Question

7 a cell membrane has a double layer of molecules. these molecules are made up of a phosphorus - containing \head\ and two long, fatty acid \tails.\ which of the following best explains why the molecules are classified as lipids? a they contain phosphorus. b they form a double layer. c they are made up of fatty acids. d they are found in the cell membrane.

Explanation:

Lipids are a class of biomolecules that include fats, oils, and phospholipids. Phospholipids, which are part of cell - membranes, are made up of fatty acid tails and a phosphate - containing head. The presence of fatty acids is a key characteristic of lipids. Just having phosphorus (A) is not the defining feature of lipids. Forming a double - layer (B) is a property of how they arrange in the cell membrane, not what classifies them as lipids. Being found in the cell membrane (D) is a location fact, not a defining characteristic for lipid classification.

Answer:

C. They are made up of fatty acids.