Energy & Green Tech

Explaining the plummeting cost of solar power

The dramatic drop in the cost of solar photovoltaic (PV) modules, which has fallen by 99 percent over the last four decades, is often touted as a major success story for renewable energy technology. But one question has never ...

Energy & Green Tech

Biofuel from a container

More than four billion tons of crude oil are produced every year, and electricity from wind, solar and hydropower plants cannot entirely supplant fossil sources of energy. At best, renewables could cover the energy needed ...

Engineering

Origami, 3-D printing merge to make complex structures in one shot

By merging the ancient art of origami with 21st century technology, researchers have created a one-step approach to fabricating complex origami structures whose light weight, expandability, and strength could have applications ...

Computer Sciences

A new strategy to correct imperfections in occupancy grid maps

Researchers at Laboratório de Computação de Alto Desempenho (LCAD) of Universidade Federal do Espírito Santo (UFES), in Brazil, have devised a novel strategy for correcting imperfections in occupancy grid maps by correcting ...

Energy & Green Tech

Light multiplication for stable improvement of solar cells

Now that solar cells based on silicon technology have nearly reached their efficiency limits, researchers from all over the world are looking for alternative technologies to further improve solar cell efficiency. Physicists ...

Engineering

Laser-powered-drones may beat endurance hurdles

Hmm. Drones that can be recharged by a laser. So how long could they fly before having to land? How about "never mind"? We can look forward to seeing this idea in action. New Scientist had a story on September 3 that the ...

Energy & Green Tech

Dual-layer solar cell sets record for efficiently generating power

Materials scientists from the UCLA Samueli School of Engineering have developed a highly efficient thin-film solar cell that generates more energy from sunlight than typical solar panels, thanks to its double-layer design.

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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