Benchmark 5C
The Living Environment: Cells
Grades 6-8, page 112

Within cells, many of the basic functions of organisms--such as extracting energy from food and getting rid of waste--are carried out. The way in which cells function is similar in all living organisms.

NSES Content Standard C 
Life Science: Structure and function in living systems
Grades 5-8, page 156
Cells carry on the many functions needed to sustain life. They grow and divide, thereby producing more cells. This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs.