 Welcome to the second lecture in the biophysics class. I'm going to start today too with a historical background showing you some very old movies. And then we're going to jump into a number of physical concepts that I've divided concept by concept, which hopefully will make it easier both for when you're studying and when you're looking at that later based on the study questions. Let's start it with movies. This is an old, very old movie generated by Cyrus Leventhal that was actually displayed on a computer screen, then filmed with 16mm camera and then many, many decades later this was 66. Mike Levitt and a few other friends transferred this back to computer and I got these from my friend Mike. This was the first ever computer representations of protein molecules. To you it's obvious that we can look at structures this way. You've probably seen this a ton of times but in the 1960s it was a miracle that instead of looking in columns of x, y and z coordinates for every single atom, you could visualize and try to understand conceptually what a molecule would look like. Myoglobin here was one of the first protein structures ever determined. This is from the LMB in Cambridge and it's a protein that binds oxygen in your muscle tissue and the part that binds oxygen is an iron containing heme group. We'll get back to that later in the class. I'm going to show you a second example also by Cyrus. This is the protein lysosyme. It's an enzyme that breaks down bacterial walls and it's present in tears, saliva, mucus, etc. And here too you can see properties of the structure. Later on in the class I'm going to tell you what these helices and beta sheets are but here too seeing this being able to rotate it live and everything was a breakthrough that you couldn't imagine when you were used to just either standing in the lab or considering protein structures a set of Cartesian coordinates. The person generating this I just figured that it's fun to see when most of these famous people when you look at them you see very senior photos where they're very serious and everything but the thing when Cyrus did this he was fairly young. He was also a Mac user. Well not that type of Mac. Here is the type of Mac Cyrus was using. It's a computer screen and mouse but note that you don't really have a keyboard. Actually you do have a keyboard. It's the typewriter but the typewriter is not directly connected to the screen. So you would type, get punch cards or something, let the computer run your program and then you would have this circular screen that you would look at and film it. There is no way you could have text direct text output. You might even see a mouse there in the background and this is what the mouse looked like. Of course they didn't call it mouse. It was just some sort of way to go. Mac stood for multi-axis computer. I'm not really sure what the multi aspect was. And then for fun I'll throw in a picture of Cyrus sitting and typing at one of these teleprompters. You're going to hear more about Cyrus and something called Leventhal's paradox later on in the class but I'll cover that when we get there. The next part is that we're going to be looking at specific elements of protein structure.