Experiment - Curling DNA

Curling DNA

Purpose:
You will see how a long strand of DNA fit into the nucleus of a cell.

Supplies:
yarn or string
a large button with holes through it, or a metal washer

Cut a length of yarn or string 3’-4’ long.

String each end through a hole in the button, and tie the ends together, or tie the ends together and tie the middle of the loop to the metal washer.

Hold one end of the loop in each hand, with the button/washer in between your hands. Swing the button/washer in a circle, winding the loop of string as tightly as you can.

Stop swinging and release the tension. Watch the string immediately coil or kink up into a tight mass.

Results, Questions:
1. How did the wadded handful of string before twisting compare in size with the string after twisting? (It seemed much larger)

2. Is it actually the same amount of string? (Yes)

Applications:
1. Imagine a string of DNA about 6’ long and 80 billionths of an inch wide. This is how it fits into the nucleus of a cell.