by Steve Risner
Last week I introduced the cell—the basic building block of all life we know of. The complexity we find within these little bags of goo is just breathtaking. Processes too numerous to count and too tiny to fully understand fill these little factories that make us what we are. If you missed that particular introductory blog, you can find it here. Today I would like to just give a short explanation on what some of the organelles do (or what we believe they do). We'll start on the outside and move in.
The cell membrane is far more complicated than a barrier between the inside and outside of the cell. It is filled with receptors, doors, pores, and tons of little bits of machinery. Channels, gates, and pumps are infused in this thin layer made of mostly protein and fat. The actual structure of the cell membrane in and of itself is remarkable, but I'll not bog you down with the details. Protecting the internal environment of the cell and allowing things in and out are its most basic functions.
Just inside the cell membrane we find the cytosol, which is the goop of the cell and makes up about half the cell's volume on average. It is a salty, nutrient-rich slime that suspends much of the organelles in the cell.
Further in and closer to the nucleus, we find endoplasmic reticulum, also known as ER. This is a large series of interconnected sacs that primarily produce materials for use in the cell. Smooth ER makes lipids and breaks down toxic materials, while the rough ER makes proteins. Rough ER appears to be speckled and rough looking because it is infested with ribosomes, which are protein making machines. Ribosomes basically read RNA strands that give instructions for making specific proteins. These materials are often sent to the Golgi complex.
The Golgi complex puts the final touches on the materials sent to it and prepares them for shipping either somewhere inside the cell or to the cell membrane where it will be expelled through a specific channel or gate into the body.
How do all of these little machines work? How are they powered? Mitochondria. Mitochondria look like little beans inside the cell. Inside these powerhouses are numerous folds that increase surface area. Inside here, we find energy molecules being broken down and their energy used to power the cell. A cell will most likely burn over a billion ATP (energy molecules) every minute or two. We'll save the Kreb's cycle for another blog—it's amazing, too.
Deep within the cell, we find the nucleus—the big dot in the center of the cell. The nucleus has its own membrane, and within it we find the genetic material that holds the blueprint for you. We also find that the DNA is hard at work unzipping itself, copying small sections, and shipping them out to ribosomes so they can build a specific protein. Then we'll see it zip back up. Recall from my blog on DNA that this little strand is about 3 feet in length (that's a meter for the rest of the world) but invisible to the naked eye.
There are many, many other organelles, depending on the cell. We have vacuoles, which are basically just bubbles that carry substances inside the cell. There are centrioles, which have an interesting story. I was taught in high school and in college that the purpose of the centrioles, among other things, was to aid in cellular division. The explanation is more complex than that, but the funny part of this story is when the centrioles are removed, cellular division is unhindered. My biology professor told me this right after he told me what the function of centrioles was. “This is what they do, but if they're not there, the job still gets done.” Makes you wonder, doesn't it? There are also things like cilia for moving material outside the cell, and flagellum (basically a tail) for locomotion. The flagellum's parts list consists of over 40 different proteins and it looks and operates just like an outboard motor. Lysosomes basically eat stuff up. They envelop something and release agents that break it down. They also serve a more morbid function. If the cell needs to destroy itself, it signals the lysosomes to rupture inside the cell, spilling their enzymes out in the cell, causing it to basically eat itself. They have the nickname of “suicide bags.” Finally, the cytoskeleton is the internal skeleton of the cell and is found all over within the cytoplasm. However, unlike our skeletons, this structure is dynamic and is constantly changing—being broken down and reassembled all the time.
This is the short list. There are many, many more structures to cover, but for the sake of brevity and the sake of you losing interest (if I haven't already) we'll stop the list here. But what about outside the cell?
Cells are bound to each other. It would be very unfortunate if all our cells were just piled up in a heap and expected to maintain the proper shape. This process of bonding is called cellular adhesion, and there are several molecules used in the process. Perhaps you've seen Louie Giglio's presentation that talks about lamanin. If not, I highly recommend both of these videos that are sure to leave you speechless: Indescribable and How Great Is Our God.
The bottom line here is the cell is astoundingly complex and highly organized. What goes on in every cell of your body all the time is literally beyond comprehension. It's miraculous. I would encourage you to watch this wonderful video that attempts to demonstrate a few of the things happening in your cells. The video is fairly short, and you can view the narrated or non-narrated version. Prepare to have your mind blown.
God has made life, and He's made it so complicated it's simply naïve to attribute its existence to mindless processes and dumb luck. Darwinian evolution is logically bankrupt and void of demonstrable support in the real world. It exists in the minds of its adherents and quite literally nowhere else.
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