Alberta Written Barber Practice Exam

What color is blood when it carries oxygen?

1. Dark red

2. Bright red

3. Blue

4. Pale yellow

The correct answer is: Bright red

Blood appears bright red when it is carrying oxygen. This is due to the binding of oxygen to hemoglobin, a protein in red blood cells. When oxygen attaches to hemoglobin, it alters the structure of the molecule so that it reflects light in such a way that our eyes perceive it as bright red. This bright red color is most visible in the arteries, which transport oxygenated blood away from the heart to the rest of the body. In contrast, deoxygenated blood, which is returning to the heart after delivering oxygen, is darker in appearance, often described as dark red. The other options, such as blue and pale yellow, do not accurately represent the color of oxygenated blood. Blood does not appear blue in humans under normal circumstances; this misconception arises from the way light penetrates the skin, making veins appear bluish. Pale yellow refers to plasma, the liquid component of blood, but does not pertain to the color of blood that is carrying oxygen.