Hb, or hemoglobin, is red. This is due to the presence of the heme group within the hemoglobin molecule. The heme group's structure allows it to bind to oxygen, and this interaction contributes to the red color of blood.
Understanding Hemoglobin's Color
The references clearly state that hemoglobin is red. This is a fundamental characteristic stemming from the heme group's chemical composition and its interaction with oxygen. The shade of red can vary depending on oxygen saturation (bright red when oxygenated, darker red when deoxygenated), but the base color remains red.
- Reference 1: Explicitly states Hb is red because of the heme group.
- Reference 7: Confirms that blood (whose color is primarily determined by hemoglobin) is always red, varying only in shade.
- Reference 8: Describes hemoglobin as the main part of red blood cells.
The other references discuss various uses of the letters "HB," unrelated to the chemical composition of hemoglobin. These instances, referencing paint colors, school dress codes, or pencil grades, are not relevant to the color of the molecule Hb.
