When you think of proteins, you may think of things like meat and fish and beans...not little tiny molecules of protein. In biology, we've been learning about the little guys (protein molecules), and man, are they COOL. It's almost like science fiction. I have to marvel that man has been able to figure out and document all this stuff. I have to further marvel that something so interesting can be so well tucked away, hidden and obscured by bad writing and needless complexities. It takes me a good long while to unpack the interesting concepts from my incredibly dense textbook, which is clearly, CLEARLY not written by actual writers, but by scientists.
So, in simple language, what is so cool about proteins? Alot of things. For starters, there are 6 things a protein can do on the surface of a cell. So imagine a cell in you, or in your favorite cat, or whatever. You probably already know that cell has a plasma membrane around it. What you may not know is that proteins can embed themselves in that membrane and then serve some very useful functions. The shape of a protein determines its function. Some of the neat tasks it can perform:
The protein can act like a little tube, or channel, letting stuff in and out of the cell - a little passageway through the membrane. Actually, the protein can also "gate" the channel, only allowing certain things through or out of the cell. Even cooler, the protein can open one end, take something in, close itself, and then let it out the other side, so that the boundary between the inside and outside of the cell is always secure, but selected stuff is being securely transported from one side of the cell to the other.
Proteins can also attach to the cytoskeleton of the cell, sort of the framework of the cell, and provide some structure. They can perform like a little pump, taking in Nacl (3 molecules at a time) and pumping out potassium (2 molecules at a time) in a rotation, moving 5 molecules per transaction, and performing up to 60 transactions per second!
Proteins can also act like sentinels, alerting the cell to the presence of substances or signalling from the cell to other cells. Proteins can attach to other cells as well, in a neat little interlocking way like snapping lego together.
Proteins can also act as catalysts, or enzymes, and speed up some chemical processes. A protein can have a special site on it, called the active site, that something else (called a substrate) fits into. The protein tightens around it, stressed it's composition and changes it into something else. (For example, it might remove an electron, break a bond, or otherwise make an alteration to the substrate). There is a tiny on and off switch too, to let the protein known when to stop working. And, proteins can line up in a little chain called a biochemical pathway where the first guy makes what the second guy needs and the second guy makes what the third guy needs and so on until finally whatever the cell needs is manufactured. It's a tiny assembly line! And what's more, you have to have those to get energy and to use the other stuff in your body that you need to live.
It's truly amazing! They have diagrams of it all - but even cooler, they have actual photos of some proteins. Wow. I mean, WOW! Think about it - 75 years ago no one would have thought we could photograph a protein. Technology is so neat; there are benefits beyond Tivo, as good as Tivo is!
Proteins fold into shapes - the simplest being a helix, like a curly phone cord, or like a folded sheet, sort of like a furnace filter. Scientists are working on figuring out how proteins fold. To see some cool images of folding patterns and read an article on that, click here. They have four levels of complexity in folding, and can get pretty complicated looking.
It doesn't take long to conclude that life is not possible without proteins, and that these super amazing tiny machines are just brilliant little things that have oh so cleverly adapted themselves to do what needs to be done. The only thing more amazing to me is that both my textbook authors and my instructor have managed to take STUNNINGLY COOL STUFF like this and make it completely dull, boring, confusing and even downright inaccessible in some cases. In the end, I think the book authors are smart and were trying - and if I try really hard I can eventually understand what they are saying, but then I find myself wanting to rewrite the whole chapter because it could just be explained so much better!
Anyway, if you get bored, google proteins - look at the pictures, read a little bit, and I bet you too will gain a new respect for these itty bitty workers which reside in all of us.