French Compound Aquarium Microscope (circa late 1800s)


Galleria
License Info
Image Use
Custom Photos
Partners
Site Info
Contact Us
Publications
Home

The Galleries:

Photo Gallery
Silicon Zoo
Pharmaceuticals
Chip Shots
Phytochemicals
DNA Gallery
Microscapes
Vitamins
Amino Acids
Birthstones
Religion Collection
Pesticides
BeerShots
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery
 

Urea Video No. 3
T1/DSL/Cable Stream

Also called carbamide, urea is a colorless, crystalline compound. It is the chief nitrogenous end product resulting from the metabolic breakdown of proteins in all mammals and some fishes. Commercially, urea is used as a fertilizer and feed supplement and is a base material for the manufacture of plastics and drugs. Urea functions as a stabilizer in nitrocellulose explosives and is a constituent of synthetically prepared resins.

Urea occurs not only in the urine of all mammals but also in their blood, bile, milk, and perspiration. During protein metabolism, amino groups (NH2) are removed from the amino acids and converted to ammonia (NH3). Ammonia is toxic to the body and is converted to urea by the liver. The urea then passes to the kidneys and is eventually excreted in the urine. The compound was first isolated from urine in 1773 and synthesized in 1828.

Excess nitrogen in the body is excreted in one of three forms: ammonia (as the ammonium ion), urea, and uric acid. Animals, such as fish, that live in the water excrete nitrogen as ammonia, which is quickly diluted by the aqueous environment. In terrestrial animals, the primary waste product of nitrogen metabolism is urea, a water-soluble compound. Birds excrete excess nitrogen in the form of uric acid, an insoluble chemical that allows birds to remove nitrogen without the use of water.

BACK TO UREA INDEX

Questions or comments? Send us an email.
© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Friday, Nov 13, 2015 at 02:19 PM
Access Count Since April 23, 2001: 11650
Microscopes provided by:
Visit the Nikon website. Visit the Olympus Microscopy Resource Center website.