Sperm and egg cells, or gametes, are unusual. Egg cells are some of the largest cell types, and sperm are some of the smallest. In humans, these haploid cells come together to form diploid cells. It's ...

The cellular mechanisms that allow the fusion of sperm cells and egg cells originated three billion years ago in unicellular archaea – single-celled organisms that lack a nucleus – according to a ...

Just call them archaea (ar-kee-uh) - archaebacteria are no more. Archaea were once considered to be quite similar to bacteria, but these prokaryotes are just weird enough to be classified in their own ...