Unicellular

(adjective. /yoo-nih-SELL-yoo-ler/)

by Amy Aponte

What does it mean? 

A unicellular organism is made of only one cell. Inside this single cell, these organisms carry out all of the necessary life processes (such as digestion, excretion and reproduction). Unicellular organisms include bacteria, archaea, protists, and yeast. 

How do I use it in a sentence?

“We looked at unicellular bacteria under the microscope in Biology class. ”

Microscope image showing E.coli bacteria. Each rod shape that you see is one single, unicellular organism.  Image source
While some unicellular organisms are only visible under a microscope, some are visible to the naked eye. The image above shows one of the largest unicellular organisms in the world, the amoeba called slime mold. You can read more about this amoeba and other big unicellular organisms here. Image source

Etymology

The prefix uni- means one. So, “unicellular” means “one cell”.

Related terms

Unlike unicellular organisms, multicellular organisms are made of many cells. All animals, including yourself, are multicellular organisms. 

Fields of study in which this word is commonly used

Biology 
Ecology

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