A red blood cell contains over 250 million hemoglobin complexes. Hemoglobin is an iron-containing metalloprotein composed of four protein chains containing a ring-like heme group. Hemoglobin transports oxygen from the lungs to the rest of the body by reversibly binding oxygen to the iron in each heme.
raindow colors util.mroll 1, 180, 1 X-RAY DIFFRACTION 1.50 Å BakR d0mains rbc.glitch limited 500 eds. only ever minted