| ACROSS | DOWN |
| 1 Used to take RBCs out of circulation before they rupture and start the recycling | 2 How RBCs get energy. |
| 7 Transports iron extracted from heme to bone marrow for reuse | 3 When RBCs appear in embryonic development |
| 8 Heme stripped of its iron; turns bruises green | 4 Peripheral buildup of bilirubin due to bile duct blockage, turning skin yellow |
| 9 Characterized by an inability to make two of the four hemoglobin subunits | 5 The formal name for the red blood cell |
| 12 Where red blood cells come from in folks older than embyros | 6 How much of the whole blood is RBCs; 42% of whole blood in adult women, 46% in adult men |
| 13 The pigment that actually carries oxygen and CO in RBCs | 10 Form in which old heme is excreted through bile |
| 16 Rupturing of an RBC | 11 Source of embryonic blood cells (and a heck of a lot of other types, too) |
| 18 Each subunit of hemoglobin has a molecule of this iron-containing pigment that binds oxygen | 14 What binds the carbon dioxide in hemoglobin |
| 19 Low hematocrit, low hemoglobin content or reduced oxygen carrying capacity | 15 The production of formed elements, to include RBCs |
| 20 Too many RBCs break down at once; urine turns red-brown with hemoglobin fragments | 17 Type of anemia; globular protein gene mutation results in crescent-shaped RBCs |
| 21 Along with ribosomes or mitochondria, an RBC lacks this |