What Is The Largest Cell In The World? For Kids

The short answer

It depends what you mean. The biggest animal cell is the yolk of an ostrich egg, before a chick starts to grow. The biggest single-celled living things are seaweeds: Valonia ventricosa, called sailor's eyeball, is one cell you can hold in your hand, and Caulerpa taxifolia is one cell with runners longer than your arm. In the human body, the biggest cell is the egg cell and the longest is a nerve cell a meter or more long.

The Long Answer

Most of your cells are tiny, between about 7 and 100 micrometers across: far too small to see without a microscope. A few living things break the rule.

The Biggest Animal Cell

A bird's egg yolk, before a chick starts to grow, is a single cell: an egg cell packed with food. The ostrich lays the biggest eggs of any living bird, so its yolk is the biggest cell of any living animal.

One Cell You Can Hold

Valonia ventricosa grows in warm, shallow seas. It looks like a dark green marble, usually 1 to 3 centimeters across and sometimes as big as 5, and the whole thing is one cell. Divers call it sailor's eyeball.

One Cell Longer Than Your Arm

Caulerpa taxifolia is a seaweed with what look like stems, fronds and roots, yet it is one enormous cell with many nuclei inside it. Its fronds grow 15 to 30 centimeters long and its runners can stretch past a meter. One scientific paper calls it debatably the largest single-celled organism, which is as sure as anyone can be.

In The Human Body

The human egg cell is the biggest, about a tenth of a millimeter across. The longest are nerve cells: some run from your lower back all the way to your big toe, a meter or more long in a grown-up. A grown-up is made of about 30 to 37 trillion cells; a 10-year-old, about 17 trillion.