I think that a lot of cell biology courses, especially at the high-school and undergraduate level, fail to engender the appropriate sense of wonder at just how awesome the cell is. And I think that the main culprit in this is their presentation of the cell as a series of static slides. While that might have once been necessary due to technological limitation, we have plenty of new toys that can showcase the dynamic nature of cellular life (foremost among them the fluorescent proteins). There just isn’t an excuse anymore.
The presentation of the static cell is not only staggeringly boring, but also fundamentally misleading. The constituents of the cell move quite a bit, and without that motion bad things happen. This is most clear in the case of nerve cells.A nerve cell has a centralized nucleus, like most other cells, but it also has projections known as axons (which conduct signals away from the cell body) and dendrites (which conduct signals to the cell body). In some cases the length of these axons is measured in feet. To put that in perspective that’s about the distance between Dallas, TX and New Orleans, LA if you are the size of a mitochondrion. And if you are a mitochondrion your services may well be needed at the end of that axon, however, you are also going to need a supply of proteins that are translated back in the cell body (this is what you get for outsourcing part of your genome, but that’s a story for another time).
So how do they accomplish this? The same way we do: they commute. They commute really dang fast. And thanks to the magic of fluorescent proteins and YouTube, you can take a look for yourself: The above is a time lapse video of mitochondria zipping about in an axon. The full time elapsed is 100s. What you are seeing is a number of mitochondria commuting back and forth towards either the axon terminal or the nucleus. You may notice that they follow a particular path. That’s either a microfilament or a microtubule, components of the cellular structural network known as the cytoskeleton. This motion is a continuous race along the highways of the cytoskeleton to keep you alive and functional. Defects in mitochondrial motion are being linked to neurological disorders. If this delacate transport network (that is functioning in every single neuron in your body) is interrupted, you are going to feel the consequences.
That’s exciting. That’s what is at stake, and that’s why it is vitally important to get a grasp of how these things work. And yet, many professors just can’t seem to figure this out and so will drone on with their static slides and let the interest of their students die a tragic death.