Absolutely essential for all life on Earth, lipid bilayers are a critical component of all biological membranes, including cell membranes. They are composed of two layers of phospholipids—a class of fat-soluble molecules—positioned such that their hydrophilic, or water-absorbing, heads face outward, and their hydrophobic, or water-repelling, tails face inward, blocking entry of water and water-soluble material into the cell. Why is it important that lipid bilayers are asymmetrical?
Back in the day
Occurring in the midst of the Dominican Republic's turbulent 19th-century history, the 1844 revolt that overthrew French-Haitian rule established an independent republic with a presidency that was, in turns, held by Pedro Santana and Buenaventura Báez. Each president at one point tried to bring stability to the country through foreign rule—the former through Spain and the latter through the US. During what period did the US occupy the island nation and establish a military government there?
Born on a day like today
In 1981, neurobiologist David Hubel and his research partner, Torsten Wiesel, received the Nobel Prize in Physiology or Medicine for their research in visual neurophysiology and their discoveries concerning information processing in the visual system. Their observations of the various nerve impulses and nerve cells responsible for different types of visual stimuli opened the door for the understanding and treatment of what ailments?