egg
The cells you have learned about so far are much smaller than the period at the end of this sentence, so they are normally measured on a very small scale. The smallest prokaryotic cell currently known has a diameter of only 400 nm. Eukaryotic cells normally range between 1 100m in diameter. The mouse cells in Figure above are about 10 m in diameter. One exception, however, is eggs . Eggs contain the largest known single cell, and the ostrich egg is the largest of them all. The ostrich egg in Figure above is over 10,000 times larger than the mouse cell.