Blow on it lightly and ask the class to describe the effect of the moving air on the Koosh ball's strands. Stick a small bit of clay on one of the strands. Ask students to describe how changes in the form of one of the strands affects the arrangement of the others. Explain that the Koosh ball's movements resemble those of a protein molecule, though the two don't look like each other. In the case of proteins, external factors like water molecules, not air, can affect surface projections of the protein and change its overall shape.
Proteins run our show.
Muscles, organs, hair, bone, and skin either contain or are made of proteins. They are a major component in all of our cells. Enzymes that run the chemical reactions in our bodies are proteins. A protein is a molecule that consists of a chain of amino acids. There are 20 different amino acids to choose from, and the genetic information in our DNA determines how they're put together.