The Chemistry of the Color of Life

Let’s talk about the molecules of blood

Blood is a mixture of different substances (plasma, red blood cells, white blood cells, platelets — you know, all the things you learned in middle school science class), but its fame is mostly due to that instantly-recognizable red color. Once I began researching this topic, two facets of blood became of chemical interest to me: 1) (most obviously) “what is the chemistry of the red coloration?” and 2) “how does it transport oxygen?”

As always, I won’t go too in-depth for these questions — my goal is to not scare off anyone with jargon. Chemistry (especially organic chemistry) truly has a language of its own, and I try to avoid that like the plague. When I do dip into it, I break it down word-wise as well as in layman’s terms. Nonetheless, I want to get into these two questions because they segue nicely into some interesting factoids about chemistry and other stuff in general — you’ll see what I mean shortly.

(“Segue” looks like it should be pronounced “seh-goo-eee”… but I digress.)

Hemoglobin and Porphyrins

A lot of people say that hemoglobin is responsible for the color of blood, and that is a little misleading, yet partially correct. Hemoglobin is a protein within a red blood cell that contains a collection of atoms in specific arrangement called a “heme group.” The heme group (or just “the heme”) is primarily responsible for the color of blood. You can see how the…