Hemocyanin turns what color when oxygenated?

Hemocyanin turns what color when oxygenated?

• A. Red
• B. Blue
• C. Green
• D. Yellow

Answer: (B)

Hemocyanin is a copper-containing respiratory pigment. When it grabs oxygen, the copper centers switch from a reduced state to an oxidized state and form a copper–oxygen complex. This change changes which wavelengths of light the molecule absorbs, causing it to reflect blue light instead of the color it had when deoxygenated. In the deoxygenated form, the pigment is largely colorless or pale, so the vivid blue appears specifically with oxygen binding. This is different from hemoglobin, which uses iron and appears red when oxygenated. Green or yellow are not the typical colors produced by this copper-based pigment under normal conditions, so blue is the characteristic color of oxygenated hemocyanin.

Hemocyanin is a copper-containing respiratory pigment. When it grabs oxygen, the copper centers switch from a reduced state to an oxidized state and form a copper–oxygen complex. This change changes which wavelengths of light the molecule absorbs, causing it to reflect blue light instead of the color it had when deoxygenated. In the deoxygenated form, the pigment is largely colorless or pale, so the vivid blue appears specifically with oxygen binding. This is different from hemoglobin, which uses iron and appears red when oxygenated. Green or yellow are not the typical colors produced by this copper-based pigment under normal conditions, so blue is the characteristic color of oxygenated hemocyanin.