As the basic units of life, cells have needs and functions that are very similar to those of whole organisms. Students' understanding of the functions of cells develops along three major strands of benchmarks: the basic needs of organisms, the basic functions that are performed in organisms, and the structure of organisms and cells.
These strands of benchmarks first come together in middle school, where the benchmarks include the idea that the basic functions of organisms are carried out in cells. Later, when students know something about the structure of matter, they can understand the synthesis of protein molecules and the interactions of molecules within and between cells. This map has some important relationships to topics that will be mapped in the next edition of Atlas, including basic human functions and the commonalties evident within the diversity of life.
Almost all of the benchmarks in this map come together in the 6-8 benchmark "Within cells...," which lists the basic functions of cells. Similar functions are described in the Flow of Matter in Ecosystems map and the Flow of Energy in Ecosystems map on a macroscopic scale. In addition, the similarity of cell functions in all organisms is included in the Biological Evolution map, where it provides evidence for descent from common ancestors.
In 9-12, ideas about the functions common to all cells are further extended to the benchmark that different parts of the cell carry out specialized functions and eventually that the proteins made in the cell carry out its work.
Extremely important contributions to achieving benchmarks about cell function come from knowledge of the effect of the configuration of atoms in molecules, conditions that affect reaction rates, and catalysts. Two benchmarks from the Chemical Reactions map (in Chapter 4) appear here to support the 9-12 benchmarks.
Research in Benchmarks
Preliminary research indicates that it may be easier for students to understand that the cell is the basic unit of structure (which they can observe) than that the cell is the basic unit of function (which has to be inferred from experiments) (Dreyfus & Jungwirth, 1989). Research also shows that high-school students may hold various misconceptions about cells after traditional instruction (Dreyfus & Jungwirth, 1988).