Why is blood red?
Red blood cells contain a molecule that gives them their distinctive color. Have you ever wondered why scarlet blood pours out of your nose when you experience a nosebleed? Or why the veins in your skin look blue? It's all down to some colorful chemistry in your red blood cells. Red blood cells contain a molecule called hemoglobin, which binds and transports oxygen through our bodies. Hemoglobin is made up of four protein chains that each bind an additional ring-shaped chemical structure called heme . Our red blood cells are red because of the heme groups in hemoglobin. In turn, our blood is red because of the millions of red blood cells that it contains. Color plays an important role in many aspects of biology, explain the authors of a recent review article published in the journal Archives of Pathology & Laboratory Medicine . Here, Dr. Sergio Piña-Oviedo, of the Department of Hematopathology at the MD Anderson Cancer Center in Houston, TX, and co...