The average cell, be it plant or animal, can be thought of as a collection of machines. This may sound strange to some: to think that one’s inner workings on a microscopic level could be anything but organic, but are we not machine-like ourselves, on a macroscopic level? Do our arms not move by a series of pully-like tendons and muscles? Are those muscles not excited by electrical impulses produced by our nerves?
Just as the body of any animal, or plant for that matter, is somewhat analogous to a number of machines, so too are the functional parts of the cell.
Take ATP synthase for example. A protein found embedded in the inner membrane of the mitochondria (the structure responsible for energy production), ATP synthase takes adenosine diphosphate (ADP) and attaches a phosphate group to it, producing adenosine triphosphate (ATP), an energy-providing molecule used by the cell.
If there is any protein that seems very similar to a machine, it is ATP synthase, as it’s structure is remarkably similar to a turbine. Using the energy of a concentration gradient (going from high concentration to low concentration—think of a dam) across the inner membrane of the mitochondria, the “turbine” portion of ATP Synthase spins. In so doing, a conformational change in the shape of the protein occurs, causing ADP and a phosphate group to come together, producing ATP. Now, this process has certainly been simplified for the use of this article, but go ahead and search up a video of ATP synthase in action: you’ll be surprised at just how much it looks like a turbine.
Another remarkable, machine-like structure of the cell is the cytoskeleton. The cytoskeleton can be thought of in a number of ways: For one, it is the collection of struts and beams that maintain the shape of the cell; two, it is used to separate the cell during cell division; three, it is essential in the movement of the cell, through disassembly and reassembly on the fly, pushing the cell forward; but on top of all that, it is also used to transport “packages” or what are referred to as vesicles, of whatever the cell requires, wherever it requires them to be.
But how does a beam-like structure transport these vesicles? Not on it’s own, of course. With the help of what are called motor proteins, the vesicle in question is pulled along the cytoskeleton through the conversion of chemical energy into mechanical energy, much like a train pulls cargo across a country.
Now, lets take a look at larger-scale structures of the cell; the organelles.
The nucleus is like the server room, providing all the “coding” (in the form of genetic information) required to produce the necessary proteins that support the normal functioning of the cell. The ribosome acts like a translator, feeding the strands of genetic code into itself and reading the coding as it does so, producing the initial, primary structure of a protein, in the form of a chain of amino acids. This process occurs in the endoplasmic reticulum, as does the formation of lipids, or fats. As for the golgi apparatus, it’s purpose is to function as a packaging location, preparing the proteins and lipids that arrive from the endoplasmic reticulum for safe travel outside of the cell.
So, the inner workings of the average cell are certainly anything but average. After millions upon millions of years of evolution, the cell adapted, it changed, into something that contains structures not unlike the machinations of the modern age. At one point, the primordial cell may have been nothing more than a few membranes separating parts here and there, but today, they have become incredibly complicated, microscopic marvels, containing a whole other world of functional structures. Welcome to the machine.