The following question is in the public domain. It concerns a description of the unique characteristics of chemical substances and macromolecules used by living systems, as that subject relates to the correlation between stucture and function of biologically important molecules and their relationship to cell processes. It was directly lifted from the web site of public release questions posted by a state department of education on the date of posting (link).
Which statement describes the major role of lipids within a cell?
A. They cause DNA to replicate.
B. They move RNA in the cytoplasm.
C. They catalyze chemical reactions in the cell cytoplasm.
D. They are the main structural components of membranes.