Phospholipids ______ ______ into a bilayer.

Phospholipids ______ ______ into a bilayer.

• A. self assemble
• B. self-assemble
• C. pack tightly
• D. form micelles

Answer: (A)

Phospholipids are amphipathic, with hydrophilic heads and hydrophobic tails. In water they spontaneously organize to shield the tails from water, so the heads face the aqueous environment on both sides while the tails tuck inside. This self-assembly creates a bilayer, the essential structure of cell membranes, where the arrangement is energetically favorable and fluid rather than rigid. That spontaneous organization into a bilayer is described by the phrase self assemble, highlighting that the molecules arrange themselves without needing external forces. The bilayer form is preferred over packing tightly because the membrane remains fluid and allows lateral movement of lipids and proteins. It’s also not micelles, which are typically formed by lipids with a single tail that curve into spherical shapes; phospholipids with two tails favor the planar bilayer structure.

Phospholipids are amphipathic, with hydrophilic heads and hydrophobic tails. In water they spontaneously organize to shield the tails from water, so the heads face the aqueous environment on both sides while the tails tuck inside. This self-assembly creates a bilayer, the essential structure of cell membranes, where the arrangement is energetically favorable and fluid rather than rigid.

That spontaneous organization into a bilayer is described by the phrase self assemble, highlighting that the molecules arrange themselves without needing external forces. The bilayer form is preferred over packing tightly because the membrane remains fluid and allows lateral movement of lipids and proteins. It’s also not micelles, which are typically formed by lipids with a single tail that curve into spherical shapes; phospholipids with two tails favor the planar bilayer structure.