DNA is tightly packed in the nucleus of every cell. DNA wraps around special proteins called histones, which form loops of DNA called nucleosomes. These nucleosomes coil and stack together to form fibers called chromatin. Chromatin in turn forms larger loops and coils to form chromosomes.
This engaging animation shows how human skin cells produce the pigment melanin, which gives skin its color.
Disrupting the normal processes of differentiation and maturation of the intestinal epithelial cells can lead to cancer.
Zoom into a coral reef and discover photosynthetic algae inside the coral’s cells. Reef-building corals rely on these symbionts for their survival.
The inner cell mass (ICM) cells of blastocyst-stage early human embryos can be removed and cultured. These cells can be grown in the lab indefinitely. Various growth factors cause these cells to develop into a variety of differentiated cells, such as muscle or nerve cells.
Infection begins when the dengue virus uses receptors on an immune cell's surface to gain entry and release its genome.
This animation describes two different ways by which chemicals migrate through membranes: passive diffusion and active transport.
Watch this animation to see the molecular tricks that an infectious strain of Escherichia coli uses to infect your gut.
Myosin II is one of the molecules involved in furrow formation in dividing cells. This animation shows how the molecule operates, and how furrowstatin blocks the mechanism and halts division of a cell.
In mammals, the controlling clock component that generates a 24-hour rhythm is the suprachiasmatic nucleus (SCN), located in a part of the brain called the hypothalamus. The SCN produces a signal that can keep the rest of the body on an approximately 24-hour schedule. This animation illustrates...
A 3D animation showing how proteins in the cell are tagged for disposal and degraded by the proteasome.
This animation shows how a growing tumor can recruit nearby blood vessels in order to gain a supply of blood.
This animation shows how the random deactivation of one of the X chromosomes in a pair can lead to a mozaicism in the expression genes.