The UK's most valuable monument is deemed to be the 1,000-year-old Tower of London, which is worth an estimated Â£56billion to the British economy and came it at number five in the list of European list. Its value is six times more than its nearest rival the Colosseum in Rome, which is valued at Â£72billion.
Cell cycle checkpoints are control mechanisms in eukaryotic cells which ensure proper division of the cell.
As in both G1 and G2, there is a Checkpoint in the middle of mitosis (Metaphase Checkpoint) that ensures the cell is ready to complete cell division. Actual stages of mitosis can be viewed at Animal Cell Mitosis. Cancer cells reproduce relatively quickly in culture.