• Question: Are white blood cells actually white? Why are they white?

    Asked by Alexiadepablo to Max, Francis, Ben on 16 Mar 2018.
    • Photo: Max Jamilly

      Max Jamilly answered on 16 Mar 2018:

      Great question. If you take some blood and spin it really really quickly in a tube, then the heaviest bits go to the bottom of the tube. From the top down, it goes yellowish, white, then red. The yellowish stuff is plasma – the watery component of your blood. The white layer is all the white blood cells and the red layer is red blood cells. So they really are named after their colours when you spin them down. Most cells are white because they don’t have anything to make them coloured. Red blood cells are red because they have a special pigment that helps them carry oxygen. White blood cells don’t have this pigment so, like most cells, they are just white!

    • Photo: Francis Man

      Francis Man answered on 16 Mar 2018:

      They’re more colourless than actually white. But when you have a lot of them on a small volume, they appear white.
      Red blood cells are red because they contain a lot of hemoglobin, which is a coloured molecule. White blood cells don’t have hemoglobin.

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