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hemoglobin
8 dictionary results for: Hemoglobin
Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This
he·mo·glo·bin 
[hee-muh-gloh-bin, hem-uh-] Pronunciation Key
[hee-muh-gloh-bin, hem-uh-] Pronunciation Key –noun Biochemistry.
| the oxygen-carrying pigment of red blood cells that gives them their red color and serves to convey oxygen to the tissues: occurs in reduced form (deoxyhemoglobin) in venous blood and in combination with oxygen (oxyhemoglobin) in arterial blood. Symbol: Hb |
Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.
American Heritage Dictionary - Cite This Source - Share This
| he·mo·glo·bin
(hē'mə-glō'bĭn) Pronunciation Key
n. Abbr. Hb or hg or hgb. The iron-containing respiratory pigment in red blood cells of vertebrates, consisting of about 6 percent heme and 94 percent globin. [Ultimately short for hematinoglobulin : hematin + globulin.] |
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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Online Etymology Dictionary - Cite This Source - Share This
hemoglobin
hemoglobin
1869, shortening of hæmatoglobin (1845), from Gk. haimato-, comb. form of haima (gen. haimatos) "blood" (see -emia) + globulin, a protein, from L. globulus "globule."
Online Etymology Dictionary, © 2001 Douglas Harper
WordNet - Cite This Source - Share This
| hemoglobin | |
noun | |
| a hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues; "fish have simpler hemoglobin than mammals" |
WordNet® 3.0, © 2006 by Princeton University.
The American Heritage Science Dictionary - Cite This Source - Share This
| hemoglobin
(hē'mə-glō'bĭn) Pronunciation Key
An iron-containing protein present in the blood of many animals that, in vertebrates, carries oxygen from the lungs to the tissues of the body and carries carbon dioxide from the tissues to the lungs. Hemoglobin is contained in the red blood cells of vertebrates and gives these cells their characteristic color. Hemoglobin is also found in many invertebrates, where it circulates freely in the blood. It consists of four peptide units, each attached to a nonprotein compound called heme that binds to oxygen. See Note at red blood cell.
Our Living Language : Ninety percent of the protein in red blood cells is made up of hemoglobin, the main oxygen transport molecule in mammals. A protein with four iron-containing subunits called hemes, hemoglobin is a complex molecule with a complex function. It must bind to oxygen in the lungs, then release that oxygen in the tissues, then bind to carbon dioxide in the tissues and release it in the lungs. Hemoglobin accomplishes oxygen transport by changing its structure, and even its substructures, around the oxygen-binding heme groups, making them more or less accessible to the environment. When oxygen binds to at least one of the heme groups (as happens in the oxygen-rich lungs), all of the heme groups become exposed to the environment and bind oxygen easily. The bond between oxygen and heme is a loose one, however, so that the oxygen can break free in the tissues, where the concentration of oxygen is relatively low, and thereby become available for use in the cells. When the last of the four heme subunits loses its oxygen, the structure of hemoglobin changes again, so that the size of the opening from the environment to the heme groups decreases, making it difficult for an oxygen molecule to rebind to the hemoglobin. In this way, hemoglobin stops itself from competing with the tissues for needed oxygen. When the red blood cell carrying hemoglobin returns to the lungs, where oxygen concentration is high, the cycle of oxygen binding, transport, and release starts again. Normally, iron binds with oxygen to form rust (iron oxide), but the structure of hemoglobin prevents this from happening, since it would inactivate the heme subunits. Carbon dioxide does not bind the heme in hemoglobin, but rather the amino groups at the ends of the hemoglobin's protein subunits. Hemoglobin transport is only one of a number of bodily mechanisms by which carbon dioxide travels from the tissues to the lungs for release to the air. |
The American Heritage® Science Dictionary
Copyright © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Copyright © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
American Heritage New Dictionary of Cultural Literacy, Third Edition - Cite This Source - Share This
hemoglobin [(hee-muh-gloh-bin)]
hemoglobin [(hee-muh-gloh-bin)]
A complex organic molecule containing iron that carries oxygen in the blood.
Note: Hemoglobin gives blood its characteristic red color.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
American Heritage Stedman's Medical Dictionary - Cite This Source - Share This
hemoglobin he·mo·glo·bin (hē'mə-glō'bĭn)
n.
Abbr. Hb
The red respiratory protein of red blood cells that transports oxygen as oxyhemoglobin from the lungs to the tissues, where the oxygen is readily released and the oxyhemoglobin becomes hemoglobin.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Webster's Revised Unabridged Dictionary - Cite This Source - Share This
Hemoglobin
Hem"o*glo"bin\, n. [Hemo- + globe.] (Physiol.) The normal coloring matter of the red blood corpuscles of vertebrate animals. It is composed of hematin and globulin, and is also called h[ae]matoglobulin. In arterial blood, it is always combined with oxygen, and is then called oxyhemoglobin. It crystallizes under different forms from different animals, and when crystallized, is called h[ae]matocrystallin. See Blood crystal, under Blood.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
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