Many materials are made of the same kinds of molecules linked together many times and then stacked together like bricks in a wall to form large complexes. Similar to building a puzzle, visitors fit small molecules together to make larger molecules. Simple molecules built into long chains make new molecules that can be used to build structures in an organism. For example, the cellulose molecules in wood are made up of many glucose molecules linked together in a chain. These chains are later stacked together to make a strong structure that supports the wood - similar to linking paperclips together in a long chain. Although only examples of stacked chains are provided, chains can also be twisted into structures.
Molecules that Form Structure: Computer Interactive
Visitors investigate the molecular structures of four different organisms at this computer exhibit. Stepping through a set of images, visitors first identify familiar living things until they reach a chain of molecules that form a structure in each living thing. This exhibit, as well as the others like it in Marvelous Molecules, gives the sense of scale between living things and the molecules they are made up of.
At this exhibit, wool, silk, a crab shell, wood and a bone sample demonstrate molecule chains that provide strength and protection to living things. These molecular structures are not broken down easily even after the animal or plant is dead. The way molecules are linked together aids in determining the properties of that structure. Some molecules might be bonded to each other in lots of directions to form a rigid, hard structure such as wood or a crab shell. Other molecules might be able to slide past each other to make a flexible structure such as wool or silk.
It takes millions and millions of them to make up just part of a living thing. A single blade of grass contains 20 quadrillion chlorophyll molecules, a necessary component for its bright green color. Compare the molecules that make up a drop of water, olive oil and a bean.