In the context of the lipid bilayer, what best describes a phospholipid?

• A. A carbohydrate made of repeating monosaccharides that forms the main structural component of membranes
• B. An amphipathic molecule with a hydrophilic phosphate-containing head and two hydrophobic fatty acid tails
• C. A steroid with four fused carbon rings that forms channels allowing ions to cross the membrane
• D. A polymer of amino acids linked by peptide bonds that primarily functions as an enzyme in membranes

Answer: (B)