Animal eggs consist of only one cell, making them the largest cells produced by a species. The largest cell in the world is the ostrich egg, while female eggs are the largest cell in the human body.
Ostrich eggs can weigh over 3 pounds, but this is tiny compared to the largest egg ever produced by a bird. This record belonged to the elephant bird, which laid eggs up to 15 times larger than ostrich eggs. However, these birds became extinct during the 1600's.
The smallest cell in the human body is the male sperm, which consists of only a nucleus.