Related topics: protein · cancer cells · cancer · stem cells · immune system

Ebola: Scientists reveal a new way it replicates

Scientists in Canada and the U.S. have discovered a new way in which Ebola—an often deadly virus affecting people mostly in sub-Saharan Africa—reproduces in the body.

Why eukaryotes, not bacteria, evolved complex multicellularity

Prokaryotic single-celled organisms, the ancestors of modern-day bacteria and archaea, are the most ancient form of life on our planet, first appearing roughly 3.5 billion years ago. The first eukaryotic cells appeared around ...

Gene expression technology set to semi-automation

The Human Genome Project generated the first sequence of the human genome, revealing a kind of blueprint of human biology. Two decades later, the field of gene regulatory networks describes a complex system where thousands ...

Flying first on Ariane 6

With Europe's new Ariane 6 rocket now at its spaceport in French Guiana, the passengers it will launch to space are getting ready to be added to the top of the tall new rocket. Ariane 6 will launch several satellites, deployers ...

page 1 from 4

Cell (biology)

The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.

In 1835 before the final cell theory was developed, a Czech Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biological structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.

This text uses material from Wikipedia, licensed under CC BY-SA