Stretching DNA

When we think of DNA molecules, we usually imagine two strings that coil around each other. However, not many people know that a DNA molecule in its natural state is more tangled than that Rapunzel Disney movie. Bad jokes aside, this represents an obstacle for scientists that need to observe the molecules closely.

This is why they have worked out a way of stretching the DNA string and photograph it through a microscope. If you’re interested in learning more about this process, then Stretching DNA is an application that you could find helpful.

Stretching DNA is a Java based application that accurately simulates the stretching of a DNA molecule, or so I think. Since I’m not knowledgeable in biology or physics (or biophysics, for that matter), I’m not able to judge the accuracy of the experiment. In fact, the simulation’s graphics remind of a Joan Miró painting more than anything else.

Keep in mind that Stretching DNA was created for educational purposes, so you won’t get much insight out of it if a teacher doesn’t provide more than a few additional explanations, or if you don’t have any prior knowledge of the DNA stretching process.

Basically, there’s a DNA molecule that is held by a bead that is held by a pair of optical tweezers. This is a scientific instrument which uses a laser beam to keep the bead in place, along with one end of the DNA string; the other end is held by some sort of pin.

You can adjust the power and move it around, but you can also move the bead. You can choose to have arrows indicate what forces are at work, but you may also measure the string with a ruler. While you don’t get to take a look at the microscopic details of the molecule, Stretching DNA is still an interesting simulation that can help you learn more about a complex physical process.