prometaphase. Prometaphase is the second phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prometaphase, the physical barrier that encloses the nucleus, called the nuclear envelope, breaks down. The breakdown of the nuclear envelope frees the sister chromatids from the nucleus, which is necessary for separating the nuclear material into two cells.
The Sistine Chapel ceiling, painted by Michelangelo between 1508 and 1512, is a cornerstone work of High Renaissance art. The ceiling is that of the Sistine Chapel, the large papal chapel built within the Vatican between 1477 and 1480 by Pope Sixtus IV, for whom the chapel is named. It was painted at the commission of Pope Julius II. The chapel is the location for papal conclaves and many other important services.
The Sistine Madonna. The Sistine Madonna is one of Raphael's most famous works. The painting takes it's name from the church of San Sisto in Piacenza and Raphael painted it as the altarpiece for that church in 1513-1514. The piece was purchased in 1754 by King Augustus III of Saxony for his collection in Dresden.