Also, any cell alive today had its origin in a preexisting cell. Going back to our definition of living things in Chapter One, it becomes clear that living things are made of at least one living cell. Structure and Scale of Molecules in the Cell Life may seem chaotic most days, but there is an incredible degree of organization within all living things. The foundation of the functioning cells that define all life forms is the atom. Atoms bond together to form molecules.
Proteins are the most numerous of chain molecules.
They are made up of amino acids strung end to end. DNA controls the shape of a sycamore leaf and the length of an alligator's tail. DNA is the genetic material that is the blueprint for all life. Some of the activities in this chapter require microscopes. If you don't have immediate access to these instruments, you may be able to arrange to use the science lab at a local school, environmental learning center, or museum.