Is Erythrocruorin red? (aka earthworm blood color)

In summary, there is a misconception that earthworm blood is red because it contains hemoglobin, the same oxygen-transporting protein found in our bodies. However, this is not entirely accurate as the oxygen-carrying group in earthworms is Erythrocruorin, which is not the same as hemoglobin. Additionally, the color of blood in humans is primarily due to the oxidation state of iron in hemoglobin. In other organisms that use copper to transport oxygen, their blood may appear blue due to the oxidation state of copper. Further research is needed to confirm the color of oxygenated Erythrocruorin in earthworms.
  • #1
Vree
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Some grade shool books claim that earthworm blood is red because it has hemoglobin, like ours.

Now right away you need to clarify what "hemoglobin" can mean. I'll start off by saying that IMO it is incorrect to use the word for every oxygen-transporting protein. Moreover it is false to assert that the oxygen-transporting molecule in earthworms is the same molecule that is found in our body. Therefore arguing the result with this method is false.

So what is the correct way to prove it?
Obviously, if you could say that the respiratory pigment in the worm (Erythrocruorin) is of a red color when oxygenated.

Funny thing is, I could never find any study that would confirm this, only the aforementioned "earthworms have red blood" ones.

Could somebody help to improve this popular misconception?

(& Also the Wikipedia article where this question already got asked by someone.)
 
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  • #2
What is the oxygen carrying group? The colour of blood in humans is primarily the result of the oxidation state of the iron in haemoglobin. I'm not certain, but I think, that myoglobin - the oxygen transporting protein in mammalian muscles - is red in colour when oxygenated. Again, I believe this is due to the colour created by the oxidation state of iron at the core of the oxygen transporting proteins.

Likewise, in some organisms that use copper to transport oxygen, there blood is blue due to the oxidation state of copper. Copper oxide is blue/green.

I'm not certain. Here's a cool post from someone more knowledgeable than me: http://www.quora.com/Why-is-copper-oxide-green
 
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1. Is Erythrocruorin the only type of blood in earthworms?

No, earthworms have a variety of different types of blood, including erythrocruorin, chlorocruorin, and hemerythrin. Erythrocruorin is the most abundant type of blood in earthworms and is responsible for their red color.

2. Why is Erythrocruorin red?

Erythrocruorin is red because it contains a high concentration of iron-containing molecules called heme. These heme molecules bind to oxygen and give the blood its characteristic red color.

3. Does Erythrocruorin serve the same function as hemoglobin in human blood?

Yes, Erythrocruorin serves a similar function to hemoglobin in human blood. It carries oxygen throughout the body and helps regulate the earthworm's metabolism.

4. Can the color of Erythrocruorin change?

Yes, the color of Erythrocruorin can change depending on the oxygen levels in the earthworm's environment. When oxygen levels are high, the blood appears bright red, but when oxygen levels are low, the blood can appear a darker red or even purple.

5. Is the color of Erythrocruorin important for earthworms?

Yes, the color of Erythrocruorin is important for earthworms because it allows them to transport oxygen efficiently throughout their bodies. This is crucial for their survival, as they require oxygen for respiration and metabolism.

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