Cells change, tissues lose resilience and organs age at different rates. Which changes drive the others, and how do they become a whole-body process?
Eukaryogenesis
Complex cells with nuclei descended from simpler ancestors. How did their internal compartments, mitochondria, and distinctive cellular organization come together?
Functions of sleep
Sleep is essential, but why do its benefits require a state in which an animal becomes less responsive to its surroundings?
Evolution of multicellularity
Cells have repeatedly evolved into organisms that live and reproduce together. What turns a group of cells into a coherent evolutionary individual?
Sex chromosome evolution
Some lineages keep the same sex chromosomes for vast spans of time; others replace them repeatedly. Why do their evolutionary paths differ so much?
Neural coding
Neural activity carries information, but which aspects of that activity does the brain actually use? A pattern readable by an analyst need not be the pattern used for behavior.