|MadSci Network: Biochemistry|
Fearful Blood... Rhea - I wish you had told me what the blood actually did, that made you label it "afraid." After all, while blood is rather a complex substance, it is not complex enough to have emotions. Instead it was participating in a chemical reaction. Sour substances such as lemon juice and vinegar are acids. What you saw was a chemical reaction of an acid and a base (blood is somewhat basic). If you mix lemon juice and vinegar... no reaction, since they are both acids (sour substances). If you mix them with water, again, no reaction. Since water is neutral with a pH of 7, it is neither an acid or a base (actually it can also be both... but that is another story). If you are seeing a reaction between blood and these substances it must be a base. If blood were an acid or neutral, there would be no reaction. However, since something did happen, it must be a base. You may be wondering how I can be sure that it is an acid/base reaction at work, since I just told you blood is a complex substance. I am basing my assumption on the fact that both lemon juice and vinegar are fairly simple substances. Vinegar is mainly acetic acid, and lemon juice is mainly citric acid. To address the issue of blood types quickly - all blood reacted to the acids in the same way, regradless of type. What determines blood type has nothing to do with the the pH of the blood. Instead, it is a small string of molecules on the surface of the blood cells. A type cells have one string, B type cells have another, and AB type have both stings. O type cells have no string, which is why they are the "universal" donor. The + or - is another molecule string that is independant of the A B or O type. Hope this helps! Greta Hardin
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