General Biology

Physics 111 Advanced Laboratory. Professor Jan Liphardt This video accompanies the Brownian Motion in Cells Experiment, providing students with an introduction to the theory, apparatus, and procedures. Perrin's experimental confirmation of Einstein's equation was an important piece of evidence to help settle a debate about the nature of matter that had begun nearly 2000 years earlier in the time of Democritus and Anaxagoras. Since then, a thorough understanding of Brownian motion has become essential for diverse fields that range from polymer physics to biophysics, aerodynamics to statistical mechanics, and even stock option pricing. Part 1. You will replicate Perrin's work with modern equipment. Then track the motion of nanoparticles suspended in liquids of various viscosities with a CCD camera connected to a microscope and a computer. You will use Matlab program to estimate the positions of the particles and analyze the data to see if it conforms to Einstein's model. Part 2. Using the same setup, you will track myosin-based transport of vesicles in a living onion cell. You will compare this motion to the Brownian motion you observed in the first part of the lab. ...