Some of you have seen drawings that, as you gaze at them, seem to change back and forth between two different views. One such is the outline of a cube in three dimensions, where the scene oscillates between two different surfaces being closest to you. Such illusions are due to the way our minds work. There are things in nature, though, that superficially seem like they should be the same substance but, instead, have very different characteristics.
The sugar glucose is a simple, small molecule that is broken down in
the body to supply energy. Molecules of glucose can be linked chemically to form
molecules thousands of times larger. The fascinating thing is that they can be linked
together in different ways, resulting in either starch or cellulose. Starch is easily
disassembled and is used by plants to store the energy-containing glucose until that
sugar is needed. On the other hand, almost all organisms find cellulose impossibly
difficult to break apart, and instead of using cellulose for storage, plants use its
strength to form their very skeletons.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.