Single-molecule analysis using super-resolution microscopes reveals that transcription factors are not usually found bound to their binding sites on DNA.
Zoom into a coral reef and discover photosynthetic algae inside the coral’s cells. Reef-building corals rely on these symbionts for their survival.
Disrupting the normal processes of differentiation and maturation of the intestinal epithelial cells can lead to cancer.
Genes associated with autism affect the structure and function of neuronal synapses.
Most of the neurons of the cerebral cortex arise from progenitor cells that undergo repeated cell division.
This animation features the anole lizards as an example of how a single species can split and multiply into many different species with distinct traits.
Mutations in the BCR-ABL gene can cause resistance to Gleevec, but another drug, dasatinib, can be used instead.
The drug Gleevec binds to and inactivates BCR-ABL, a mutant kinase that causes chronic myeloid leukemia.
A mosquito becomes infected with malaria when it sucks the blood from an infected human. Once inside the mosquito, the parasites reproduce in the gut and accumulate in the salivary glands, ready to infect another human host with the next bite.
When a malaria-carrying mosquito bites a human host, the malaria parasite enters the bloodstream, multiplies in the liver cells, and is then released back into the bloodstream, where it infects and destroys red blood cells.
View the animation to see how one type of immune cell—the helper T cell—interprets a message presented at the surface of the cell membrane. The message is an antigen, a protein fragment taken from an invading microbe. A series of events unfolds that results in the production of many clones of...
Plate tectonics is the unifying theory of Earth science.
Arctic sea ice melted on an unprecedented scale in 2012, opening up the fabled Northwest and Northeast passages.
CO2 emitted by volcanoes into the atmosphere is removed by a...
Sunlight that warms Earth is re-emitted as infrared radiation, which is absorbed by greenhouse gases and causes further warming.
An early continental drift model proposed that mantle convection can produce continental movement and new plate formation.
An early model of continental drift proposed that parts of continental plates can sink into the mantle, allowing for movement.
The breakup of a supercontinent into several smaller continents explains the distribution of fossil and geologic evidence.
Reconstructing past continental plate movements reveals the island of Spitsbergen was tropical 500 million years ago.
Environmental and cultural factors can affect whether a new human mutation becomes common in a population.
The lactase enzyme is produced in the small intestine of infants. It digests lactose by breaking it into glucose and galactose.
General transcription factors, activators, and repressors interact to regulate the transcription of eukaryotic DNA into RNA.
Infection begins when the dengue virus uses receptors on an immune cell's surface to gain entry and release its genome.
The dengue virus's outer envelope proteins form symmetrical units and overlay the lipid envelope, capsid, and the RNA genome.
Since the 1960s dengue fever has spread to many countries and total case numbers have exploded.