Biochemistry at its finest!

Biochemistry at its finest! Yesterday, I attended my last 7.05 (Biochemistry) lecture taught by Prof. Michael Yaffe. Three professors co-teach the class and Yaffe taught for the first month of the semester. Indeed, it was a sad day. For 1.5 hours three times a week, hundreds of students fill 10-250 (one of the giant lecture halls) to watch Yaffe cover crazy amounts of information in very little time. By the end of every lecture, you probably have four pages of very colorful notes and 9 boards filled with pretty picture of molecules and processes. The picture below is what the board looked like last Friday: Using these boards, Prof. Yaffe explained the metabolic process that prevents you from bleeding to death after a measly paper cut! Basically, everyone knows that when a blood vessel is damaged, a bunch of platelets congregate to repair the cut by creating a clot. What you may not know is that this process is facilitated by the formation of a mesh made out of a protein called fibrin. This fibrin is formed by a long and relatively complicated process (called a coagulation cascade). The cascade begins with a vascular injury (a cut) that initiates an extrinsic pathway (aptly named because the source is outside of your body), which initiates an intrinsic pathway (named such since all of the necessary components already exist in your circulatory system). In the end, this complex process results in a reaction at the right place at the right time unless you have something like hemophilia. (Dont continue reading this if you plan on taking 7.05 and dont want the surprise to be ruined!) Thats all well and good, but the *craziness* began when Yaffe asked if anyone wanted to donate blood for a demonstration. I thought he was joking and nobody volunteered. So, he called up the head TA (teaching assistant) and the TA dutifully sat in a chair at the front of the classroom as Yaffe pulled out rubber gloves, a syringe, and some tubes. He drew a considerable amount of blood (2 vials full), while everyone watched in awe (except for the ones who had heard about it before, they seemed more amused from everyone elses reaction). Then, he added a clotting factor to one tube and continued with class. An hour later, he showed that one tube had a huge clot in it, while the other was the same as before. By the way, Yaffe is an MD/PhD who studies protein-protein interactions and signal transduction pathways by lipid and protein phosphorylation. His lab is in the Center for Cancer Research, where I did my first UROP (well, not in his lab in particular, just in the same building.) Im sure he would draw your blood, too, if you asked politely.