Tuesday, December 28, 2010

The fire within

I warmed myself up tonight, shoveling snow off a patch of concrete. Orion, lying awkwardly on his back, shivered above as he aimed his bow at Taurus snorting high in the southeastern sky. On my way back in, I grabbed a handful of Brussels sprouts, plucked off the plant now surrounded by snow.

Winter is here, as good a reason as any to talk about our inner fire.


I love blasting my propane torch, flashing flame on steel faucets, a blush of condensation dulling the metal, water from fire. (Yep, a lit propane torch emits water--go ahead, check for yourself.)

Electrons trapped in high energy states tumble into the welcoming arms of oxygen, screaming with delight, releasing light and heat as they settle into their pajamas, ready for rest.

Yes, of course, I broke a few rules there. And, yes, of course, it's not quite accurate.

It's closer than you might realize.


Our cells need oxygen gas for one reason only--to accept electrons released from food as they travel down their energy gradients, settling into basal states of energy.

The oxygen accept the electrons (and associated protons) to form water. This happens in the innermost regions of our mitochondria, ancient critters subsumed by our forbears.

When you get down to it, we really don't need oxygen at all. Our mitochondrial slaves need it. If a cell doesn't have mitochondria, it has no need for oxygen.

Our red blood cells, designed to carry oxygen, use none of it themselves. They have no mitochondria, no need for oxygen. That's why you can keep RBC's packed in plastic bags waiting to be transfused.

Mitochondria are organelles, membrane wrapped particles in your cells that help convert food into a useful form of energy called ATP. Think of ATP as cash energy--no matter where you need a shot of energy in a cell, ATP can provide it.

(ATP works by adding instability to compounds--it's like when your crazy Aunt Margarita crashes onto the Thanksgiving table. Things are going to happen.....)

Mitochondria have their own DNA, most closely related to bacteria than to you. They reproduce on their own. They are an ancient life form that have been coexisting with larger cells for a long, long time.

This is so freaky I don't think it registers with most of my students. Mitochondria allow us to "burn" food down to carbon dioxide and water, releasing the energy caught by chloroplasts in plants.

What is fire? What happens to the fuel, to the oxygen?

Most adults here cannot answer this question, and it's pointless if your goal is to make money or get the girl or glom power.

Children love the question, and I doubt most ever get a decent answer. Heck, I know my students don't.

We teach chemistry as if it was handed down by Moses himself, the 10 Commandments in one hand, the Periodic Table of Elements in the other. I show them over and over and over again that water comes from a flame, and few can remember this two minutes after the demo is done.


Oxygen gas gets to your mitochondria by bouncing randomly around the inside of a cell. Since most of our cells burn a lot of food, their oxygen concentration is low relative to the fluid bathing them.

Just as fart molecules bumble their way across the room to embarrass their producer, oxygen molecules bounce around inside cells until they wander into a mitochondrion.

Red blood cells carry the oxygen molecules through our vessels, and they get dumped off where the oxygen concentration is lowest, needed only by the mitochondria, to produce the ATP needed to keep us alive.

This all happens very, very fast.

How fast? Cyanide blocks electrons from reaching oxygen inside the mitochondria. killing within minutes.

No oxygen, no fire, no life.

I have felt bodies quickly cool moments after death, no longer warmed by the trillions of mitochondrial furnaces within.

The shot of Orion is by John Gauvreau found at NASA's "Astronomy Picture of the Day."

Mitochondrion photo from Allen L. Bell, Ph.D, UNE COM here.

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