Biophysics

Random Integer Line Graph

This line graph was created by randomly choosing 8 integers from -1 to 7 and plotting them on the graph. Each time the code is run, the line graph looks different, as the values are chosen randomly each time.

Random Walks Graph

This graph shows 5 different random walks, each shown by a different color. Each line starts at the same point but ends up in a different place. For example, the green line ended up far away from the other lines. The graph was also created by pure randomness.

Random Walks Histogram

This histogram shows the locations of 10,000 different random walks at 5 different x-coordinates: 200, 400, 600, 800, and 1,000.

The Gambler's Ruin

This graph shows the Gambler's Ruin, a problem involving random walks in which both gamblers begin with a certain amount of money, and play back and forth until one gambler ends with all the money and the other gambler ends with nothing. In this run of the program, both gamblers began with $150. Gambler 1 ended with $0 and Gambler 2 with $300.


What is Biophysics?

Biophysics is the study of the interaction between molecules, which allows for the sustainability of life. The key idea of biophysics is that molecules move randomly, and this random movement is critical to understanding the interaction between biological molecules. Biology relies on four main macromolecules – carbohydrates, lipids, proteins, and nucleic acids. The ways in which these four macromolecules interact, specifically, allows for life and unique phenomena in biology.

Let's take a look at one specific part of the cell, for example: the cell membrane. This membrane, also referred to as a phospholipid bilayer, is crucial to the efficiency of the cell. Structurally, the amphipathic phospholipids line up facing away from other to create a hydrophobic space in between. Water is only able to interact with the hydrophilic heads of the phospholipids, not the tails, so it cannot pass through the membrane on its own. Thus, it needs the help of aquaporins (a special type of protein) to pass through the membrane. Other proteins line the membrane with various functions – enzymatic activity, cell-cell recognition, channels for molecules, etc. Carbohydrates can sit on some proteins as "flags" for the cell, allowing it to be identified when other cells come into contact with it. These carbohydrate-proteins are known as glycoproteins. Finally, another type of lipid – cholesterol – lines the membrane and acts as a regulator for its fluidity.

Now how does this all relate to biophysics? In this one structure of a cell, there are at least six molecules interacting with each other: two lipids (phospholipids and cholesterol), proteins, carbohydrates, water, and other molecules trying to pass in/out of the membrane. The random movement of molecules on both sides of the cell membrane allows for the rapid exchange of molecules into and out of the cell. Additionally, the physics behind the movement of these molecules (active and passive transport, simple and facilitated diffusion) accounts for the metabolic processes going on in the cell that allows for the sustainability of life.