Which of the following is a key component of cell membranes?

Cholesterol is a crucial component of cell membranes, playing multiple roles in maintaining cell structure and function. It fits between the phospholipids in the membrane, helping to stabilize the fluidity of the membrane at varying temperatures. Cholesterol prevents the fatty acid chains of the phospholipids from packing too tightly together, which helps maintain the flexibility of the membrane. This fluidity is essential for the normal functioning of cells, as it allows for the proper functioning of membrane proteins and facilitates cellular processes such as signaling and transport.

While carbohydrates, nucleic acids, and glucose are all important biological molecules, they do not serve the same structural role within cell membranes. Carbohydrates are often found on the exterior surface of the cell membrane, attached to proteins or lipids, where they play a role in cell recognition and signaling. Nucleic acids, such as DNA and RNA, primarily function in genetic information storage and transfer, and are not structural components of the membrane. Glucose serves as a key energy source for cells but does not contribute directly to the structural integrity of cell membranes. Thus, cholesterol stands out as a vital component of cell membranes.