Engineering

A new era in 3-D printing

In the mid-15th century, a new technology that would change the course of history was invented. Johannes Gutenberg's printing press, with its movable type, promoted the dissemination of information and ideas that is widely ...

Automotive

Mercedes want to abandon combustion engines by 2039

German giant Mercedes-Benz said Monday it wants to stop selling traditional combustion engine cars by 2039 and plans for its new vehicles sold worldwide by that time to be carbon-neutral.

Energy & Green Tech

Record solar hydrogen production with concentrated sunlight

Hydrogen will play a key role in reducing our dependence on fossil fuels. It can be sustainably produced by using solar energy to split water molecules. The resulting clean energy can be stored, used to fuel cars or converted ...

Energy & Green Tech

Caffeine gives solar cells an energy boost

Scientists from the University of California, Los Angeles (UCLA) and Solargiga Energy in China have discovered that caffeine can help make a promising alternative to traditional solar cells more efficient at converting light ...

Engineering

New device paves the way to 3-D-printed organs, food

More than 113,000 people are currently on the national transplant list. And with a shortage of donors, this means that about 20 people will die every day while waiting for an organ, according to the U.S. Department of Health.

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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