Which of the following is NOT a function of carbohydrates?

Carbohydrates serve several essential functions in biological systems, but they do not play a direct role in the transportation of solutes across cell membranes. Instead, their primary roles include serving as a source of energy, providing structure to cells, and contributing to the composition of various biological materials.

Carbohydrates function as energy stores and are utilized for energy metabolism in cells through processes like glycolysis and cellular respiration. Additionally, they play an integral role in the composition of cell walls, particularly in plants where cellulose, a carbohydrate, provides structural integrity.

The transportation of solutes across cell membranes is primarily facilitated by proteins, such as channels and transporters, rather than carbohydrates. Therefore, choosing the aspect of carbohydrates that does not align with their established functions highlights their specific roles in biological processes.